DF - Dermatology Foundation

A DERMATOLOGY FOUNDATION PUBLICATION
®
SPONSORED BY MEDICIS, THE DERMATOLOGY COMPANY
VOL. 24 NO. 4
WINTER 2005/6
DERMATOLOGY
FOCUS
™
DF
Dendritic Cells With the Right
Stuff—The Third Generation
Anti-Melanoma Vaccine
The Challenge: $5 Million
in Annual Research Funds by 2008
2005 Honorary Award Profiles: Paul S.
Russell, MD; W. Harrison Turner III, MD
Fitzpatrick Legacy Fund Welcomes
First Six Members
Where Are They Now?—
Amy S. Paller, MD, Specialty Leader
A
fter 15 years of disappointingly modest
results produced by the first two
generations of therapeutic vaccines for
melanoma, a third generation is taking giant
steps toward success propelled by seminal
advances in our understanding of dendritic
cell biology. Key among the pioneers in
understanding this professional antigenpresenting cell and applying the results to
reconfiguring the anti-cancer vaccine is
Pawel Kalinski, MD, PhD, who has been with
the Department of Surgery and the Cancer
Institute at the University of Pittsburgh Cancer
Institute since 2000. His dendritic cell-based
vaccine is entering clinical trials for both
melanoma and cutaneous T-cell lymphoma,
with colorectal cancer, glioma, head and neck
cancer, and prostate cancer in the wings.
The concept of therapeutic vaccines
for cancer rests on powerful logic—outsmarting the cancer’s resilient immuno-
suppressive abilities by presenting effective cancer antigens to T cells in a way that
guarantees recognition, and then identification and killing of tumor cells. This
approach is particularly appealing for
challenging cancers like melanoma, which
is responsible for most (almost 75%) of the
10,600 skin cancer deaths each year. The
problem has been in finding an effective
way to accomplish this.
As modified versions of the earlier vaccines have typically failed to realize their
promise, the frustrating reality of a
far greater complexity has emerged. The
first published account of a therapeutic
vaccine in the U.S.—targeting metastatic
melanoma—which appeared in 1990, typifies the pattern. Led by Malcolm S.
Mitchell, MD (then at USC, now at Wayne
State University’s Karmanos Cancer
Institute), this first attempt at what became
Melacine combined an allogeneic tumor lysate with an
immunostimulant mix. Longrange results have remained
extremely modest despite
attempts to boost its impact
by increasing the pool of
allogeneic melanoma peptides and adding additional
immune stimulants and/or
chemoactive agents. Some
combinations have also
produced severe toxicity.
IL-18 induces lymph node-responsive NK cells.
Until recently, vaccine
IL-18-conditioned NK cells (yellow), highly responsive to lymph
node-associated chemokines, migrate to the T-cell zones (blue)
development’s artificial jumpof lymph nodes where they can help to polarize potent DC1s to
start of the immune system
generate Th1 immune responses. Arrows point to yellow cells
has focused on two issues:
shown in enlargements. (Reprinted with permission from J Exp
Med. 2005;202:p.944.)
Also In This Issue
(Continued on page 2)
Focus on Research
How Toll-Like Receptors
Orchestrate the Immune
Response—Learning
Through Leprosy
Robert L. Modlin, MD
Professor and Chief of Dermatology
David Geffen School of Medicine at UCLA
M
odlin’s interest
in the immune
system’s response to
infection found an
intriguing focus during his dermatology
residency 25 years
ago at the USC
Medical Center during his required rota- Robert L. Modlin, MD
tion through their Hansen’s Disease Clinic.
Because leprosy is a spectral disease—
with a clear relationship between the localized tuberculoid and disseminated lepromatous ends of the clinical spectrum and
immune success or failure, respectively—
“I thought it would be a great model for
understanding how our immune system
fights infection,” he recalls, “and the cutaneous lesions are easily accessible for
observation and study.”
Leprosy is characterized by the
development of granulomatous or neurotrophic lesions in affected tissues. This
disease is encountered in the United
States primarily among immigrant populations and within tiny pockets in Texas
and Louisiana, but it remains a serious
(Continued on page 11)
(1) the most effective antigens (those common to all tumors of a given type—and if so,
which ones—or autologous antigens from
the individual tumor’s repertoire), and (2)
the most effective way to deliver them to
the T cells and increase T cell numbers.
Kalinski, however, has homed in on
the earliest steps in initiating the desired
immune response. He has identified the
essential constellation of key elements for
effectively activating cell-mediated immunity, beginning with the right dendritic cell
phenotype. Without this, providing tumor
antigens and immune system boosters cannot adequately surmount cancer-generated immunosuppression. Kalinski finds this
crucial dendritic cell phenotype missing
from current vaccine attempts, and he has
determined, by a careful sequence of studies, how to coax it into being.
“Discovering” the Dendritic Cell
Kalinski’s passion for improving the
efficacy of anti-cancer vaccines dates to
the beginning of his medical studies over
20 years ago, and the dendritic cell soon
became his focus for doing this. From the
start, his primary concern was finding
a way to deal with the minimal posttreatment residue in cancer. “Eliminating
the majority of the tumor cells is something that we were already doing quite
well,” Kalinski says, “with radiotherapy,
chemotherapies, and some forms of
immunotherapy. But despite a magnificent
response to therapy in the majority of
patients, most of them relapse and eventually die. The problem is how to take care of
those few persistant remaining cells. To my
mind,” he adds, “using the immune system
has always made the most sense.” Kalinski
studied immunology and immunotherapy
at the University of Warsaw, where he did
his medical studies, and worked in a
transplantation laboratory. He eventually spent seven years at the University of
Amsterdam in the laboratory of Martien
L. Kapsenberg, PhD (Department of Cell
Biology and Histology, Academic Medical
Center), which explores the pathways
between antigen and immune responsiveness. Kalinski developed a background in
contact dermatitis and atopic dermatitis,
and has been able to apply many of his
observations there to revamping the anticancer vaccine paradigm.
Kalinski quickly found dendritic cells
intriguing to observe, challenging to understand, and above all, compelling in their
logic. As the primary antigen-presenting
cells, they are carriers of pathogen-related
information within the immune system.
They make direct contact with the
2
Kalinski had already shown that
pathogen in the peripheral tissue, then
priming naive Th cells with IL-12-deficient
migrate to the lymph node with the specifDC that have been stimulated by bacterial
ic antigen they have incorporated, where
lipopolysaccharides (LPS)—which northey mature and are able to prime naive T
mally provoke a cell-mediated immune
cells (see box on page 7), which then initiresponse—generates a mixed cytokine
ate an immune response. “Instead of focusresponse instead. These Th0 cells produce
ing our immunotherapeutic efforts on final
substantial levels of IL-4 and IL-5, and
effector cells of the immune response,”
also IFN-. Then he demonstrated that
Kalinski explains, “I thought we could
even partially inhibiting the DC’s IL-12influence immune responsiveness much
producing capability—by exposure to
more comprehensively by targeting the
the immunosuppressive factor PGE2 (the
cells that first initiate the train of events.”
inflammatory mediator prostaglandin E2)
This meant learning the precise steps by
before LPS stimulawhich dendritic cells
tion—skews priming
produce immunoreto Th2 cells. Adding
sponsive T cells, and
exogenous IL-12 overthen determining
ruled this Th2-driving
how to ensure that
behavior. Pretreating
a vaccine recapituDC with glucocorlates these steps
ticoids—immunowhen tumor antisuppressives whose
gens are made availimpact on DC wasn’t
able. Then the effecyet well defined—
tor end of the
induced Th2 cells
process would simPawel Kalinski, MD, PhD
producing high levels
ply do its job.
of IL-5 and the anti-inflammatory/immunoKalinski began to study interactions
suppressive cytokine IL-10. Again, the
between dendritic cells and lymphocytes
pattern reverted to Th1 when IL-12 was
and the differentiation of naive helper T
supplied from the outside. Pre-exposure
cells into the Th1 phenotype (which actiof DCs to the immunosuppressive cytokine
vates cellular immunity) and Th2 phenotye
IL-10 simply stopped these antigen(which suppresses Th1 activity and initipresenting cells in their tracks, and they
ates the humoral immune response), and
never matured.
progressed to the interactions of dendritic
Looking at the normal time course of
cells with cytotoxic effectors—natural killer
the DC’s IL-12-production while in the
(NK) cells and CD8+ T cells.
lymph node, Kalinski saw that the initial
The Dendritic Cell and IL-12
robust output during their first several
Kapsenberg’s lab had already estabhours of interacting with T cells diminishlished the fact that dendritic cells (DC) in
es as they mature because the DC loses its
humans—once they are stimulated by a
ability to respond to IFN-. He had also
pathogen—are responsible for the differenseen that mature DCs are impervious to
tiation of naive T cells into Th1 or Th2 cells
PGE2 and glucocorticoid influence. This
(see box on page 7). DC production of ILunderlined the need for influencing DC
12 was known to participate in inducing
behavior, and thus Th cell phenotype,
the Th1 phenotype. Normally, pathogenvery early in its history.
activated DCs transiently increase the
The Plastic Dendritic Cell—The
intensity of their antigen uptake and begin
Third Signal and Polarization
moving toward draining lymph nodes,
up-regulating their expression of co-stimuA critical early insight for Kalinski and
latory molecules that will allow them to
his co-workers was their realization “that
interact with naive Th cells there. As DCs
there are different dendritic cell phenoevolve from antigen-trapping to mature
types. Although they all arise from the
immunostimulatory cells in the lymph
same basic pool of immature cells, a DC
node, they begin producing IL-12 when (1)
will perform different functions depending
the DC’s CD40 receptor binds with its
on both its stage of activation and which
T-cell–carried ligand, and (2) the type 1
pathogens and cytokines or cells have acticytokine IFN- is also present. Then the
vated it (see table on page 3).” The phenostrong IL-12 presence becomes a potent
type that evolves under these influences
stimulant for IFN- production by the
determines what that dendritic cell can
Th cell, hallmark of the Th1 phenotype.
and cannot do. This fundamental discovThe mature T cell migrates from lymph
ery has been the springboard for Kalinski’s
node to tissue to encounter the pathogen.
subsequent research.
Dermatology Foundation
Until this realization, which he published in 1999, the conventional wisdom had
regarded all myeloid dendritic cells (the
most common type) as capable of inducing
Th1 responses, with other types of antigenpresenting cells responsible for induction of
Th2 responses. Integrating his research and
observations from other labs had made it
clear to him that Th1 cells—and thus a cellmediated immune response—can indeed
be launched by myeloid DCs, but only
by those that have differentiated to an
IL-12–producing phenotype. And DCs that
have differentiated to an IL-12–poor phenotype will push the naive T cell to a Th2 phenotype. Kalinski used the term polarization
to describe the differentiation/maturation
process from naive to distinctive phenotype. Once immature sentinel DCs in the
peripheral tissue acquire antigen and
migrate to the lymph node, they are polarized by IFN- to DC1, or by PGE2 to DC2.
