CELL-MEDIATED IMMUNITY TO H-2 ANTIGENS

Abstract

Cell-mediated immune reactivity against murine histocompatibility antigens was compared by using the microcytotoxicity assay (MCA) and the 51Cr release assay (CRA). In both assay systems, T [thymus-derived] cell-mediated reactivity was demonstrated. In the CRA, only T lymphocytes were detectable, which were cytotoxic. In the MCA, reactivity of nonlytic secondary T cells (NLST) was detected. NLST acquired their MCA-reactivity within the first 24 h of the 48 h test period of the MCA. MCA reactivity is probably a product of 2 different processes, namely, antigen-specific restimulation of immune T cells and shedding of cytotoxicity inhibiting factors.