César Milstein October 8, 1927– March 24, 2002

or more of radioactive myeloma cells to concentrate them into a few milliliters. This would invariably result in a trail of radioactivity across the corridor from the cold room to the hot room where these procedures were Cé sar Milstein died in the early hours of 24 th March 2002. carried out. These studies, plus immunoglobulin protein He had a long history of cardiovascular illness, to which synthesis work, showed that the precursor of the light he finally succumbed. We will always remember his en-chain was made with a hydrophobic leader sequence thusiasm for science and his kind attention to the prob-for specifying transfer to the endoplasmic reticulum. lems of others. His most famous contribution to biology Cé sar always tackled scientific problems from many was the invention of monoclonal antibodies (also called angles, and he was not content with straight molecular hybridomas, but that was a term he never really liked) biology. Rather, he was also keen to see if cells could for which he was awarded the Nobel Prize for Physiology discriminate immunoglobulin heavy and light chains of or Medicine in 1984, along with George Kohler, who differing origins, and he set about fusing rat and mouse worked with Cé sar on the key experiments that led to immunoglobulin-producing cell lines. With Dick Cotton, their landmark paper, published in Nature in 1975. many experiments were done to show how heavy and Cé sar was born in Argentina in 1927 and developed light chains associate. Later, George Kohler joined Cé-an early interest in immunology through family connec-sar's group as a post-doc. Together they hatched the tions; this was an enthusiasm that was to last throughout idea of fusing spleen cells with mouse myeloma tissue his sparkling career. After being a none-too-keen culture cells to immortalize the spleen immunoglobulin schoolboy, he went to Buenos Aires University to study and, of course, the stroke of brilliance here was that chemistry. He obtained a BSc and then a Ph.D. studying preimmunizing mice with antigen allowed predefined aldehyde dehydrogenase in the laboratory of Andres Stoppani. He later traveled to Cambridge, England, and worked in the University Department of Biochemistry with Malcolm Dixon, where he obtained a second Ph.D. was a wonderful opportunity for him as the MRC support allowed his research to blossom by setting few constraints on what he could do. How well-suited this environment must have been for the young Milstein! …