Cytotoxic immune cells with specificity for defined soluble antigens. I. Assay with antigen-coated target cells

An in vitro cytotoxic system is described, in which immune cells specific for a given soluble antigen exert a specific cytotoxic effect on target cells to which this antigen has been covalently linked. The nature of the target cell is important in this system. When antigen-coated P 815-X2 mastocytoma cells and antigen-coated chicken red blood cells were incubated for several hours in culture medium at 37 °C, the presence of membrane-bound antigen could still be demonstrated on the latter, but not on the former target cells. This might be the reason why antigen-specific target cell destruction by specific immune cells was observed only with antigen-coated chicken red blood cells as target cells. The specificity of the cytotoxic effect was controlled in each experiment in a criss-cross way by using two non cross-reacting antigens both as immunogens and for coating the target cells. Specific cytotoxicity was demonstrable with both guinea pig and mouse immune cells and with different kinds of antigens: foreign proteins, hapten-heterologous protein conjugates and hapten-autologous protein conjugates.