Naive Th cells in the lymph node that interact with DC1 are polarized to Th1, and those
interacting with DC2 are polarized to Th2.
This phenomenon of polarization led
Kalinski to his concept of the third signal
received by naive Th cells in the lymph
node. The first signal—via the antigen—provides information about the pathogen and
triggers the T-cell receptor. The second signal—enabling activation—occurs through
co-stimulatory molecules. The third signal
induces polarization. The primary third
signal source for Th1 cells is the cytokine
IL-12. The factors that affect the ability of
DCs to deliver this third signal are those
that modulate IL-12 production, including
those that diminish it: PGE2, IL-10, corticosteroids, and interferons.
Kalinski explains that “the conditions
of DC maturation basically ‘tell’ the DC
what to do. Because DCs have a memory—
very much as T and B cells do—they are
able to ‘teach’ the naive T cells what to
do.” This polarization, as it determines the
nature of the immune response, became
the centerpiece of Kalinski’s revised
approach to anti-cancer vaccines.
IL-12—All or Nothing
Today’s gold standard for DC-based
cancer vaccines includes PGE2 in the
cytokine cocktail (added to TNF-, IL-1,
and IL-6) used to expand and produce
mature DCs for current anti-cancer vaccination protocols. One favorable study
reported that it synergizes with TNF- to
induce production of the IL-12p40 subunit in DCs. Because Kalinski was very
familiar with the opposite roles played by
the complete IL-12 cytokine and its p40
subunit, he looked carefully to determine
whether PGE2-driven stimulation of the
p40 subunit is accompanied by transcription of the gene for the p35 component,
and by secretion of bioactive IL-12p70.
His results—published four years ago—
indicated that PGE2’s up-regulation of IL12p40 is an end result. There is no progression to form the complete bioactive
protein. An even greater indictment was
confirmation that PGE2 actually suppresses production of IL-12p70 that would
otherwise be induced by the pathogenassociated LPS, or by binding with the
naive Th cell’s CD40L molecule. This
agrees with the Th2-promoting activity of
PGE2 that Kalinski and others had documented, and argues against any use of this
inflammatory mediator in therapeutic vaccines that rely on Th1 activity.
In the interests of improved anti-cancer therapy, Kalinski wanted to see if he
could stimulate production of the complete IL-12 cytokine and transform Th2 cells
into a Th1 population—and thus into effector cells protecting against intracellular
infections and cancer. He separated cultured human Th2 cells into several groups,
restimulating them under different conditions. Interacting with B cells simply preserved the polarized
Th2 phenotype, but
DC1s vs Immature DCs and
adding exogenous ILStandard (Nonpolarized) Mature DCs
12p70 to this mix shiftStandard
ed them to Th1 cells.
Immature
Mature
Polarized
Unexpectedly, restimExpression of
ulating with already
co-stimulatory molecules
low
high
high
mature DC1 cells also
IL-12–producing capacity
low/high*
low
high
reversed their phenoResistance to inhibition
low
high
high
type from Th2 to Th1
Migratory responsiveness to
cells. Kalinski comlymph node signals
absent/low high
high
ments on the inherent
Th1/CTL-inducing function
low
high
very high
flexibility of Th2 cells,
CTL: cytotoxic T lymphocyte; DC: dendritic cell; DC1: cytokine-matured and NK-matured;
pointing out that use
NK: natural killer cell; Th: T helper.
*Immature DCs can produce high IL-12 levels with the presence of proper co-stimulatory
of the appropriate
factors and absence of IL-12–suppressive factors.
(Revised from Table 1 in P. Kalinski et al. Expert Opin Biol Ther., 2005;5, p.3; reprinted
antigen-presenting
with permission.)
cell after priming can
www.dermatologyfoundation.org
DF
DERMATOLOGY
FOCUS
A PUBLICATION OF THE
DERMATOLOGY FOUNDATION
Sponsored by
Medicis, The Dermatology Company
®
Editors-in-Chief
David J. Leffell, MD
Professor of Dermatology
Yale School of Medicine, New Haven, CT
Christina Herrick, MD, PhD
Asst Professor of Dermatology
Yale School of Medicine, New Haven, CT
Executive Director
Sandra Rahn Benz
Communications Manager
Susan K. Schaefer
Please address correspondence to:
David J. Leffell, MD &
Christina Herrick, MD
Editors, Dermatology Focus
c/o The Dermatology Foundation
1560 Sherman Avenue
Evanston, Illinois 60201
Tel: 847-328-2256 Fax: 847-328-0509
e-mail: dfgen@dermatologyfoundation.org
Published for the
Dermatology Foundation by
Robert Goetz
Designer, Production
Sheila Sperber Haas, PhD
Managing Editor, Writer
This issue of Dermatology Focus is distributed
without charge through an educational grant from
Medicis, The Dermatology Company®.
The opinions expressed in this publication
do not necessarily reflect those of the
Dermatology Foundation or
Medicis, The Dermatology Company®.
© Copyright 2006 by the Dermatology Foundation
repolarize the immune response, “suggesting additional possibilities for the therapeutic induction of Th1 responses.”
CD8+ T Cells and NK Cells—
Novel Collaborators in
Promoting Type 1 DC
CD8+ T cells and NK cells are generally
regarded only as effector cells. CD8+
T cells, a compartment of cellular immunity, attack intracellular pathogens. NK cells
belong to the innate immune system and
are known for their ability to kill transformed or infected cells. Kalinski had
begun to make other associations that
pointed in a new direction. Once he had
identified the critical role of IFN- in the
maturation of IL-12–producing DC, he
made a connection with NK production of
IFN- during infections and with the potential of CD8+ T cells to produce it. Contact
(Continued on page 7)
3
DF Holding Focus
$5 Million in Annual Research Awards Allocation By 2008
In 2003, the Dermatology Foundation challenged the specialty
to join in working toward more adequately funding dermatologic
research through allocations of $5 million per year. Since that
time, allocations have grown from $2.7 million in
“The DF has
2003 to $3.5 million in 2005. This $800,000 growth
always been about
people,
and the future.
is greatly attributed to the increased membership
The Foundation invests
support of dermatologists and other individuals in
your contributions in
the emerging leaders
the dermatologic community.
Research Awards Program
“Dermatology
has become such a
dynamic specialty that
we must be prepared to
meet future needs we
cannot yet envision.”
Increasing Resources
throughout medical and
surgical dermatology—
the people whose
careers will continue to
improve patient care.”
$5 Million/Yr.
Bruce U. Wintroub, MD,
DF President
$3.5 Million/Yr.
Current
Future
On the following pages, we recognize dermatologists
who have made new leadership commitments to more fully expand
DF funding of research and ensure dermatology’s future.
To increase your own participation,
contact the Dermatology Foundation by calling
(847) 328-2256 or go to the membership page at
www.dermatologyfoundation.org
DF
Shaping the Future of Dermatology
4
Dermatology Foundation
Individual Giving Continues to Grow in Support
of Stronger Future for Dermatology
F I T Z PAT R I C K
DF
Six Rise to the Top in Personal Financial
Commitment Through Fitzpatrick Legacy Fund
Each making a commitment of $100,000, members
of the Fitzpatrick Legacy Fund personally commit
LEGACY FUND to adequate funding for research in dermatology. They
will lead the way to an annual DF research award allocation of $5 million within the next three years. The Board of Trustees
thanks each of the current members below for their generous support.
Fitzpatrick Legacy Fund pledges of $100,000 can be paid in minimum annual payments
of $20,000 over as many as five years. Contributions may be made by cash, credit card,
or gifts of appreciated stock either annually or on a quarterly basis throughout the year.
Anonymous Donor
James J. Leyden, MD
Jonah Shacknai
Charles W. Stiefel
Eugene J. Van Scott, MD
Ruey J. Yu, PhD, OMD
Annenberg Circle Membership
Continues to Climb
Dermatologists and other individuals concerned about dermatology’s future emerge each year as leaders in the specialty
through membership in the Annenberg Circle. Now more than
300 members, the Annenberg Circle has been the backbone of
individual giving's growth at the Dermatology Foundation over the past few years.
Young Leaders (those joining the Annenberg Circle or the Leaders Society
during the first five years out of residency) are in BOLD.
Annenberg Circle members receive credit for as much as $10,000 in past Leaders
Society giving toward their $25,000 pledges. Membership pledge payments may be made
annually or quarterly in the form of cash, credit card charges, or gifts of appreciated stock.
(As of December 13, 2005)
Susan K. Ailor, MD
Matthew D. Barrows, MD
David E. Biro, MD
Jean L. Bolognia, MD
Karen E. Burke, MD, PhD
Jennifer C. Cather, MD
S. Wright Caughman, MD
Mark G. Cleveland, MD, PhD
David N. Flieger, MD
Michael J. Franzblau, MD
www.dermatologyfoundation.org
Maria C. Garzon, MD
Lillian R. Graf, MD
James J. Herrmann, MD
Nathan R. Howe, MD, PhD
Stuart I. Jacobs, MD
Arnold W. Klein, MD
Stephen B. Levitt, MD
Jennifer M. McNiff, MD
John C. Moad, MD
Marcy Neuburg, MD
Peter B. Odland, MD, PS
Desiree Ratner, MD
Alain H. Rook, MD
William S. Sawchuk, MD
John J. Schmidt, MD
Joseph J. Shaffer, MD
David A. Spott, MD
Paul A. Storrs, MD
James L. Troy, MD
W. Harrison Turner III, MD
Patrick Walsh, MD
Scott Zahner, MD
5
New Leaders Society Members
Respond to Call for Leadership Support
NEW YORK
Making leadership gifts of $1,500 or more, over 200
dermatologists and other individuals concerned about
adequate funding for dermatologic research have
added their names to the Leaders Society Roster in
2005. Among them are Young Leaders, dermatologists
joining the Leaders Society within five years of
finishing residency (denoted in the list in Bold type).
