Which scientist developed the first diphtheria antitoxin?

The scientist who developed the first diphtheria antitoxin was Emil von Behring. Working at Robert Koch’s institute in Berlin, Behring and Shibasaburo Kitasato showed in 1890 that animals exposed to diphtheria toxin could produce protective substances in their blood. Serum from immunized animals could then protect or treat other animals.

The antitoxin did not directly kill Corynebacterium diphtheriae. Instead, its antibodies neutralized the powerful toxin released by the bacterium. Early attempts to use the treatment in humans were unsuccessful, but production and dosage were improved. By 1894, horse-derived diphtheria antitoxin was being used successfully in patients. Paul Ehrlich helped standardize its strength, making treatment more reliable.

Behring’s work launched serum therapy and transformed the treatment of a disease that was especially deadly to children. In 1901 he received the first Nobel Prize in Physiology or Medicine for his work on serum therapy, particularly its application to diphtheria. Kitasato was a crucial collaborator, so the discovery is often described as a joint achievement even though the Nobel Prize went to Behring alone.