Surface markers on human b and t lymphocytes. VI. Cytotoxicity against cell lines as a functional marker for lymphocyte subpopulations

Abstract

The spontaneous lymphocyte-mediated cytotoxicity (SLMC) of cells from normal donors against 19 different established cell lines was analysed. All normal lymphocytes were cytotoxic in all combinations tested in a 17 h ⁵¹Cr release assay. SLMC was found to be mediated by a minor subpopulation of lymphocytes with Fc/C3 receptors. Noncytotoxic SRBC binding T-lymphocytes could be induced to become cytotoxic by the addition of Con A to the incubation medium. SLMC and lectin-induced cytotoxicity were briefly characterized. It is argued that SLMC is a non-specific non-immunological reaction which must be taken into consideration when lymphocytes from cancer patients are tested against tumour-cell lines in vitro. Furthermore, SLMC and lectin-induced cytotoxicity are proposed as functional markers for Fc/C3-binding lymphocytes and SRBC binding lymphocytes respectively.