As of December 13, 2005
ALABAMA
Robert E. Jones, MD
Steve L. Mackey, MD
Donald F. Thompson, MD
CALIFORNIA
Marina A. Ball, MD
Frederick Beddingfield III, MD
Ralph T. Behling, MD
Eileen Crowley, MD, PhD
Linda M. Globerman, MD
Timothy M. Jochen, MD
Derek H. Jones, MD
Suzanne L. Kilmer, MD
Isaac Neuhaus, MD
Ronald E. Reece, MD
Karen R. Simpson, MD
Gaetano Zanelli, MD
COLORADO
David L. Hurt, MD
Brett K. Matheson, MD
CONNECTICUT
Ronald S. Jurzyk, MD
DISTRICT OF COLUMBIA
Beverly A. Johnson, MD
FLORIDA
Joseph A. Arena, MD
Monica K. Bedi, MD
Kenneth R. Beer, MD
Lisa M. Castellano-Howard, MD
James B. Connors, MD
Garry B. Gewirtzman, MD
Richard S. Greene, MD
Michael S. Henner, MD
Stephen N. Horwitz, MD
Kathleen W. Judge, MD
J. Matthew Knight, MD
Ronald C. Knipe, MD
Adele A. Moreland, MD
Mark S. Nestor, MD, PhD
Layne D. Nisenbaum, DO
Jeffrey D. Parks, MD
Harold S. Rabinovitz, MD
Marta I. Rendon, MD
Richard M. Rubenstein, MD
Stanley V. Schwartz, MD
6
Joseph F. Seber, MD
David M. Sharaf, MD
Sharon Stokes, MD
Thomas J. Sultenfuss, MD
Jennifer L. Vesper, MD
Joel M. Wilentz, MD
Daniel J. Wolf, MD
GEORGIA
Linda M. Benedict, MD
Leslie C. Gray, MD
John D. Kayal, MD
Candance K. Kimbrough-Green, MD
David B. Pharis, MD
Kevin L. Smith, MD
Nhu-Linh T. Tran, MD
Stewart E. Wiegand, MD
HAWAII
Wayne H. Fujita, MD
IOWA
Richard K. Scupham, MD, PhD
ILLINOIS
Wayne J. Blaszak, MD
James B. Grossweiner, MD
Nancy C. Lichon, MD
Vladimir V. Panine, MD
Melanie Zahner, MD
INDIANA
Robert H. Huff, MD
Brian J. Williams, MD
KANSAS
Joseph E. Gadzia, MD
Matthew P. Shaffer, MD
MASSACHUSETTS
Marie-France Demierre, MD
Kay S. Kane, MD
Stephen O. Kovacs, MD
Brian W. Lester, MD
Paul Nghiem, MD, PhD
Thomas E. Rohrer, MD
Valori D. Treloar, MD
MARYLAND
Elizabeth M. Burke, MD
Anthony A. Gaspari, MD
Grace F. Kao, MD
Margaret A. Weiss, MD
MICHIGAN
Richard J. Ashack, MD
Karen L. Chapel, MD
Linda C. Chung-Honet, MD
Michael A. Dorman, MD
S.L. Husain Hamzavi, MD
Martin E. Tessler, MD
Thomas P. Waldinger, MD
William F. Weston, MD
Yuelin Xu, MD
Mary Yurko, MD, PhD
MINNESOTA
Michael J. Ebertz, MD
MISSOURI
Darrell Griffin, MD
MONTANA
Charles T. Burton, MD
Gail A. Kleman, MD
NORTH CAROLINA
KENTUCKY
Sue Ellen Cox, MD
Marvin E. Bishop, MD
W. Dean Henrichs, MD
John L. Buker, MD
James B. Patterson, MD
Laurie G. Rendleman Massa, MD Elizabeth Faircloth Rostan, MD
Michael W. McCall, MD
David S. Rubenstein, MD, PhD
Mark J. Zalla, MD
Jon C. Ter Poorten, MD
Val Pierre Vallat, MD
LOUISIANA
NEW JERSEY
John B. Brantley, MD
Laurie H. Harrington, MD
Deborah C. Hilton, MD
Sharon S. Meyer, MD
Maureen A. Olivier, MD
William F. Cosulich, MD
Sharon A. Galvin, MD
Melvin S. Gruber, MD
Jerry Rothenberg, MD
Marc R. Avram, MD
Rena S. Brand, MD
Michael S. Cohen, MD
David Cooper, MD, PhD
Daniel R. Foitl, MD
Paul J. Frank, MD
Francesca J. Fusco, MD
Edward R. Heilman, MD
Rosemarie Ingleton, MD
Eileen K. Lambroza, MD
Vicki J. Levine, MD
Cynthia A. Loomis, MD, PhD
Julian M. Mackay-Wiggan, MD
Timothy D. Mattison, MD
Janet A. Moy, MD
Laurie J. Polis, MD
Jeffrey M. Weinberg, MD
Michael B. Whitlow, MD, PhD
Gladys H. Telang, MD
Caroline S. Wilkel, MD
SOUTH CAROLINA
Marguerite A. Germain, MD
SOUTH DAKOTA
Lycia A. Scott, MD
TENNESSEE
Robert L. Jackson, MD
Julie M. Pena, MD
Raymond J. Wesley, MD
TEXAS
Kent S. Aftergut, MD
Mary E. Archer, MD
Angela G. Bowers, MD
Michael W. Braden, MD
Vivian W. Bucay, MD
David F. Butler, MD
Holly H. Clark, MD
OHIO
Lucius P. Cook, MD
Neera Agarwal-Antal, MD
Steven A. Davis, MD
G. Scott Drew, DO
Kevin J. Flynn, MD
Bruce P. Guido, MD
Aubrey C. Hartmann, MD
Curtis W. Hawkins, MD
Richard H. Hope, MD
Paul G. Hazen, MD
Leslie S. Ledbetter, MD
Samir B. Patel, MD
Lester F. Libow, MD
Patrick L. Shannon, MD
Carolyn B. Lyde, MD
Judith J. Walker, MD
Denise W. Metry, MD
Melinda J. Woofter, MD
Jerold D. Michaelson, MD
OKLAHOMA
Stephen Miller, MD
Gregory A. Nikolaidis, MD
Mark D. Lehman, MD
Robert L. Ochs, MD
OREGON
Brent R. Paulger, MD
Jay Y. Park, MD
F. Charles Petr, Jr, MD
Curtis T. Thompson, MD
Howard A. Rubin, MD
Dale G. Schaefer, MD
PENNSYLVANIA
Michael H. Simpson, MD
Ercem S. Atillasoy, MD
Lori D. Stetler, MD
Robert Bitterman
Premalatha Vindhya, MD
Jacqueline M. Junkins-Hopkins, MD
Mark B. Weinstein, MD
Michael S. Lehrer, MD
Renee J. Mathur, MD
UTAH
Regis W. McHugh, MD
John S. Blake, MD
Andrew K. Pollack, MD
Douglass W. Forsha, MD
Stephen M. Purcell, DO
VIRGINIA
Michael S. Rabkin, MD
Hilary L. Reich, MD
Howard D. Rosenman, MD
John T. Seykora, MD, PhD
Marion M. Vujevich, MD
Richard D. Wortzel, MD, PhD
RHODE ISLAND
Michael A. Bharier, MD
M. Kathleen Carney-Godley, MD
Vincent Falanga, MD
Nomate Kpea, DO
Thomas P. Long, MD
Charles J. McDonald, MD
Jennie J. Muglia, MD
Moses Albert, MD
Allison K. Divers, MD
Lawrence J. Finkel, MD
VERMONT
Daniel P. McCauliffe, MD
WASHINGTON
Daniel B. Dietzman, MD
WISCONSIN
Bradley T. Straka, MD
U.S. MILITARY
Keira Barr, MD
Dermatology Foundation
dermatitis, involving a Th1 response, has a
substantial CD8+ cell infiltrate. Kalinski also
knew that atopic dermatitis—a Th2 pathology—involves no CD8+ T cells and NK cells
only minimally, and some patients have a
deficit in NK cell function. In general, most
Th1-predominant pathologies involve CD8+
T cells and/or NK cells. They are either
absent in a Th2 pattern, or they suppress it.
Integrating these facts with observations
from other labs led him to suspect an unacknowledged helper role for these cells—that
they interact with DC, with Th cells, and with
each other to help polarize DC1 cells and
establish a Th1 immune response. If so, this
would expand the useful tools available for
constructing an effective cancer vaccine.
Kalinski’s research group carried out a
series of experiments to test his hypothesis.
To observe CD8+ T cells, they harvested
and cultured immature DCs, stimulating
(pre-activating) some of them overnight
with TNF-. They co-cultured various cell
combinations that included: pre-activated
DCs and naive Th cells with or without
naive CD8+ T cells, with or without various
cytokine stimulants, with or without various
antigens. Some were transwell experiments,
in which a small-pore membrane separates
the different cell populations but permits
their expressed cytokines to cross through.
Kalinski’s team was able to show that naive
CD8+ T cells—unlike naive Th cells—are able
to produce IFN- at the earliest points in their
priming. Their unique ability to produce this
necessary co-factor for inducing DCs to
express bioactive IL-12 when interacting
with naive Th cells means that—when appropriate antigenic peptides are present—the
two types of T cells synergize in enhancing
this IL-12 production, and thus in promoting
primary Th1 responses. These observations
confirmed Kalinski’s suspicion of a novel
helper role for CD8+ T cells, which he
believed “may have implications for the
design of vaccination strategies against
melanoma and for optimizing the character
of DC-induced anti-tumor responses.”
Studying NK cells for a possible helper
role involved various combinations of young
DC, naive NK (some pre-activated via IL-2),
NK target cells (the leukemia cell line K562),
naive Th cells, CD8+ T cells, Epstein-Barr viral
antigen, and cytokine stimulants that included IL-2, IL-18, and IFN-. Kalinski learned that
NK cell production of IFN- requires the
simultaneous activation by a target cell and
the presence of IFN-. He also learned that
these IFN-–producing NK cells do not
destroy DC, but instead they single-handedly
initiate their maturation as DC1 that robustly
produce the full bioactive IL-12. These NKmatured DC are subsequently able to polarize
www.dermatologyfoundation.org
The ABCs of Immunoresponsiveness
I
L-12—a heterodimer combining the two subunits termed p35 and p40,
and referred to as IL-12p70—is expressed primarily by antigenpresenting cells. Production of the complete molecule requires two signals—stimulation from naive T cells carrying the molecule CD40L (L stands
for ligand, as it binds with the CD40 molecule) and the concomitant presence of either IFN- or such pathogen-derived factors as LPS. The IL-12p70
heterodimer (as opposed to just its subunit) is critical for propagating
Th1 immune responses and cell-mediated immunity, and it stimulates NK
cells and CD8+ T cells (also called cytotoxic T lymphocytes, or CTLs).
In contrast, the p40 subunit—either in monomeric form or as a
p40–p40 homodimer—is inactive (the homodimer) or antagonistic to
the IL-12 receptor and cell-mediated immunity. It correlates with
enhanced production of Th2-driving factors that include the classic
immunosuppressants IL-10 and PGE2. Kalinski prefers to call this
molecule IL-12RA (IL-12 receptor antagonist) instead of IL-12p40. IL-12RA
overproduction has been documented in several tumor models and in
chronic inflammatory states, and as an early event in UV-induced
immunosuppression. The presence of IL-12p70, then, is essential in
ensuring an effective anti-cancer vaccine, and IL-12RA should be avoided.
