title: Enumeration and characterization of human killer and natural killer cells by a modified single-cell assay.
abstract: Human natural killer (NK) and killer (K) cells were assayed in a modified single-cell cytotoxicity assay using poly-L-lysine-coated cover slips. When human Chang liver cells were used as targets, 20% of the lymphocytes formed conjugates and 2% were active NK cells. When anti-Chang antibodies were present, the proportion of target-binding cells (TBC) increased to 30% and that of the cytotoxic effector cells (comprising NK + K) to 6%. With the mouse mastocytoma cells (P815), which are not susceptible to NK, similar proportions of lymphocytes formed conjugates, and 6-9% were active as K cells. By an in situ rosetting assay a significant fraction of the TBC and cytotoxic effector cells bound either C3b or C3bi in both systems, with a certain predominance of C3bi-binding cells among the K cells. However, by indirect immunofluorescence, significantly more OKT3+ cells than OKM1+ cells were TBC or cytotoxic in the Chang cell system, whereas the OKT3+/OKM1+ ratios for both TBC and cytotoxic cells were 1:1 in the mouse mastocytoma system. The results indicate that TBC, NK and K cells are heterogeneous with respect to surface marker expression and that effector cells of different phenotypes predominate in different target systems.
mesh_terms: D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity; D003176:Complement C3 / Q000378:metabolism; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods*; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology*; D011817:Rabbits / Q000276:immunology; D011951:Receptors, Complement / Q000032:analysis; D011971:Receptors, Immunologic / Q000032:analysis*
chemical_list: D003176:Complement C3; D011951:Receptors, Complement; D011971:Receptors, Immunologic