title: Separation of spontaneous-killing effector populations by target preference.
abstract: Three populations active in human spontaneous cytotoxicity have been identified. Two of these are E-rosette positive, and differ in their adherence to nylon wool. The third is E-rosette negative. The E-rosette positive fraction which does not adhere to nylon consistently does not lyse a breast-cancer-derived target, MDA-157. When tested simultaneously on 4 other tumour target cells lines--Raji, Chang, K562 and Molt 4--however, all three populations are cytolytic. The MDA-157 target is consistently lysed by a nylon-adherent T-cell fraction, irrespective of whether the E rosettes are formed under optimal or the limiting conditions giving only "high-affinity" T cells. The observation that a given effector fraction can lyse one target but not another, whereas other fractions are cytolytic on both, implies that different targets may differentiate effector populations differing in their lytic mechanism.
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D003601:Cytotoxicity Tests, Immunologic; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008325:Mammary Neoplasms, Experimental / Q000276:immunology; D009374:Neoplasms, Experimental / Q000276:immunology; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology