Characterization of Subpopulations of Human Lymphoid Cells Participating in Phytohemagglutinin and Concanavalin A-Induced Cytotoxicity

Abstract

The cells participating in phytohemagglutinin (PHA) and concanavalin A (Con A) induced cytotoxicity mediated by human lymphoid cells were studied by means of various cell fractionation methods. A considerable decrease of cytotoxicity induced by these mitogens was observed in cell suspensions depleted of T lymphocytes forming rosettes with sheep erythrocytes, by gradient centrifugation. Also, depletion of Fc-receptor-bearing lymphoid cells, either by gradient centrifugation or by fractionation on immune complex Degalan columns, led to a marked reduction of the cytotoxic response to PHA and Con A. Our data indicate that optimal cytotoxicity induced by activation with PHA or Con A requires the presence of least two populaitons of lymphoid cells, of thymus as well as non-thymus origin.