Functional fractionation of human cytotoxic cells using differences in their cation requirements.

Abstract

DEMONSTRATION of anti-tumour immunity in man is often impaired by the variable level of cytoxicity of normal control cell populations. Using physical fractionation techniques, attempts have been made to remove selectively the cells which are responsible for this ‘variable background’ effect1,2, and to improve characterisation of cytotoxic cell populations. We report here that several types of human cell-mediated cytolysis have different extracellular cation requirements either for Ca2+, for Mg2+, for both, or for neither. These findings suggest the existence of differences in the mechanism(s) of lysis, and lead us to propose an alternative, functional approach to the fractionation of cytotoxic cells.