Behring and Kitasato's antitoxins

Diphtheria filled children's wards, and its victims died of suffocation, paralysis or heart failure. Émile Roux and Alexandre Yersin at the Pasteur Institute in Paris found that diphtheria cultures stayed toxic after the bacteria were filtered out, so the damage came from a toxin. Emil von Behring, an army doctor, had been ordered back to Berlin in 1888 to work as an assistant under Robert Koch.

Behring began by asking whether an infected animal could be disinfected from within, and he injected animals with bacterial material treated with various disinfectants, above all diphtheria and tetanus bacilli. Shibasaburo Kitasato, a Japanese bacteriologist, had studied the tetanus bacillus; one history credits him with identifying it in 1889. In 1890 the two reported that graded doses of sterilized cultures made animals produce substances in their blood that neutralized the bacterial toxins. They called them antitoxins, and they showed that serum from one animal could immunize another and cure an animal already showing diphtheria.

Other workers soon confirmed the findings. According to Hektoen International, the first child treated with diphtheria antitoxin, a seriously ill girl at a Berlin clinic at Christmas 1891, recovered, and serum treatment then spread through Europe and the United States.

In 1901 Behring received the Nobel Prize in Physiology or Medicine. He went on to work with mixtures of toxin and antitoxin: with F. Wernicke in 1898 he found that neutralized toxin could immunize animals against diphtheria, and in 1913 he announced such a mixture for people, later refined into the methods of immunization that largely banished the disease. In 1914 he founded the Behringwerke in Marburg to make sera and vaccines.