Priming is the process by which antigen-specific T cells evolve
from their naive state—before they have ever experienced antigen—to
the point at which they are ready for action. “For antigen-specific T
cells, priming is the most important decision—or moment,” Kalinski
says. The naive T cell travels to its respective lymph node, remaining
there until it encounters an antigen-carrying DC. The T cell–DC interaction enables it to proliferate, clonally expand, and then acquire its
effector abilities. This includes expression of the specific chemokine
receptors that now enable it to leave its lymph node and respond to
come-hither signals from inflamed tissue. In the tissue, after the effector phase of the immune response most of the T cells die, and those
remaining persist as memory cells.
Th1—T helper cells (also referred to as CD4+ T cells) with a type 1
phenotype. They are induced by the bioactive form of the cytokine IL-12,
and then induce cell-mediated immunity once they leave the lymph node
by activating cytotoxic and phagocytic functions in effector cells (CTLs,
NK cells, macrophages).
Th2—T helper cells (also referred to as CD4+ T cells) with a type 2
phenotype. They are induced in the absence of IL-12p70, and then induce
humoral immunity—producing cytokines that support B-cell production
of antigen-specific antibodies—while also actively suppressing the
induction of Th1 cells.
naive Th cells to Th1 cells and induce antigenspecific, IFN-–producing CD8+ T cells, even
when the NK–DC interaction occurs before
the DC migrate to the lymph nodes.
Kalinski applies this lesson to understanding the poor effectiveness of spontaneous immune responses against cancer.
“During an early phase of tumor growth, NK
cells can naturally contribute to the elimination of transformed tumor cells,” he says, “but
due to the absence of a second, eg, IFN-–
dependent, signal, the NK cells are not
induced to exert any ‘helper’ activity. Thus
they do not activate or polarize local DC and
so cannot support the development of tumorspecific type 1 immunity, which results in the
eventual loss of control over tumor growth.”
Integrating these observations,
Kalinski speaks of the positive feedback
loop—involving CD8+ T cells, NK cells, and
Th1 cells—promoting type 1 immunity (see
illustration on page 9). “The most important
implication here is that the appropriate
polarization of Th1 responses can occur
independently of any ‘correct’ recognition
of the character of the pathogen,” he points
out. Looking ahead to the impact of this
new awareness on redesigning the cancer
vaccine, Kalinski explained at the time that
“the current observations suggest that
increasing the availability of IFN- at the
tumor site, promoting the interactions of
vaccine-carrying DC with NK cells, and/or
(Continued on page 9)
7
“The DF identifies, encourages,
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A recent past president
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surgery, and
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Dermatologic Surgeon
Encourages Peers to Join DF
8
Dermatology Foundation
using activated NK cells or their soluble
products to modulate DC ex vivo before
their use as a vaccine may constitute effective strategies in the immunotherapy of
cancer patients.”
Final Pieces
After Kalinski arrived at the University
of Pittsburgh from Amsterdam, one of his
first efforts was the successful culture of
effective type 1 DC in a serum-free environment, in preparation for clinical testing of a DC-based cancer vaccine. It had
been a highly frustrating 3-year search for
the right formula, which ultimately combined IL-1, TNF-, IFN-, IFN-, and the
synthetic double-stranded RNA polyinosinic:polycytidylic acid (p-I:C), an agonist
of Toll-like receptor 3 that induces the
production of several interferons. Kalinski
terms the result DC1s. For ability to activate and expand melanoma-specific CD8+
T cells in vitro, this newest mature DC population dramatically outperforms DC that
represent the current gold standard in
DC-based cancer vaccines—DC matured
with PGE2 instead of IFN-. As Kalinski
has demonstrated, the immune response
induced by PGE2-matured DC does not
involve the cellular behavior required
against a tumor. As part of this series of
experiments, Kalinski compared two
groups of CD8+ T cells after their sensitization to three melanoma-associated antigens: MART-1, gp100, and tyrosinase. One
group of CD8+ T cells was sensitized via
his DC1s, the other by the current PGE2matured DC. Just a single round of exposure to his DC1s induced up to 40-fold
more long-lived antigen-specific CD8+ T
cells (see graph below). In addition to this
highly effective induction of large numbers of functional cytotoxic T cells,
Kalinski has preliminary data indicating
their ability to enter the tumor and kill it.
Number of Ag-specific
cells/1x105 CD8+ T cells
600
1000
Total Responses
Positive feedback between NK cells and DC1s. Activated NK cells induce activation of DC1s and
promote their ability to produce the cytokines that drive a Th1 immune response. These DC1s also produce
additional factors that enhance NK cell functions. Their successful cooperation can be supported further by
cytokines produced by other cells. (MDC: myeloid DC; PDC: plasmacytoid DC; IPC: interferon-producing cell.)
(Reprinted with permission from Expert Opin Biol Ther. 2005;5:p.5.)
Despite the indications that TNF- and
IFN- are key mediators of the DC activating
and polarizing activity of NK cells, Kalinski
is convinced that additional factors are likely to be involved. So he continues to search.
Most recently, he and his research team
have discovered the value of IL-18, which
provides the perfect influence for ensuring
NK cells that commit to a life of helping
rather than killing, and display high
migratory responsiveness to lymph nodeassociated chemokines (see photos on
cover). They produce substantial amounts
of IFN- when they are exposed to DC- or
Th-related signals, and show a potent ability to promote IL-12p70 production by DCs
and the consequent development of Th1
immune responses (see graphs on page
10). IL-18 is the sole NK-activating factor
able to achieve this, and—logically—it is
blocked by PGE2.
Mart-1 (27-35)
gp100 (154-162)
gp100 (209-217)
Tyrosinase (368-376)
500
300
0
0
sDC
sDC
DC1
DC1
DC1 superior melanoma response. DC1 sensitizes far
more CD8+ T-cells against melanoma antigens than the current
“gold standard” DC (sDC), seen in representative results for a
patient with stage IV disease. Inset: total number of melanoma
antigen-specific CD8+ T cells. (Reprinted with permission from
Cancer Res. 2004;64:p.5936.)
www.dermatologyfoundation.org
The Third Generation
DC-Based Vaccine:
DC1s for Melanoma, CTCL
The first generation of
melanoma vaccines had focused
on providing melanoma antigens,
or signal one. The next generation
of vaccines took into account the
importance of appropriate co-stimulation as the necessary second signal in achieving vaccine efficacy.
And now the third generation is
designed to include the essential
signal three, using DCs tailored to
launch an effective anti-tumor
response characterized not only
by its high magnitude—but also by
its optimal cancer-fighting character.
Kalinski works closely with the groups
led by John Kirkwood, MD, a pioneer in the
clinical application of interferons and the
current head of the UPCI Melanoma
Center, and by Louis Falo, MD, PhD, chair
of the University of Pittsburgh Department
of Dermatology, who has long been
committed to developing an effective
melanoma vaccine (see 1997; Vol. 15, No.
4). In addition to organizing a trial of
Kalinski’s DC1-based vaccine for CTCL
patients, Falo recently used the B16
melanoma mouse model for testing this
vaccine’s initial efficacy. He chose the B16
model “because it is a formidable model
tumor for evaluating immunotherapeutic
strategies due to its multiple well-established mechanisms of tolerance induction
and immune evasion. It models the most
challenging tumor escape mechanisms
thus far described for a variety of human
tumors,” Falo observes. It down-regulates
MHC class I molecules and antigenprocessing machinery; produces vascular
endothelial growth factor that inhibits DC
function and T-cell immunity; and produces galectin-1, a negative regulator of
T-cell activation and survival. Regulatory
T cells contribute their own inhibition of
effective CD8+ T-cell responses.
Falo’s team injected DC1s loaded
with B16 melanoma cells into these tumorbearing mice. And despite the resident
tumor’s immune challenges, the DC1s
induced Th1-skewed tumor-specific cells
and achieved a significant reduction in
tumor growth. The anti-tumor immune
response was characterized by tumor9
Secondary Stimuli
No Stimuli
NK Cell Treatment
Control
<<
IL-18
<<
0
IFN-
IL-2
IL-12
<<
1
2
0
2.5
6
<<
0
5
10
0
10
20
IFN- (ng/ml)
Secondary Stimuli
No Stimuli
NK Cell Treatment
Control
<<
IL-18
<<
IL-18+PGE2 (early)
<<
IL-18+PGE2 (late)
<<
0
IFN-
IL-2
<<
1
2
0
IL-12
<<
2
4
0
<<
1
2
0
5
10
IFN- (ng/ml)
IL-18–primed helper NK cells. NK cells treated with IL-18 for 24 h produce high levels of Th1-supportive IFN- on contact with secondary stimuli IL-2, IFN-,
IL-12 (top). IL-18 for 48 h is negated by the simultaneous presence of Th2-driving PGE2 but unaffected when PGE2 is added at 24 h, reflecting the stability of the initial
exposure (bottom). (Reprinted with permission from J Exp Med. 2005;202:p.946.)
specific IFN-–producing T cells and “brisk
tumor infiltrates containing Th1 cells and
macrophages,” Falo says. In addition to
confirming the ability of these polarizing
antigen-presenting cells to overcome the
the B16 melanoma’s profound immune
inhibition, this successful murine model
of ex vivo engineered DC1s now provides
a needed model for aiding continued
vaccine progress.
Kalinski and Kirkwood are about to
begin the first of their melanoma trials in
January 2006. This initial trial will involve
28 patients with advanced melanoma.
Kalinski’s total funding will ultimately allow
the treatment of 93 patients—70 with
melanoma and 23 with colorectal cancer—
and a protocol for prostate cancer is in the
design stage. Falo’s group is beginning a formal trial of this vaccine in advanced CTCL
patients following preliminary observations
of highly encouraging results. These initial
trials all center around the DC1, but a clinical trial using NK-induced DC1s is planned
for the spring of 2006. Kalinski is also working on a way to induce DC1 in vivo. “We
have some very strong mouse data showing
that with our current manipulation of DCs
in vivo, we induce cells with similar functions that dramatically enhance the rate of
tumor rejection.” He adds his hope that
“very soon we will be translating this observation into clinical trials.”
In the trials getting underway now,
one phenomenon that Kalinski is hoping
10
to observe is epitope spreading. This
involves an expansion, by natural processes, of the tumor antigens initially used by
the DC1 cells in the vaccination. He
explains that tumor cells killed by the vaccine-induced immune attack will release
all of their antigenic material, including
highly immunogenic tumor antigens that
had not been part of the vaccine. DCs are
particularly good at picking up antigens
from dead cells. If epitope spreading
occurs, then immune effector cells will
be primed for these additional antigens.
Kalinski says that “based on the data from
Dr. Falo’s initial patients, we expect that
this will take place.”
Primarily, he will be looking for solid
evidence that his third generation vaccine
will successfully overcome the formidable
resistance that melanoma mounts to inhibit immune cells or render them highly dysfunctional. “By removing the dendritic
cells from the context of melanoma, and
culturing them and then instructing them
what to do ex vivo, we hope to bypass this
immune dysfunction by allowing them to
develop into fully potent immunostimulatory cells free of the melanoma-enriched
environment,” Kalinski comments. “We
hope that when we inject them into
patients, they will be able to enter the
lymph node, and then do the job that naturally occurring DCs are unable to do.”
