Professor Tim R. Mosmann a chemist and physiologist
who is the Director of the David H. Smith Center for Vaccine Biology and Immunology at the
University of Rochester Medical Center, USA, received the 2008 Paul Ehrlich and
Ludwig Darmstaedter Prize with a total prize money of 100,000 euros for his outstanding
contribution to the field of immunology. The award was conferred by the Council of the Paul
Ehrlich Foundation, which has explained its decision as follows: "Tim Mosmann's research
work has led to the discovery of two subsets of T helper lymphocytes, the Th1 and Th2 cells,
thereby furthering our understanding of the mechanism underlying infectious diseases and
allergies."
The Th1/Th2 paradigm
The body's immune defenses are furnished by the white blood cells or lymphocytes. While the
so-called B lymphocytes synthesize antibodies, the T lymphocytes are subdivided into CD8+
T cells, which play an important role in defense responses to viral infections, and CD4+
T helper lymphocytes. The T helper lymphocytes in turn can be broken down into two groups,
the Th1 and the Th2 cells. These two subsets can be distinguished by the different messengers
they secrete. Th1 cells play a key role in the pathogenesis of autoimmune diseases, while Th2
cells are involved, for instance, in the development of allergies.
Th1 cells synthesize the messengers interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor
necrosis factor-α (TNF-α). Th2 cells produce IL-4, IL-5, IL-6, IL-10 und IL-13. In addition to
the Th1 and Th2 subsets, which were identified in 1986, a Th17 cell has now been described,
which appears to be of crucial importance in autoimmune diseases.
It is through their release of IL-4 that Th2 cells are involved in the development of allergies,
because IL-4 stimulates the synthesis of the IgE antibodies that are characteristic of allergies.
The antagonist of IL-4 formed by Th2 cells is interferon-γ, which is synthesized by Th1 cells;
this is because interferon-γ suppresses the release of IgE antibodies. Interferon γ is released
when a virus infects a cell and prevents the virus both from replicating in the infected cells
and from infecting other cells. This explains why IFN-γ is also used to treat certain viral
diseases, including hepatitis B viral infections. Moreover, IFN-γ has another important
function: It stimulates the production of Th1 cells and so shifts the balance between Th1 and
Th2 cells in favor of the Th1 cells.
According to this concept, which is called the Th1/Th2 Paradigm and which Tim Mosmann
developed in 1986 on the basis of his work on mice, allergies develop as a consequence of a
shift in the balance of Th1 and Th2 cells in favor of Th2 cells. Just which factors are involved
in this shift is currently the focus of intensive research work, although the main "players" are
known to be IFN-γ and IL-4, along with IL-10. "Through his work, Tim Mosmann has been
instrumental in furthering our understanding of how immune defenses function in infectious
diseases, autoimmune diseases such as allergies, and chronic inflammatory diseases such as
rheumatoid arthritis," said Professor Joachim Kalden, Director Emeritus of Medical Clinic 3,
Erlangen University Hospital, and member of the Council of the Paul Ehrlich Foundation, in
his tribute to Tim Mosmann's achievements. "The knowledge gained in this way has provided
a basis for the development of new treatment options."
Short biography of Tim Mosmann
Professor Tim Mosmann was born in Birkenhead, UK, on March 7, 1949, and studied
chemistry and physiology at the University of Natal, and microbiology at Rhodes University,
both in South Africa. He completed his Ph.D. at the University of British Columbia in Canada
in 1973 and then spent two years at the Sick Children's Hospital in Toronto, Canada, before
moving to the University of Glasgow, UK. In 1977, he was appointed Assistant Professor at
the University of Alberta in Edmonton, Canada, and five years later moved to the DNAX
Research Institute in Palo Alto, California, USA, where he remained until 1990. He was then
appointed Professor of Immunology and later of Immunology and Microbiology at the
University of Alberta. Since 1998 he has been Professor of Microbiology & Immunology at
the University of Rochester and Director of the David H. Smith Center for Vaccine Biology
and Immunology. Tim Mosmann is a British citizen.
Tim Mosmann holds numerous patents, is a member of various scientific societies and a
Fellow of the Royal Society of Canada, and has won prestigious scientific awards such as the
William B. Coley Award of the United States' Cancer Research Institute (1997) and the
Avery-Landsteiner Prize of the German Society of Immunology (1994). According to data
supplied by the Institute for Scientific Information, he has been among the most widely cited
scientists since 2002. He has been scientific adviser to companies such as Genzyme
Diagnostics and MedCell Biologics, Inc..