Dr. Kumar has devoted his career to research in the cellular and molecular biology of natural killer (NK) cells. His laboratory is interested in the cellular and molecular biology of murine natural killer (NK) cells. These cells are believed to act as the first line of defense against tumors and viral infections. In addition they secrete a variety of cytokines including 1FN-δ and GM-CSF that can influence the inflammatory response. Two aspects of NK cell biology are of particular interest to us: the development of NK cells from multipotent progenitor cells, and the identification of NK cell receptors and their ligands. NK cells play a prominent role in β-cell loss in type 1 diabetes.