| any of several types of lymphocyte or leukocyte capable of destroying cells that have acquired foreign characteristics, as a tumor cell or virus-infected cell. |
| killer cell n. Any of various large differentiated T cells that recognize and lyse target cells bearing a specific foreign antigen, usually by infection with a virus, and that also function in defense against cancer cells. Also called cytotoxic T cell, killer T cell. |
killer cell kill·er cell (kĭl'ər)
n.
A large differentiated T cell that attacks and lyses target cells bearing specific antigens. Also called cytotoxic T cell, killer T cell, null cell.