NOBEL AWARDED TO 2 DOCTORS FOR IMMUNE SYSTEM RESEARCH.

Byline: Gina Kolata The New York Times

The 1996 Nobel Prize in physiology or medicine was awarded Monday to two scientists who discovered how the immune system recognizes cells that are infected with viruses.

The discovery, by Australian doctor, Peter C. Doherty, the chairman of the department of immunology at St. Jude's Medical Center in Memphis, Tenn., and Dr. Rolf M. Zinkernagel, the head of the Institute of Experimental Immunology at the University of Zurich in Switzerland, cleared a path through the murky swamp of immunology and revealed a simple, elegant explanation for events that had seemed hopelessly complicated.

The investigators discovered that white blood cells of the immune system, whose job it is to hunt and kill virus-infected cells, must recognize two signals before destroying a target. First, they must see a self-identifying tag, a molecule that tells the immune system that the infected cell is from the same individual. Second, they must recognize a fragment of the infecting virus that a stricken cell will display on its surface.

The implications are immediate, immunologists say. By understanding the fundamental nature of the immune response, scientists can study ways both to tamp down excessive activity, as occurs in autoimmune diseases like diabetes and rheumatoid arthritis, and to amplify the response, as a new way of fighting diseases like cancer.

And the discovery helps scientists to understand the body's response to viral diseases, including AIDS, since the white blood cells in question attempt to kill any cells infected with a virus.

The two scientists did their work more than 20 years ago. They and others say, however, that it took more than a decade for them to be proved correct beyond a doubt. Now, victory is sweet.

Doherty, reached at his office, said his telephone had begun ringing at 4:30 in the morning with a call from the chairman of the Nobel committee and that it had been ringing ever since. Zinkernagel had apparently also received a deluge of telephone calls. Doherty said he had been unable to reach his colleague.

Until now, Doherty said, he has lived ``a fairly ordinary life,'' working five days a week, reading mysteries for relaxation and listening to classical music. He disdained the idea of nonstop work.

``If you're going to make your living by your wits, you can't work all the time,'' he said. ``You can't work 24 hours a day, 7 days a week and still think.''

Immunologists describe Doherty as quiet and sort of crotchety, ``like Eeyore'' from the book ``Winnie the Pooh,'' said Dr. Philippa Marrack, an immunologist at the National Jewish Center for Immunology and Respiratory Medicine in Denver.

Zinkernagel, his friends say, is flashier. ``Rolf is more of an extrovert,'' said Dr. Brigitte Huber, an immunologist at Tufts University School of Medicine near Boston. ``He likes publicity.''

Immunologists say that the discovery by Doherty and Zinkernagel - like many great discoveries - sounds simple in retrospect. But, they add, Doherty's and Zinkernagel's work shook the field.

``There were a number of different people who had been snuffling around this problem, but they couldn't reach this conclusion,'' Marrack said. She explained that others had used complicated experimental systems whose results were hard to interpret.

So when Doherty and Zinkernagel announced their results, Marrack said, it ``completely clarified the field.''

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Photo

Photo: Peter C. Doherty, left, and Rolf M. Zinkernagel, sho wn in 1983, were named winners Monday of the Nobel Prize for physiology or medicine.

Associated Press