Call For Patients
Kalinski, Falo, Kirkwood, and their
co-workers would welcome patients in
their melanoma and CTCL trials who
come from outside their institution. The
more rapidly they assemble their patient
rosters, the more rapidly they will be
able to assess the efficacy of this third
generation cancer vaccine. Interested
dermatologists can contact Pawel Kalinski
at kalinskip@upmc.edu, and Louis Falo at
lof2@pitt.edu.
Suggested Readings
Kalinski P, Hilkens CMU, Wierenga
EA, et al. “T-cell priming by type 1 and
type 2 polarized dendritic cells: The concept of a third signal.” Immunol Today.
1999;20:561–7.
Kalinski P, Vieira PL, Schuitemaker
JHN, et al. “Prostaglandin E2 is a selective
inducer of interleukin-12 p40 (IL-12p40)
production and an inhibitor of bioactive IL12p70 heterodimer.” Blood. 2001;97:3466–9.
Mailliard RB, Egawa S, Cai Q, et al.
“Complementary dendritic cell-activating
function of CD8+ and CD4+ T cells: Helper
role of CD8+ T cells in the development of
T helper type 1 responses.” J Exp Med.
2002;195:473–83.
Kalinski P, Giermasz A, Nakamura Y,
et al. “Helper role of NK cells during the
induction of anticancer responses by dendritic cells.” Mol Immunol. 2005;42:535–9.
Hokey DA, Larregina AT, Erdos G, et al.
“Tumor cell loaded type 1 polarized dendritic cells induce Th1-mediated tumor
immunity.” Cancer Res. 2005; 65:10059–67. ■
Dermatology Foundation
Focus on Research
(Continued from cover)
health problem just south of us, in
Mexico. Tuberculoid patients (T-lep)—with
a relatively successful immune response
that keeps their infection under control—
lie at one end of the clinical spectrum.
Their few cutaneous lesions contain the
rare presence of Mycobacterium leprae,
and evaluation shows them able to mount
a strong cell-mediated immune response
to this organism. Lepromatous patients
(L-lep) are at the other end, with an ineffective immune response and rampant
infection. Disseminated skin lesions contain large numbers of bacilli. Their
immune response is mediated primarily
through humoral pathways, and their T
cells are selectively unresponsive to M.
leprae. Modlin’s earlier explorations of
these contrasting immune responses
(see 1998; Vol. 17, No. 3) included his
observation that Th1 cytokines (IFN-, IL-12,
IL-18, GM-CSF) dominate the successful
immune response, and Th2 cytokines (IL-4,
IL-10) predominate in disseminated disease. He had also discovered the involvement of the endogenous cell-lysing antimicrobial granulysin as an additional weapon
in successful immune control.
Now that he had identified the
immune response elements that differentiate the clinical presentations in T-lep and
L-lep patients, Modlin wanted to understand how these different cytokines are
regulated—and that is when Toll-like receptors entered the picture.
cell-mediated and humoral immune
responses. “So we knew that mycobacteria
induce IL-12,” Modlin adds, “but we had
no idea at that point how they do it. We
wanted to find out what molecules accomplish this, and by what mechanism.”
Modlin and his co-workers began
their exploration with the more available
M. tuberculosis, breaking it down into
smaller and smaller segments that they
tested against an IL-12–producing human
leukemic monocyte cell line. The initial
round of subcellular components point-
ed to soluble cell wall proteins as responsible for most of the mycobacterium’s
IL-12p40–inducing capacity, the most easily inducible segment of the larger IL-12
molecule (IL-12p70). Fractionating this
soluble cell wall protein component and
purifying its individual constituents singled out two in particular as responsible
for inducing their cultured monocytes to
produce IL-12p40. By far the most potent
of the two was a 19-kD lipoprotein. Its
IL-12–inducing effect was the same in
healthy human monocytes.
TLR2
T-lep
L-lep
TLR1
Toll-like Receptors
“We were trying to understand the factors that influence the Th1 vs the Th2
cytokine response,” Modlin notes. “It was
known that the key factor for inducing a
Th1 cytokine response is IL-12, which is a
powerful signal for generating the Th1 and
cytolytic T-cell responses required to eliminate intracellular pathogens, including
Mycobacterium tuberculosis. We also knew
that people with mutations affecting IL-12
receptor function have an increased susceptibility to mycobacterial infection.
And,” he continues, “IL-12 was known to
be produced by the innate immune system—by dendritic cells (DCs) and monocytes—as a way of influencing the nature of
the adaptive T-cell response, meaning the
specific pattern of cytokines expressed by
the T cells.” Besides causing disease,
mycobacteria had long been recognized
for their powerful ability to augment both
www.dermatologyfoundation.org
T-lep
L-lep
Few TLRs in L-lep lesions. TLR2 was strongly expressed in tuberculoid leprosy lesions (T-lep, top row), but
sparse in lepromatous leprosy lesions (L-lep, 2nd row). TLR1 was also strongly expressed in tuberculoid leprosy
lesions (T-lep, 3rd row), but weakly present in lepromatous leprosy lesions (L-lep, bottom row). (Reprinted with
permission from Nat Med. 2003;9:p.528.)
11
T-lep
L-lep
RR
CD1b
DC-SIGN
L-lep lesions lack antigen-presenting cells. TLR2/1 induces monocyte differentiation to macrophages
(labeled DC-SIGN), which capture bacilli, and DCs (labeled CD1b), which present antigen to induce
adaptive Th1 immunity. Both cell types are abundant in tuberculoid leprosy lesions (T-lep). Lepromatous
lesions (L-lep) contain only macrophages. L-lep patients undergoing reversal reaction (RR) show both cell
types in frequencies that resemble T-lep lesions. (Reprinted with permission from Nat Med. 2005;11:p.658.)
Their next step was to identify the
membrane-bound receptor on responsive
cells that transduces the signal for this
19-kD lipoprotein. “The Toll-like receptors
(TLRs) had very recently been discovered
in humans,” Modlin says. They had been
identified in Drosophila just several years
earlier, and their presence in mammals as
well indicates that the Toll proteins represent a host defense mechanism that has
been conserved over hundreds of millions of years of evolution. In mammals,
TLRs provide the innate immune system
with the ability to react to different classes
of microbial biochemicals and to signal
activation of adaptive immunity.
“TLR2 had been shown to be the
receptor that mediates the response to
lipopolysaccharides,” Modlin says. He
contacted the investigator of that study,
and they established a collaboration to
see if lipoproteins might also trigger TLR2.
Modlin describes six intense weeks of
nonstop experiments, by the end of which
“we had figured out that, in fact, TLR2
clearly was the trigger for microbial
lipoproteins.” He and his colleagues
duplicated this observation with lipoproteins from both Borrelia burgdorferi (the
cause of Lyme disease) and Treponema
pallidum (which causes syphilis), both of
which induced monocyte production of
IL-12 exclusively via TLR2. When a monoclonal antibody for TLR2 was added to the
mix—preventing it from functioning—cultured human monocytes exposed to the
19-kD lipoprotein from M. tuberculosis no
longer produced IL-12.
12
As a side note, the characterization of
TLR2 as the responding molecule for
lipopolysaccharides turned out to be inaccurate. The original preparations were discovered to have been contaminated with
lipoprotein, and the lipopolysaccharide
receptor was eventually—and accurately—
identified as TLR4.
Mouse and Human—
Vive la Différence
Modlin next wanted to know whether
the TLR signaling pathway stimulated by
microbial lipoproteins could be linked to a
known monocyte antimicrobial mechanism. The answer turned out to be a partial
yes, because his observations held only for
mice, not humans.
Modlin and his co-workers looked at
the induction of inducible nitric oxide
synthase (iNOS) and consequent release
of nitric oxide (NO), which was the only
known effective monocyte/macrophage
mycobactericidal mechanism and represents a powerful antimycobacterial
defense mechanism in mice. First they
documented the ability of their 19-kD
lipoprotein, and the comparable lipoprotein from T. pallidum, to impair the viability
of M. tuberculosis in a murine macrophagelike cell line. This activity was abrogated
when a pharmacologic inhibitor of iNOS
was added. Then they used the 19-kD lipoprotein from M. tuberculosis to stimulate
infected macrophages from normal mice,
and from mice lacking TLR2. Macrophages
from normal mice produced NO, and
viability of the intracellular microbes was
substantially diminished. Little happened
in the infected macrophages from the
TLR2-deficient mice—NO production was
marginal, and intracellular organisms were
unaffected.
When Modlin placed M. tuberculosisinfected human monocytes and alveolar
macrophages under the spotlight, once
again the 19-kD protein impaired the intracellular microbes, and—as in mice—the
effect was mediated through TLR2. But the
similarity stopped there. The big surprise
was that TLR2 stimulation failed to activate
the NO pathway. “The presence of TLR2 on
cells of the monocyte/macrophage lineage in lesions of human tuberculosis infection indicates that activation of TLR2
could contribute to host defense at the site
of disease activity,” Modlin points out. But
these results showed that the microbicidal
activity initiated in human cells by TLR2
relies on a mechanism other than NO. This
fundamental difference between the
TLR2-triggered mechanisms in mice and
humans reminds us that observations in
animals represent merely a starting point
for human exploration, not an expectation
of results.
This disconnect between the mouse
and human results sent Modlin on another
successful search, this time for the microbicidal pathway activated in humans
when microbial lipoproteins are recognized by TLR2. Although it is premature
to announce the results, Modlin does
acknowledge at this point that his observations were completely unexpected, and
take his investigations in humans into a
highly unanticipated area of cell function.
The TLR2-triggered pathways in humans
appear to be far more complex than they
had initially appeared.
The LIR Family
Modlin decided to compare the two
forms of leprosy via gene expression profiling as a different approach to shedding
further light on the clinical and immunologic differences between T-lep and L-lep
patients. He collected skin biopsy specimens (6 from T-lep patients, 5 from L-lep
patients) and found that each group clustered together based on a similar gene
expression pattern. This difference was
statistically significant despite the small
patient numbers, with an accuracy that
enabled an unknown patient sample to be
correctly assigned.
Modlin found that genes belonging to
the leukocyte immunoglobulin-like receptor (LIR) family—especially LIR-7—were
significantly up-regulated in L-lep lesions.
(Continued on page 15)
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with kidney disease.
