Wayne M. Yokoyama
Washington University in St. Louis
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Primary Section: 43, Immunology and Inflammation Secondary Section: 42, Medical Physiology and Metabolism Membership Type:
Member
(elected 2007)
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Research Interests
I have had a long-standing interest in immunology, the study of the body's defense against infections and tumors. Our focus has been on a subpopulation of leukocytes called natural killer (NK) cells. Although NK cells were initially thought to display "non-specific" killing against tumors, our studies indicated that NK cells display receptors with specificity for ligands expressed on their cellular targets. These NK cell receptors are germline-encoded by a complex of clustered genes, unlike closely related T cells that derive their receptors by gene rearrangements. Ironically, the first identified NK cell receptors inhibit NK cell activation and specifically recognize major histocompatibility complex (MHC) class I molecules that otherwise can activate T cells. Recently, we showed that the MHC-specific NK cell receptors have another function presumably during NK cell development; they can engage self-MHC molecules and endow an individual NK cell with the capacity to be stimulated through its activation receptors. Other studies showed that NK cell activation receptors can specifically recognize virus-infected cells, providing the genetic basis for the vital role of NK cells during the earliest phases of immune responses. Thus, our studies have led to an appreciation of NK cell specificity in host defense against infections and tumors.
