- For the American butterfly and overpopulation specialist, see Paul R. Ehrlich.
Paul Ehrlich (March 14, 1854–August 20, 1915) was a German scientist who won the 1908 Nobel Prize in Physiology or Medicine. He is noted for his work in hematology, immunology, and chemotherapy. Ehrlich predicted autoimmunity and called it "horror autotoxicus". He coined the term "chemotherapy". The idea of a "magic bullet" is also his.
Paul Ehrlich was born on 14 March 1854 in Strehlen (Silesia). Already as a pupil and student of medicine he was interested in colouring microscopic tissue substances.
In his dissertation at the Leipzig university he picked up the topic again ("Beiträge zur Theorie und Praxis der histologischen Färbung").
After his clinical education and habilitation ("Das Sauerstoffbedürfnis des Organismus") at the Charité in Berlin in 1887 he received a call from Robert Koch to join the Institute for Infection Diseases in Berlin (1891).
Paul Ehrlich overcame the tuberculosis disease, with which he was infected in Egypt. Thereafter he worked with his friend Emil Adolf Behring to contribute to the development of the diphtheria serum.
These works were inspirations to his famous side-chain theory (Seitenkettentheorie) from 1897. This theory explained the effects of serum and allowed to measure the amount of antigen. In 1896 Ehrlich became the director of the newly founded Royal Institute of Serum Research and Examination (Königlichen Instituts für Serumforschung und Serumprüfung) in Steglitz (Berlin). In 1899 the institute was moved to Frankfurt (Main) and extended into the Institute of experimental therapy (Institut für experimentelle Therapie). Here Ehrlich researched chemotherapy and infection diseases. In 1904 Ehrlich became honorary professor of the University of Göttingen.
Paul Ehrlich received the Nobel Price for Medicine together with Ilja Iljitsch Metschnikow in 1908. In 1909 he and his student Sahachiro Hata developed Salvarsan, a medicine against syphilis and other epidemic diseases .
Paul Ehrlich died on 20 August 1915 in Bad Homburg.
His life is depicted in the movie The Magic Bullet, which focused on Salvarsan® (arsphenamine, "compound 606"), his cure for syphilis. His work raised the existence of the blood-brain barrier.
The "magic bullet" concept comes from the experience of 19th century German chemists with selectively staining tissues for histological examination, and in particular, selectively staining bacteria (Ehrlich was an exceptionally gifted histological chemist, and invented the precursor technique to Gram staining bacteria). Ehrlich figured that if a compound could be made that selectively targeted a disease causing organism, then a toxin for that organism could be delivered along with the agent of selectivity. Hence, a "magic bullet" would be created that killed only the organism targeted.
A problem with the use of the magic bullet concept as it emerged from its histological roots is that people confused the dye with the agent of tissue selectivity and antibiotic activity. Prontosil , a sulfonamide, whose active component is sulfanilamide, is a classic example of the fact that color is not essential to antibiotic activity.
The concept of a "magic bullet" was fully realized with the invention of monoclonal antibodies.