Studies on natural killer (NK) cells. II. Serologic evidence for heterogeneity of murine NK cells.

NK cells are divided into 2 subclasses on the basis of cell surface antigens: NKA cells, which preferentially lyse lymphoma cells and which are readily destroyed by treatment with anti-H-2, rabbit anti-mouse, or anti-NK specific antibodies in the presence of C; and NKB cells, which preferentially lyse nonlymphoma tumor cells and which are resistant to anti-NK specific antibodies, partially sensitive to anti-H-2 specific antibodies, and only fully sensitive to rabbit anti-mouse serum and C. Thus, suspensions of spleen cells that were treated with anti-NK-1.2 antibodies and C lost virtually all lytic activity for 6 lymphoma cell lines, whereas lytic activity for 2 nonlymphoma cell lines remained largely intact. It must be noted, however, that unlike NK-1.2 expression, target cell preference is not an absolute indicator of NK cell subclass. Cytotoxic T cells were readily distinguished from NKA and NKB cells on the basis of their sensitivity to monoclonal anti-Thy-1.2 antibodies and resistance to anti-NK-1.2 antiserum and C.