Rx ONLY
DESCRIPTION: Sodium sulfacetamide is a sulfonamide with antibacterial activity while sulfur acts as a keratolytic agent. Chemically sodium sulfacetamide is N-[(4-aminophenyl)
sulfonyl]-acetamide, monosodium salt, monohydrate. The structural formula is:
Na
NH2
SO2NCOCH3 H2O
Each gram of Plexion‚ (sodium sulfacetamide USP 10% and sulfur USP 5%) Cleanser contains
100 mg of Sodium Sulfacetamide USP and 50 mg of Sulfur USP in a cleanser base containing:
Purified Water USP, Sodium Methyl Oleyltaurate, Sodium Cocoyl Isethionate, Disodium
Oleamido MEA Sulfosuccinate, Cetyl Alcohol NF, Glyceryl Stearate (and) PEG-100 Stearate,
Stearyl Alcohol NF, PEG-55 Propylene Glycol Oleate, Magnesium Aluminum Silicate NF,
Methylparaben NF, Edetate Disodium USP, Butylated Hydroxytoluene NF, Sodium Thiosulfate
USP, Fragrance, Xanthan Gum NF, and Propylparaben NF.
Each cloth of Plexion‚ (sodium sulfacetamide USP 10% and sulfur USP 5%) Cleansing Cloths
is coated with a cleanser-based formulation. Each gram of this cleanser-based formulation
contains 100 mg of sodium sulfacetamide USP and 50 mg of sulfur USP. The cleanser base
consists of: Purified Water USP, Sodium Methyl Oleyltaurate, Sodium Cocoyl Isethionate,
Disodium Laureth Sulfosuccinate (and) Sodium Lauryl Sulfoacetate, Disodium Oleamido MEA
Sulfosuccinate, Glycerine USP, Sorbitan Monooleate NF, Glyceryl Stearate (and) PEG-100
Stearate, Stearyl Alcohol NF, Propylene Glycol (and) PEG-55 Propylene Glycol Oleate, Cetyl
Alcohol NF, Edetate Disodium USP, Methylparaben NF, PEG-150 Pentaerythrityl Tetrastearate,
Butylated Hydroxytoluene NF, Sodium Thiosulfate USP, Aloe Vera Gel Decolorized, Allantoin,
Alpha Bisabolol Natural, Fragrance, Propylparaben NF.
Each gram of Plexion SCT‚® (sodium sulfacetamide USP 10% and sulfur USP 5%) contains 100
mg of Sodium Sulfacetamide USP and 50 mg of Sulfur USP in a cream containing: Purified
Water USP, Kaolin USP, Glyceryl Stearate (and) PEG-100 Stearate, Witch Hazel USP, Silicon
Dioxide NF, Magnesium Aluminum Silicate NF, Benzyl Alcohol NF, Water (and) Propylene Glycol
(and) Quillaja Saponaria Extract, Xanthan Gum NF, Sodium Thiosulfate USP, Fragrance.
Each gram of Plexion‚® (sodium sulfacetamide USP 10% and sulfur USP 5%) Topical
Suspension contains 100 mg of Sodium Sulfacetamide USP and 50 mg of Sulfur USP in a
suspension containing: Purified Water USP , Propylene Glycol USP, Isopropyl Myristate NF,
Light Mineral Oil NF, Polysorbate 60 NF, Sorbitan Monostearate NF, Cetyl Alcohol NF,
Hydrogenated Coco-Glycerides USP, Stearyl Alcohol NF, Fragrances, Benzyl Alcohol NF,
Glyceryl Stearate (and) PEG-100 Stearate, Dimethicone NF, Zinc Ricinoleate, Xanthan Gum NF,
Edetate Disodium USP, and Sodium Thiosulfate USP.
CLINICAL PHARMACOLOGY: The most widely accepted mechanism of action of sulfonamides
is the Woods-Fildes theory, which is based on the fact that sulfonamides act as competitive
antagonists to para-aminobenzoic acid (PABA), an essential component for bacterial growth.
While absorption through intact skin has not been determined, sodium sulfacetamide is
readily absorbed from the gastrointestinal tract when taken orally and excreted in the urine,
largely unchanged. The biological half-life has variously been reported as 7 to 12.8 hours.
The exact mode of action of sulfur in the treatment of acne is unknown, but it has been
reported that it inhibits the growth of Propionibacterium acnes and the formation of free fatty
acids.
INDICATIONS: PLEXION Cleanser, PLEXION Cleansing Cloths, PLEXION SCT and PLEXION TS
are indicated in the topical control of acne vulgaris, acne rosacea and seborrheic dermatitis.
CONTRAINDICATIONS: Plexion Cleanser, PLEXION Cleansing Cloths, PLEXION SCT and
PLEXION TS are contraindicated for use by patients having known hypersensitivity to
sulfonamides, sulfur or any other component of this preparation. These PLEXION,® brand
products are not to be used by patients with kidney disease.
WARNINGS: Although rare, sensitivity to sodium sulfacetamide may occur. Therefore, caution
and careful supervision should be observed when prescribing this drug for patients who may
be prone to hypersensitivity to topical sulfonamides. Systemic toxic reactions such as
agranulocytosis, acute hemolytic anemia, purpura hemorrhagica, drug fever, jaundice, and
contact dermatitis indicate hypersensitivity to sulfonamides. Particular caution should be
employed if areas of denuded or abraded skin are involved.
FOR EXTERNAL USE ONLY. Keep away from eyes. Keep out of reach of children. Keep
container tightly closed.
PRECAUTIONS: General - If irritation develops, use of the product should be discontinued
and appropriate therapy instituted. Patients should be carefully observed for possible local
irritation or sensitization during long-term therapy. The object of this therapy is to achieve
desquamation without irritation, but sodium sulfacetamide and sulfur can cause reddening
and scaling of the epidermis. These side effects are not unusual in the treatment of acne
vulgaris, but patients should be cautioned about the possibility.
Information for Patients: Avoid contact with eyes, eyelids, lips and mucous membranes. If
accidental contact occurs, rinse with water. If excessive irritation develops, discontinue use
and consult your physician.
Carcinogenesis, Mutagenesis and Impairment of Fertility - Long-term studies in animals
have not been performed to evaluate carcinogenic potential.
Pregnancy Category C – Animal reproduction studies have not been conducted with
PLEXION Cleanser, PLEXION Cleansing Cloths, PLEXION TS or PLEXION SCT. It is also not
known whether these PLEXION brand products can cause fetal harm when administered to
a pregnant woman or can affect reproduction capacity. These PLEXION® brand products
should be given to a pregnant woman only if clearly needed.
Nursing Mothers - It is not known whether sodium sulfacetamide is excreted in the human
milk following topical use of Plexion Cleanser, Plexion Cleansing Cloths, PLEXION SCT or
PLEXION TS. However, small amounts of orally administered sulfonamides have been
reported to be eliminated in human milk. In view of this and because many drugs are
excreted in human milk, caution should be exercised when these PLEXION brand products
are administered to a nursing woman.
Pediatric Use - Safety and effectiveness in children under the age of 12 have not been
established.
ADVERSE REACTIONS: Although rare, sodium sulfacetamide may cause local irritation.
DOSAGE AND ADMINISTRATION: PLEXION Cleanser: Wash affected areas once or twice
daily, or as directed by your physician. Avoid contact with eyes or mucous membranes. Wet
skin and liberally apply to areas to be cleansed, massage gently into skin for 10-20 seconds
working into a full lather, rinse thoroughly and pat dry. If drying occurs, it may be controlled
by rinsing cleanser off sooner or using less often.
PLEXION Cleansing Cloths: Wash affected areas with cleansing cloth once or twice daily,
or as directed by your physician. Wet face with water. Wet cloth with a little water and work
into a full lather. Cleanse face with cloth for 10-20 seconds avoiding eyes. Rinse thoroughly
and pat dry. Throw away cloth. Do not flush.
PLEXION SCT: Use once daily or as directed by your physician. Wet skin. Apply in a film to
entire face, avoiding contact with eyes or mucous membranes. Wait 10 minutes or until dry.
Rinse thoroughly with water and pat dry.
PLEXION TS: Cleanse affected areas. Apply a thin film of PLEXION TS to affected areas 1 to
3 times daily, or as directed by a physician.
HOW SUPPLIED: Plexion‚® (sodium sulfacetamide 10% and sulfur 5%) Cleanser is available
in 6 oz. (170.3 g) tube (NDC 99207-741-06) and 12 oz. (340.2 g) bottle (NDC 99207-741-12).
Plexion‚® (sodium sulfacetamide 10% and sulfur 5%) Cleansing Cloths are available in boxes
of 30 cloths (3.7 g) (NDC 99207-745-30). Plexion SCT‚® (sodium sulfacetamide 10% and sulfur 5%) is available in a 4 oz. tube (NDC 99207-744-04). Plexion‚® (sodium sulfacetamide
10% and sulfur 5%) Topical Suspension is available in 30 g tube (NDC 99207-743-30).
Store at 15º - 25ºC (59º - 77ºF).
Manufactured for:
MEDICIS, The Dermatology Company®
Scottsdale, AZ 85258
by: Tapemark
West St. Paul, MN 55118
Prescribing information as of Jan 2004
Patent Pending
74530-08C
References: 1. Data on file, MEDICIS® Pharmaceutical Corporation.
© 2004 MEDICIS® Pharmaceutical Corporation
PLX04031
Another lab had found a reciprocal
expression pattern of TLR and LIR-7 in leprosy lesions, prompting Modlin to carry
out functional studies in monocytes. He
learned that LIR-7 suppresses innate host
defense mechanisms in two different
ways. It shifts cytokine production from
IL-12, which induces cell-mediated immunity, toward IL-10, which suppresses it.
LIR-7 also blocks the antimicrobial activity
triggered by TLRs.
“We were able to define gene expression patterns associated with an ongoing
immune response in these lesions,”
Modlin says. “Our data support the view
that modern genomics can reveal the sets
of genes that correlate with protective
responses or inappropriate responses
leading to disease progression and tolerance, and this provides unanticipated
insights into pathogenesis and targets for
therapy. And,” he adds, “the development
of reliable biomarkers may improve
patient diagnosis and classification.”
TLRs in Human Leprosy
Before long, TLR research provided
awareness of a more extensive TLR family
and a more precise understanding of their
specificity in mediating responses to
defined bacterial ligands. This included
the realization that TLR2 could join with
others to function as a larger unit. TLR2
alone and as a heterodimer with TLR1
mediates the response to microbial triacylated lipoproteins, TLR3 to double-stranded viral RNA, TLR4 to lipopolysaccharide,
TLR5 to bacterial flagellin, the TLR2–TLR6
heterodimer to diacylated lipopeptides,
TLR7 and TLR8 to imidazoquinolines, and
TLR9 to bacterial CpG DNA sequences.
Modlin used leprosy to investigate the
expression and activation of these TLRs
and relevant mechanisms of innate and
adaptive immunity.
He and his research team used human
cell lines that expressed each of the individual TLRs, or each of the heterodimers
involving TLR2 (TLR2/1, TLR2–TLR6,
TLR2–TLR10), and activated them with
killed M. leprae. Among the homodimers,
only TLR2 was able to mediate responsiveness toward this mycobacterium. Among
the heterodimers, co-expression of TLR1
dramatically enhanced this impact.
Their next step was to search the M.
leprae genome for putative lipoproteins,
which led them to a pool of 31 candidates.
