Research on antibody In the early 1890s, Paul Ehrlich started to work with
Emil Behring, professor of medicine at the
University of Marburg. Behring had been investigating antibacterial agents and discovered a
diphtheria antitoxin (that is,
antibodies that target a biological
toxin produced by the diphtheria bacteria
Corynebacterium diphtheriae). (For that discovery, Bering was the first recipient of the
Nobel Prize in Physiology or Medicine in 1901. Ehrlich was also nominated for that year.) From Behring's work, Ehrlich understood that antibodies produced in the blood could attack invading pathogens without any harmful effect on the body. He speculated that these antibodies act as bullets fired from a gun to target specific microbes. But after further research, he realised that antibodies sometimes failed to kill microbes. This led him to abandon his first concept of the magic bullet.
Research on therapeutic properties of dyes Ehrlich joined the Institute of Experimental Therapy (
Institut für experimentelle Therapie) at
Frankfurt am Main, Germany, in 1899, becoming the director of its research institute the Georg–Speyer Haus in 1906. Here his research focused on testing arsenical dyes for killing microbes. Arsenic was an infamous poison, and his attempt was criticised. He was publicly lampooned as an imaginary "Dr Phantasus". His institute was convenient as it was adjacent to a dye factory. He began testing a number of compounds against different microbes. It was during his research that he coined the terms "
chemotherapy" and "magic bullet". Although he used the German word
zauberkugel in his earlier writings, the first time he introduced the English term "magic bullet" was at a Harben Lecture in London in 1908. By 1901, with the help of Japanese microbiologist
Kiyoshi Shiga, Ehrlich experimented with hundreds of dyes on mice infected with
trypanosome, a protozoan parasite that causes
sleeping sickness. In 1904 they successfully prepared a red
azo dye they called Trypan Red for the treatment of sleeping sickness. ==Discovery of the first magic bullet – Salvarsan==