In a discovery that could lead to more effective vaccines and better treatments for cancer, researchers have identified a protein that enables immune system cells to retain a memory of enemies past.The protein is found in T cells, which pick up the foreign antigens of viruses or bacteria that invade the body. The T cells multiply, sending signals that foster production of B cells, which make antibodies that attack and destroy the invaders.Once the T cells have done their job, most -- but not all -- of them die away. A small number of “memory” T cells are preserved, however, ready to rally a quick response should the infectious agent return.Until now, the molecular mechanism behind that memory has been unknown. But a group led by Hilde Cheroutre, an associate member of the La Jolla Institute for Allergy and Immunology in San Diego, reports in the April 23 issue of the journal Science that the mystery memory molecule is a form of a protein called CD8.