Two were selected for further study. The 19kD ML1966 shares substantial amino acid
sequence identity with the 19-kD lipoprotein from M. tuberculosis that Modlin had
www.dermatologyfoundation.org
identified in his initial research. ML0603
was selected because of direct evidence
that it triggers cytokine release in monocytes. Each lipopeptide stimulated the
release of IL-12p40 in both freshly harvested human monocytes and monocytederived dendritic cells from healthy
donors. This activation was blocked when
TLR2 was neutralized using antibody.
The next step took a reverse perspective, looking to see if the type 1 cytokines
present in T-lep lesions and the type 2
cytokines found in L-lep lesions are able to
influence TLR2/1 mediated activation of
monocytes and DCs from normal human
cells. Without M. leprae stimulation, these
cytokines had no effect. Without cytokines,
M. leprae had no effect. Then Modlin stimulated these cells with the 19-kD lipopeptide from M. leprae and either type 1
cytokines (IFN-, IL-12, IL-18, GM-CSF) or
type 2 cytokines (IL-4, IL-10). Type 1
cytokines enhanced this lipopeptide’s ability to trigger monocyte release of the
immune-stimulating cytokine TNF-. The
type 2 cytokines substantially inhibited
this. IFN- had the same up-regulating
effect on lipopeptide-induced release of IL12p40 from DCs, which—again—was inhibited by IL-4 and IL-10. Modlin also learned
that the cytokine milieu influences the density of TLR2 surface expression. The type 2
cytokine IL-4 substantially decreases the
TLR2 presence on monocytes and DCs. In
contrast, type 1 cytokines up-regulate the
expression of TLR1. “It is well known that
the innate immune response serves an
instructional role in shaping the adaptive
immune response,” Modlin points out.
“And our data here indicate that the adaptive immune response—by releasing T-cell
cytokines that regulate TLR activation—can
also influence the magnitude of the innate
immune response.”
The current flows in both directions.
And this raises one of those “which came
first” issues. On the one hand, an activated
TLR2 induces the expression of type 1
cytokines in the cell. On the other, the presence of type 1 cytokines in the cell up-regulates the presence of TLR2 and enhances
its activities. Where did it start? “We don’t
yet know the answer,” Modlin says. “For a
disease like leprosy, which has such a long
incubation time, no one knows whether
TLR2, and thus IL-12, have to come first to
get a Th1 immune response, or whether
the presence of a small Th1 population
will help induce an effective TLR2 presence, or whether there is actually some sort
of synergistic amplification of this process.”
Whatever the explanation turns out to be,
Modlin sees potential therapeutic benefit
from recognizing that the immune
response in leprosy is shaped in part by the
influence of the local cytokine environment on the regulated expression and activation of TLR2 and TLR1. “This means it
should be possible to design therapeutic
agents that regulate TLR expression and
activation.” The application is far broader
than leprosy.
When Modlin and his research team
turned to cells from leprosy patients, measuring the amount of TLR2 and TLR1 expression on peripheral monocytes was unproductive. TLR2 levels were the same in T-lep
and L-lep patients and TLR1 was undetectable. Assessing circulating monocytes
and DCs for IL-12p40 production after
exposing them to the 19-kD lipopeptide still
showed no difference between the two
groups. In circulating blood, therefore,
both T-lep and L-lep patients can mount a
functionally equivalent TLR2/1 response.
The critical step was examining
cells taken from lesional skin, the site of
disease activity, where “the battle between
host immune response and microbial
pathogens in leprosy is enjoined,” Modlin
comments. “We wanted to determine
whether the expression of TLR2 and TLR1
in these lesions correlates with the local
cytokine pattern characteristic of the different forms of this disease.” Biopsy specimens revealed notable differences in frequency and distribution (see photos on
page 11). Both TLR2 and TLR1 were strongly expressed in T-lep lesions, but only
weakly expressed in L-lep lesions. Most of
the cells expressing TLR2 were of monocyte/macrophage lineage, with DCs the
remainder. Expression of TLR1 co-localized with TLR2, indicating that most
cells expressed the TLR2/1 heterodimer.
Leprosy patients with a competent
immune response were clearly shown to
express substantially more TLR2s and
TLR1s, and on the appropriate cells, compared to patients at the other end of
the spectrum.
How TLR2 Orchestrates an
Effective Immune Response
The innate immune system has two
clearly distinctive functions, triggering
both direct and indirect effector pathways
to combat microbial pathogens. It mediates the immediate host response by acting
directly to localize the invading pathogen
so it can be destroyed by antimicrobial
mechanisms. It acts indirectly—through
cytokine release and up-regulation of
(Continued on page 18)
15
Dermatology Foundation Annual Awards
Honor Outstanding Dermatologists
The Dermatology Foundation will recognize two of dermatology’s leaders at
its Annual Meeting on March 4, 2006, in San Francisco. This tradition of honoring
dermatology’s formative leaders, teachers, and role models began in 1971
with the Clark W. Finnerud Award to recognize an exemplary private practitioner
who also epitomizes commitment to the specialty as a part-time teacher.
The Practitioner of the Year Award, initiated in 1976, recognizes dermatologists
dedicated to the highest levels of clinical care.
2005 Clark W. Finnerud Award: Paul S. Russell, MD
Dr. Russell, Clinical Professor Emeritus,
both the challenge of the bright young people
Oregon Health & Science University, Portland,
coming into the residency program every year,
OR, will be honored for his long and distinand teaching the medical students as well,”
guished career in dermatology combining
Dr. Russell says.
dedication to patients in a private practice
He went into private practice in 1969 with
setting with a devotion to teaching.
Frederick A. J. Kingery, MD. Their practice
was devoted to medical dermatology, and Dr.
He chose the specialty of dermatology only
Russell observes that they always felt lucky
after he had become a practicing physician,
to be practicing the specialty of
presiding over his family practice in
dermatology.
the small Texas town of Levelland
where he had grown up. “After six
Commenting on Dr. Russell’s
years of delivering babies, fixing
contributions as a clinical educator,
broken bones, sewing up car
Neil A. Swanson, MD, Chair of
wrecks, and doing a little bit of
Dermatology at OHSU—noting
everything else, I realized that I did
that “Paul has been part of the
not want to continue doing that long
clinical faculty here since he
term,” he recalls. “I had had suffibegan practicing in Portland in the
cient experience with dermatology
late ‘60s”—adds that “he was the
during those six years to know that
prime organizer of Grand Rounds
for the department and is a superb
I enjoyed it.” Dr. Russell and his late
Paul S. Russell, MD
teacher. He continues to chair
wife, Tomi Jean, chose Portland,
the weekly clinical morphology conference.”
OR, as the ideal place to spend his residency
years and were delighted with his acceptance
Throughout his career, Dr. Russell found
in the department at Oregon Health & Science
time for leadership roles in the Dermatology
University. They never left.
Foundation, American Academy of
Dermatology, the American Dermatological
Dr. Russell owes his initial motivation to
Association, and the Accreditation Council for
volunteer for part-time teaching to Dr. Walter
Graduate Medical Education.
Lobitz, then chair of the Department of
Dermatology. “It was always his teaching that
Dr. Russell comments that “I went into partdermatologists should give back to the spetime volunteer teaching because I enjoyed it,
cialty, and I found that very appealing,” he
and I thought that giving something back to
explains. “I wanted to make a contribution to
my specialty was the proper thing to do. I had
my specialty. Then I discovered that I really
no thought of gaining recognition, and I am
enjoyed my time at the medical school—
honored and delighted to receive this Award!”
16
Dermatology Foundation
2005 Practitioner of the Year Award: W. Harrison Turner III, MD
Dr. Turner has been affiliated with the
produced a standard-setting successful result.
Greensboro, NC, dermatologic community
“That was a time of doom and gloom,” he
since completing his residency at Duke
recalls. “The fear was that the gatekeeper
Medical Center, Durham, in 1976, and he
would eliminate our specialty.” The PPO type
has been a central figure in the wider health
of format they developed maintained direct
care and general communities there for
patient access to specialists. Dr. Turner headalmost as many years.
ed the organization until 1995
and chaired the AAD’s Managed
Ironically, gastroenterology was
Health Care Committee from
Dr. Turner’s initial goal after receiv1990 to 1993, remaining as
ing his MD from the Medical
consultant for two more years.
College of Virginia in 1968. His
medical residency was scheduled
Dr. Turner has also been an
to begin in 1972, after his internabiding presence in the life of
ship at MCV and three years in
Greensboro itself and received
the Air Force. “But on my military
Greensboro’s Distinguished
base in England, I was temporarily
Citizen Award in 2003. The
assigned to triage dermatology
honor of being the DF’s 2005
W.
Harrison
Turner
III,
MD
patients once each week. This
Practitioner of the Year joins
included afternoon rounds and
that award as “the two things in
patient presentation at Cambridge at the time
my life I am most proud of,” Dr. Turner says.
that noninfectious cutaneous diseases were
In nominating Dr. Turner, Elise Olsen, MD,
just beginning to be approached in precise
a colleague at Duke University Medical
immunologic rather than descriptive terms.
Center, calls Dr. Turner “a remarkable man ...
I was stimulated by dermatology and fascinatan excellent physician, both in his scope of
ed with this view—and I fell in love with the
knowledge and in his compassionate care of
T cell!” Dr. Turner recalls.
his patients. He is an amazing example of a
He returned to the U.S. and was introduced well-rounded dermatologist and a credit to
to Dr. J. Lamar Callaway, chief of dermatology
our profession.”
at Duke University. This meeting was the
clincher. Dr. Turner did his dermatology resi2005 Lifetime Career
dence under Dr. Callaway, who remains an
inspiration for him.
Educators Named
One of the pleasures that Dr. Turner finds
At its March 4, 2006 Annual Meeting,
in his practice is his patients. They span all
the Dermatology Foundation will also honor
ages, and “once you see one member of a
family, the spouse, their children, their parents,
Amal K. Kurban, MD, Professor of Dermatology,
and any siblings who live in the area eventuBoston University School of Medicine, and
ally become your patients too.” Since 2002,
Fred D. Malkinson, MD, DMD, Chairman Emeritus,
Dr. Turner has been named one of North
Department of Dermatology, Rush-PresbyterianCarolina’s Best Doctors in an annual survey
St. Luke’s Medical Center, Chicago, as Lifetime
compiled for a statewide publication.
