Understanding how some diseases evade our body's defense system may help explain the incomplete control of chronic viral infections by the immune system

For Keith Jerome, M.D, Ph.D., the most intriguing question about cancer is not what causes it but why our bodies fail to defend us from the disease after it strikes.

"Infection with a cold virus brings on a very noticeable immune response — congestion, nasal swelling — all of which is part of the infection-fighting process to clear the virus from the body," said Jerome, an immunologist at Fred Hutchinson Cancer Research Center. "Yet for many cancers, there are no obvious signs of an immune reaction, despite the fact that cancer cells clearly don't look normal."

Jerome first discovered that paradox as a graduate student at Duke University about 15 years ago while doing studies on breast cancer. When he extracted women's lymph — a clear fluid that carries infection-fighting cells through the body — Jerome found immune cells that reacted against a substance found on breast-cancer cells. The immune cells he identified are known as T cells, infection-fighters that destroy virus-infected and other unhealthy cells.

"It had been thought previously that the immune system couldn't see tumors," Jerome said. "So the question then turned to, 'why isn't the immune system working to recognize and kill tumors when they arise in the body?'"

Today in his own laboratory at Fred Hutchinson, Jerome's research yields insight into this and other immune-system shortcomings that cause serious human health problems. Understanding how some diseases evade our body's defense system may help explain the incomplete control of chronic viral infections by the immune system, the lack of success of current vaccination approaches to many viruses, as well as the inability of the immune system to control many tumors. The work also may help researchers who are harnessing the protective power of T cells as new therapies for cancers.