Michael Heidelberger, American immunologist (died 1991)

Michael Heidelberger was an American immunologist, often regarded as the father of modern immunology. He and Oswald Avery showed that the polysaccharides of pneumococcus are antigens, enabling him to show that antibodies are proteins. He spent most his early career at Columbia University and comparable time in his later years on the faculty of New York University. In 1934 and 1936 he received the Guggenheim Fellowship. In 1967 he received the National Medal of Science, and then he earned the Lasker Award for basic medical research in 1953 and again in 1978. His papers are held at the National Library of Medicine in Bethesda, Maryland.

April 29 is the 119th day of the year in the Gregorian calendar; 246 days remain until the end of the year.