Who was actually ... Paul Ehrlich, father of immunology and chemotherapy?

We owe many of the foundations of modern medicine to him – Paul Ehrlich. The Nobel Prize winner was a friend of clear facts and had dedicated himself to research. His maxim: to pass on only the knowledge that he could prove clearly and without doubt. The focus of his work was drug research. With Salvarsan, he developed the first effective therapeutic agent against syphilis and the first systematic chemotherapeutic agent ever.

One thing can be rightly said about Paul Ehrlich – he was a passionate researcher. Born in Strehlen in 1854 as the son of a liquor manufacturer and royal lottery collector, he studied medicine in Breslau, Strasbourg, Freiburg and Leipzig. His doctoral dissertation was entitled “Contributions to the Theory and Practice of Histological Staining” and even then referred to his passion. He sat up late into the night in the laboratory at the Charité, staining blood cells. The first direct detection of mycobacteria based on the acid fastness of the bacteria is due to his tireless efforts. Research in the field of dyes enabled significant contributions to the diagnosis of blood diseases. At that time, the oft-quoted phrase “Honest dyes last” became established. His curiosity also led him to perform his first liver biopsy. Despite his young age of 30 at the time, he was the only one who had the confidence to perform this procedure.

Laying of the foundation stone for immunology

In 1890, the scientist turned to immunity research, working closely with Emil von Behring. Numerous developments took place during this period. For example, the effective immunization protocols for obtaining high-titer therapeutic sera, experimentally different antibody qualities or immunoglobulin classes, and a method for quantitative antiserum standardization. While researching the action of the diphtheria antitoxin, Ehrlich discovers that the toxins’ poisonous effect on the organism does not parallel their binding capacity to the antitoxins. From these observations, the side-chain theory emerges as the first consistent concept in immunology. It provided indispensable information and an early description of the immune system. Ehrlich recognized that cells recognize pathogens and toxins by means of lateral receptors, bind them to themselves according to the lock-and-key principle and thus render them harmless.

Structure of the Paul Ehrlich Institute

In 1899 Ehrlich came to Frankfurt, where he initially headed the “Institute for Serum Research and Serum Testing”, later to become the Paul Ehrlich Institute in Langen. His greatest successes were at the “Institute for Experimental Therapy”, which later became the Georg-Speyer-Haus Chemotherapy Research Institute. In addition, he was one of the scientific pioneers of Goethe University, which was founded in 1914. The first description of mast cells, Ehrlich’s reagent, the description of “trucks” – that is, what is now called the carrier system, as that goes back to the ingenious and tireless scientist. In 1908 he was awarded the Nobel Prize for undying services to medical and biological research, namely for the determination of the value of serum preparations.

The merits of Paul Ehrlich at a glance

Discovery of mast cells in connective tissue

Staining of blood cells → basis of modern hematology

Development and value determination of diphtheria cure sera

Side chain theory → cornerstone for immunology

Cancer research and chemotherapy of infectious diseases

Development of Salvarsan, the first specifically causative chemotherapeutic agent

Introduction of batch testing → Basis for approval and testing of biomedical medicinal products

The search for the magic bullet

However, the main goal of his extensive research was something else entirely. He wanted to find a “magic bullet” that was toxic only to diseased cells but not to healthy ones. Moreover, it should be specific, present everywhere in the body, but active only where it is needed. After countless series of experiments with various pharmaceuticals, this became Salvarsan, the first effective therapeutic agent against syphilis and the first systematically developed chemotherapeutic agent ever. On August 20, 1915, Paul Ehrlich died in Bad Homburg vor der Höhe after a serious illness at the age of 61.