Niels K. Jerne.

Niels Kaj Jerne (pronounced "YEHR-neh") was born on December 23, 1911, in London, England. Shortly after his birth, his family moved to Denmark and later to the Netherlands, where Jerne earned his bachelor's degree at the age of sixteen. He studied physics for two years at the University of Leiden and, twelve years later, entered the University of Copenhagen to study medicine. While working for his doctorate, Jerne also held a research position at the Danish State Serum Institute. His doctoral research dealt with the strength of interaction between antigens (foreign substances such as viruses, bacteria, and toxins) and antibodies (chemicals produced by immune cells to defend against antigens). He showed that antibody binding strength increases with every exposure to antigen. As a research fellow at the California Institute of Technology (Caltech), Jerne published a landmark paper entitled "The Natural Selection Theory of Antibody Formation," in which he proposed a revolutionary theory explaining an animal's ability to produce antibodies against a virtually limitless array of antigens. This paper provided the basis for the now universally accepted clonal selection theory of Sir Frank Macfarland Burnet. From 1956 to 1962, Jerne serve as chief medical officer of the World Health Organization (WHO) and then spent four years teaching at the University of Geneva, the University of Pittsburgh, and the J. W. Goethe University. In Pittsburgh, Jerne and Albert Nordin developed the Jerne plaque assay, a now-standard method for counting antibody-producing cells. In 1966, Jerne became director of the Paul Ehrlich Institute in Frankfurt, Germany, where he stayed until 1969. He left to become the founding director of a new institute dedicated to basic research in immunology. INSET: Niels K. Jerne.