Karl Landsteiner (1868-1943), the Austrian-born American immunologist and Nobel Prize winner, discovered blood groups and helped establish the science of immunochemistry.

Karl Landsteiner was born in Vienna on June 14, 1868. In 1891 he was awarded a medical degree by the University of Vienna. For the following 5 years he studied physiological chemistry in laboratories in Germany and Switzerland. In 1898 he moved to the Pathological Anatomical Institute in Vienna, where he carried on work that led to the discovery of blood groups.

It was known that blood transfusion often resulted in dangerous or fatal clumping of the red blood corpuscles. After a series of tests performed in his laboratory, Landsteiner postulated the existence in the corpuscles of agglutinogens (antigens) called A and B and in blood serum of agglutinins (antibodies) called anti-a and anti-b. Reaction to transfused blood (clumping) depended on whether the agglutinogens A, or B, or A and B, or...