Career Educators. Coverage of this award and
Dr. Turner’s commitment to patient care
details of their outstanding careers, which have
has motivated him to be involved in wider
been dedicated to educating residents and
health care issues. In 1983, he chaired a
fellows, will appear in the Spring 2006 issue.
steering committee to explore the possibility
of an HMO in the Greensboro region and
www.dermatologyfoundation.org
17
DF Welcomes New Multi-Year
Corporate Commitments
Partners in Ensuring Excellence for All of Dermatology
Two of the Dermatology Foundation’s corporate partners—
Allergan Dermatology and Abbott—
have stepped up to the level of Gold Benefactor ($100,000)
with new multi-year commitments. These investments will
support the continuation of the DF’s successful mission to
provide the specialty with a stronger scientific base and
emerging leaders in research and teaching who guarantee
quality patient care, and a strong future for medical and
surgical dermatology. Their increased giving reflects solid
confidence in the Foundation’s ability to transform its
mission into reality. Their commitment to consecutive
years of generosity supports the DF’s own emphasis on
multi-year funding of recipients as the most effective way
to ensure their career development.
co-stimulatory molecules—to instruct the
adaptive immune response to induce Tand B-cell responses. In the context of the
TLR2 system that Modlin has come to
know, he determined that the immediate
response appears to be handled by
macrophages via their intake and phagocytosis of antigens. The instructive function is
realized by the dendritic cell through its
ability to present antigens to the adaptive
immune system.
Modlin was guided in these studies by
the use of gene expression data and a computational algorithm that enabled him to
make tentative assertions, then test them
out. After developing distinctive profiles of
molecular markers to identify the phagocytic vs. the antigen-presenting cell types
that would be derived from peripheral
monocytes, first he found them expressed
on distinct, nonoverlapping cell populations
in human lymphoid tissue, and then among
monocyte-derived cells already activated by
stimulated Toll receptors. Next, he used IL-15
stimulation to induce monocytes to differ-
IFN- (pg/ml)
3,000
3H
incorporation (c.p.m.)
2,500
3,000
2,000
2,500
1,500
2,000
1,000
1,500
500
1,000
0
0.01
500
0
0.01
0.1
1
10
10-kDa protein (µg/ml)
CD1b+
DC-SIGN+
After TLR2/1 activation, monocyte-derived DCs
(labeled CD1b+) were far more potent producers
of Th1 cytokines IL-12 and TNF- compared to
monocyte-derived macrophages (labeled DC-SIGN+).
(Reprinted with permission from Nat Med. 2005;
11:p.657.)
18
0.1
1
10
10-kDa protein (µg/ml)
CD1b+
DC-SIGN+
Presenting antigen to an MHC-class II-restricted
T-cell clone that recognizes a M. leprae peptide
(10-kD protein), monocyte-derived DCs (labeled
CD1b+) triggers 20–50-fold more T-cell proliferation
and 10-fold more IFN- production compared to the
monocyte-derived macrophages (labeled DC-SIGN+),
despite similar levels of MHCII on the cell surface.
(Reprinted with permission from Nat Med. 2005;
11:p.657.)
entiate into phagocytic cells with the right
molecular profile, and GM-CSF stimulation
to induce differentiation into the antigenpresenting DCs he had profiled. Monocytes
exposed simultaneously to both cytokines
differentiated into the mixed population
similar to that found after normal TLR2/1
activation. The two different monocytederived cells behaved very differently (see
graphs below). When activated by TLR2/1,
the antigen-presenting DCs produced far
higher levels of Th1 cytokines. And when
they presented antigen to an appropriate
T cell, the DCs triggered far more T cell
proliferation and IFN- production.
When Modlin used biopsied skin from
T-lep and L-lep patients to test the in vivo relevance of these differentiation pathways—
searching for the respective presence of the
two different molecular profiles—the results
were startling—and fully in line with the
patients’ immunologic and clinical differences (see photos, page 12). Cells representing each of the monocyte-derived molecular
profiles—macrophage and DC—were present
in lesions from T-lep patients, accounting
for their strong Th1 response to the bacillus.
L-lep lesions, on the other hand, contained
only cells with the macrophage-associated
molecular profile. They were devoid of DCs.
There were no dendritic antigen-presenting
cells to instruct and initiate Th1 cell activity
after the macrophages had taken the
mycobacteria into custody.
The one exception was in those L-lep
patients undergoing reversal reaction. In
these cases, both cell types were detected
and at frequencies similar to T-lep lesions.
This was consistent with their temporary
observed gain of cell-mediated immunity and
local Th1 responses. “Because M. leprae was
found to be abundant in the macrophages
populating L-lep lesions,” Modlin says,
“we infer that the innate immune system
can mediate its direct effect in these
patients, phagocytosing the bacteria into
macrophages, but then is unable to mediate
its indirect effect, inducing dendritic cells
to stimulate the adaptive T-cell response
required to kill these intracellular pathogens.”
Given the reversal reactions characterized by
a clearance of bacilli, an influx of Th1 cells,
and the appearance of dendritic cells, “the
ability of TLR activation to regulate differentiation of monocytes into dendritic cells is
likely to be a key immunologic event for
host defense,” Modlin concludes.
TLR2 and Acne Treatment
The TLRs have also initiated productive
research on acne. Modlin’s lab initially carried out a pioneering series of studies under
the direction of Jenny Kim, MD, PhD, that
Dermatology Foundation
documented the involvement of TLR2 in
this skin pathology (see 2004, Vol. 23, No. 1).
(Kim was funded by a 3-year Clinical Career
Development Award and 1-year Research
Grant from the Dermatology Foundation.)
Before this investigation, the molecular
mechanism by which Propionibacterium
acnes induces inflammation was unknown.
Then the awareness that microbial agents
trigger cytokine responses via TLRs prompted them to see if TLR2 mediates the P. acnesinduced production of inflammatory
cytokines in acne. Transfecting TLR2 into a
cell line that normally does not respond to P.
acnes endowed it with responsiveness. Mice
engineered to lack TLR2 lost the ability to
respond to this microbe. And when acne
lesions were examined, TLR2 was in the
right place—on the cell surface of
macrophages surrounding the pilosebaceous follicles. All of these macrophages
also expressed the CD14 molecule, the telltale evidence that they had been derived
from monocytes. The clear conclusion was
that P. acnes triggers inflammatory cytokine
responses in acne by its activation of TLR2.
The thought at the time was that this receptor might provide a novel treatment target
for this common skin disease.
“Because all-trans retinoic acid (ATRA)
decreases inflammation in acne, we decided to see whether it acts by regulating TLR2
expression and function,” Modlin explains.
Treating freshly isolated human monocytes
with ATRA resulted in the down-regulation
of TLR2 and its co-receptor, the CD14 molecule. Other possible TLR candidates did not
play any role. ATRA appears to achieve its
anti-inflammatory effect in acne by preventing TLR2 from triggering monocyte cytokine
release in response to P. acnes stimulation.
Modlin concludes from these observations
that “agents targeting TLR expression and
function represent a novel strategy to treat
inflammation in humans.”
Suggested Readings
Thoma-Uszynski S, Stenger S, Takeuchi
O, et al. “Induction of direct antimicrobial
activity through mammalian Toll-like
receptors.” Science. 2001;291:1544–7.
Krutzik SR, Ochoa MT, Sieling PA, et al.
“Activation and regulation of Toll-like
receptors 2 and 1 in human leprosy.” Nat
Med. 2003;9:525–32.
Krutzik SR, Tan B, Li H, et al. “TLR activation triggers the rapid differentiation of
monocytes into macrophages and dendritic cells.” Nat Med. 2005;11:653–60.
Liu PT, Krutzik SR, Kim J, et al. “Cutting
edge. All-trans retinoic acid downregulates TLR2 expression and function.”
J Immunol. 2005;174:2467–70. ■
www.dermatologyfoundation.org
Dermatology Foundation
2005 Corporate
Honor Society
Partners in Shaping Dermatology’s Future
Cornerstone Benefactor ($500,000 to $1,000,000 annually)
Astellas Pharma US, Inc.*
Platinum Benefactor ($200,000 to $499,999 annually)
Dermik Laboratories, Inc.*
Galderma Laboratories, L.P.*
Medicis, The Dermatology Company®
OrthoNeutrogena*
Gold Benefactor ($100,000 to $199,999 annually)
Abbott
Allergan Dermatology
Connetics Corporation
Novartis Pharmaceuticals Corporation
Stiefel Laboratories, Inc.*
Unilever Home & Personal Care – U.S.A.
Silver Benefactor ($50,000 to $99,999 annually)
3M Pharmaceuticals
Amgen, Inc.
Avon Products, Inc.
Coria Laboratories, Ltd.
L’Oréal Recherche
Mary Kay Inc.
Pfizer Consumer Healthcare
Valeant Pharmaceuticals International
*$1 million pledge
19
Where Are They Now?—DF Profiles Research Award Recipients
Early Springboard for Specialty Leader
Wise investments produce outstanding returns. “Where Are They Now?” chronicles the returns for
dermatology from the DF’s wise investments in talented people. This collective investment—by individual
dermatologists, industry, and specialty societies—ensures the health of our patients and our specialty.
Former DF award recipient
Amy S. Paller, MD, praises
the DF as “the major contributor to fostering research
in dermatology of all types,
and a critical springboard
for starting young dermatologists in their careers.”
She speaks from direct
Amy S. Paller, MD
experience. Each of her
awards has translated into the continued funding
and progress that have enabled her to become
an outstanding benchtop scientist, a prominent
clinical specialist in immunologic and genetic
diseases, and a noted teacher and academic
leader. Her own career path is a clear example
of the value generated by the DF’s investment
in the best and brightest.
Dr. Paller was awarded her first Dermatology
Foundation grant in 1986 when she was a new
assistant professor of dermatology and pediatrics
at Rush-Presbyterian-St. Luke’s Medical Center, for
a project involving graft-vs-host disease. With DF
funding, she pursued her new interest in disorders
involving an altered immune status and “developed
a strong clinical interest in them,” Dr. Paller says.
This evolved into substantial clinical trials work and
regular contributions to the literature.
DF
Dr. Paller’s second DF grant in 1990—for investigating the role of gangliosides in squamous cell carcinoma—“was a very early and very critical grant for
me.” Results led to several million dollars in cumulative
NIH funding and what rapidly became “the major focus
of my lab.” Her research has generated significant
progress in skin biology, plus potential therapeutic targets in skin cancers that she is currently exploring. Dr.
Paller’s 1996 grant—targeting the use of gene therapy
to treat life-threatening hemangiomas—stimulated her
continuing focus on inhibiting pathologic angiogenesis.
Beyond the laboratory, the DF’s investment in
Dr. Paller has paid significant specialty-wide dividends.
As Chief for 16 years of the Division of Dermatology
at Children’s Memorial Hospital—part of the Northwestern University system—Dr. Paller developed the
pediatric dermatology program to international renown.
In 2004 she was named Chair of Dermatology at
Northwestern’s Feinberg School of Medicine. The DF’s
successful career support now has second-generation
impact—five of Dr. Paller’s numerous postgraduate fellows have themselves won critically timed DF Awards.
DF President Dr. Bruce Wintroub underlines
the value of the DF’s investment in people like
Dr. Paller: “These people are having, and will continue to have, an enormous impact on the specialty.
They are the thought leaders who will continue the
vitality and growth of the specialty in all its diversity.”
Dermatology Focus
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WINTER 2005/6