Karl Landsteiner

Karl Landsteiner was born in Austria in 1868 and trained as a physician and immunologist. In 1901 he distinguished the main blood groups, developing the modern classification system by identifying agglutinins in blood — the discovery that made safe transfusion possible. In 1909, working with Constantin Levaditi and Erwin Popper, he discovered the polio virus. At 55 he emigrated to New York for professional opportunities, joining the Rockefeller Institute in 1923. In 1937, with Alexander S. Wiener, he identified the Rhesus factor, giving physicians another critical safeguard. He received the No…