In Vitro Induction and Expression of T-Cell Immunity to Tumor-Associated Antigens

Abstract

The development of in vitro assays of cell-mediated cytotoxicity has provided a means both of quantitating cell-mediated immunity (CMI) induced in vivo, and also of identifying thecytotoxic effector cells (CL) involved. Studies with the⁵¹ Cr release assay have clearly shown that a specific subpopulation of T lymphocytes (termed T_c-cytotoxic T lymphocytes) are responsible for mediating cytotoxicity in vitro, when cell preparations from animals undergoing allograft rejection or graft-versus-host reactions are assayed in vitro (Cerottini et al, 1970; Miller et al, 1971 ; Cerottini and Brunner, 1974). The T_c subpopu-lation has been further characterized in terms of cell-surface markers and is a distinct T-cell lineage of phenotype Ly-1 negative, Ly-2 positive, Ly-3 positive (Cantor and Boyse, 1976). Since cytotoxic T cells are, however, to be found in both Fc receptor-positive and-negative lymphocyte groups, some heterogeneity may still exist within the T_C population (Stout et al., 1976). The results of in vitro assays of lymphoid cells from animals immunized with tumor cells have, however, been much less clear-cut, and the number of different effector cell types and the mechanisms of cytotoxicity have proliferated rapidly since the introduction of techniques for identifying different subpopulations of lymphocytes and mononuclear cells (Table I).