MEDICINE: GUIDED MISSILES

By Claudia Wallis

The three-page letter was buried deep in the Aug. 7, 1975, issue of the journal Nature. It described a method of producing huge quantities of very pure, very precise antibodies, the disease-fighting guided missiles of the immune system. The technique, said Authors Cesar Milstein and Georges Koehler of the Medical Research Council Laboratory in Cambridge, England, "could be valuable for medical and industrial use," although Milstein worried about such conjecture being "immodest."

Nine years later that prediction has proved to be an enormous understatement. Monoclonal antibodies have revolutionized biomedical research and are becoming important weapons in treating and diagnosing disease. It therefore came as no surprise to the scientific community last week when Argentine-born Milstein, 57, and West German Koehler, 38, who is now at the Institute for Immunology in Basel, Switzerland, were given the 1984 Nobel Prize for Medicine. They shared the award with Niels Jerne, 72, founding director of the Basel institute and a pioneer thinker in immunology.

The achievement of Milstein and Koehler was to fuse a tumor cell with a cell that produced a specific antibody. They thus created a hybrid that not only manufactured the antibody but multiplied as rapidly as the cancer cell. The resulting culture served as a miniature factory, churning out the desired antibody. Because every cell in the culture is an identical descendant, or clone, of the original hybrid, the antibody is pure and therefore a precise instrument. Says Milstein: "It al lows you to discriminate one molecule from another." Monoclonal antibodies can home in on targets ranging from a malignant cell to a malaria parasite to a specific structure in the brain. They have already showed promise in treating transplant and cancer patients.

Jerne's contribution to immunology is more fundamental. Born in London to Danish parents, he did not earn his M.D. until age 40, but, as the Nobel Committee observed, he quickly distinguished himself as "the great theoretician in immunology." His major theories explain how the immune system develops and matures and how its component cells are regulated. A modest man, Jerne remains less impressed with his achievement than with the object of his study. "The immune system now seems more complex than when I started out," he said last week. "I am less optimistic that we will ever be able to understand it fully.'' --By Claudia Wallis.

Reported by Margaret Studer/Zurich

With reporting by Margaret Studer