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Michael Heidelberger Added to Profiles in Science

The National Library of Medicine is pleased to announce that its Profiles in Science Web site has been further enriched by an extensive selection from the papers of one of the fathers of modern immunology, Michael Heidelberger. With this addition the number of prominent researchers and public health officials whose personal and professional records are presented on Profiles has grown to nineteen. The site is at

Michael Heidelberger (1888--1991) was the founder of immunochemistry, the branch of biochemistry that examines the immune system of animals on a molecular level. His seminal discovery with Oswald T. Avery (also on Profiles in Science) in 1923 that powerful disease-causing antigens of pneumococcus bacteria are polysaccharides opened up an expansive new area in the study of microorganisms, and brought about a new understanding of infectious diseases, their treatment, and their prevention. "Heidelberger redefined the field of immunology and founded it on the precise analytical basis of biochemistry," says Donald A.B. Lindberg, M.D., Director of the National Library of Medicine.

During his long scientific career--he lived to be 103--Heidelberger devoted himself single-mindedly to exploring the role of polysaccharides in immune phenomena. Using polysaccharide antigens as reagents, he determined, for the first time, the exact weight and many structural details of antigens and the antibodies that fight them. During the 1930s he showed that antibodies are proteins, until then a matter of scientific dispute, and that antibodies and antigens are multivalent, meaning that they have two or (in the case of antigens) more binding sites. He drew on these findings to develop a vaccine against pneumonia whose effectiveness was first proven in World War II soldiers, and which in modified form remains in use today.

Michael Heidelberger was born in 1888 in New York City, and decided at age eight that he wanted to be a chemist, which he himself later judged no more than a "pigheaded idea." He received all of his academic degrees from Columbia University, culminating with a Ph.D. in organic chemistry in 1911. During his years of schooling he also developed his second passion, classical music. He became a clarinetist of professional caliber, and took his instrument with him wherever he went to join in chamber music performances at conferences or the homes of friends.

After a year in the laboratory of the 1915 Nobel Laureate Richard Willstätter in Zürich, Heidelberger joined the Rockefeller Institute of Medical Research (today Rockefeller University), where he developed important chemotherapeutic drugs, including tryparsamide, an effective agent against African sleeping sickness. In 1923, Heidelberger and his Rockefeller Institute colleague Oswald Avery reported that the substance which determined the virulence of different types of pneumococcus bacteria consisted not of proteins, as most scientists had expected, but of polysaccharides, a form of carbohydrates. Their discovery established a relationship between the chemical constitution of antigens and their mode of action in the body, long a goal of immunologists.

After fifteen years at the Rockefeller Institute and one year at Mount Sinai Hospital, Heidelberger took a position as consulting research chemist in the Department of Medicine of the College of Physicians and Surgeons at Columbia University. There he and his collaborators Forrest E. Kendall and Elvin A. Kabat formulated a quantitative theory of immune reactions, which allowed for the accurate measurement of the antibody content of vaccines made from antisera. They also were the first to isolate certain proteins, which are called complement, that regulate antibody-antigen reactions.

In 1954, Heidelberger moved to the Institute of Microbiology at Rutgers University, before becoming adjunct professor in the Department of Pathology at New York University Medical School in 1963. He published over 350 scientific articles, spread over every decade of the twentieth century. His discoveries were honored in 1953 and again in 1978 with a Lasker Award, often called America's Nobel Prize.

The online exhibition features correspondence, diary entries, draft and published articles, laboratory notebooks, and photographs from the Michael Heidelberger collection at the National Library of Medicine. Visitors to the site can view, for example, a diary of Heidelberger's grand tour of leading European research laboratories in 1924, the score for a march Heidelberger composed on the occasion of his wedding in 1916, and his humorous explanation of "My Idea of Why I Failed to Win a Nobel Prize."

Profiles in Science was launched September 1998 by the National Library of Medicine, a part of the National Institutes of Health in Bethesda, Maryland, a constituent agency of the Department of Health and Human Services.