Lysis of human solid tumors by autologous cells sensitized in vitro to alloantigens

Human lymphocytes sensitized in vitro to allogeneic single-donor cells as well as to pools of allogeneic donor cells were evaluated for their cytotoxic potential against autologous fresh solid tumor cells, autologous tissue-cultured tumor and fibroblasts, fresh peripheral blood lymphoid cells (PBL), and Con A blasts of PBL. Using 4-hr ⁵¹Cr release assays, pool-sensitized effector cells lysed autologous tissue-cultured tumor and fibroblast targets in 4 of 4 experiments. Similarly, in 2 of 2 experiments with single-donor allosensitized effectors, autologous tissue-cultured tumor was lysed. No lysis of fresh PBL was seen. Significant lysis of fresh autologous tumor target cells was seen in 10 of 12 experiments. Fresh tumor cells, PBL, and Con A blasts appeared equally lysable, since they were equally lysed by effector cells specifically sensitized to alloantigens present on these cells. Cold target inhibition studies demonstrated that cultured tumor and fibroblasts but not PBL shared the determinants recognized by pool-sensitized cells.