A Comparison of in Vitro Cell-mediated Reactivity against Syngeneic Tumor Cells by Various Lymphoid Cell Populations from Bacillus Calmette-Guérin-Tumor-cured, Tumor-sensitized, Tumor-bearing, and Normal Inbred Guinea Pigs

The cell-mediated reactivity (CMR) in vitro of normal, line 10 hepatocarcinoma tumor-bearing, Bacillus Calmette-Guérin (BCG)line 10 tumor-cured, and line 1 sensitized guinea pigs against syngeneic line 10 hepatocarcinoma was measured. This study was designed to determine whether the in vitro CMR correlates with the clinical stage of disease in a guinea pig immunotherapy model. A comparison was also made between the CMR of effector cells from active regional lymph nodes, pooled distant lymph nodes and spleen non-glass-adherent mononuclear cells (lymphocytes), peritoneal exudate macrophages (PEM), and peripheral blood leukocytes. In addition, the immunological specificity of the in vitro cytotoxicity was investigated by comparing the reactivities against line 10 and the highly antigenic syngeneic line 1 hepatocarcinoma as well as normal syngeneic guinea pig embryo cells. Pooled lymphocytes and PEM from normal guinea pigs were cytotoxic to line 1 hepatocarcinoma cells but not to line 10 hepatocarcinoma cells. Pooled lymphocytes and PEM obtained from animals sensitized in vivo to line 1 tumor exhibited in vitro cytotoxicity against line 1 cells, which was comparable to that cytotoxicity obtained from normal, naive donors. Various effector cells from BCG-tumor-cured guinea pigs destroyed line 10 cells but to different degrees. In the order of their decreasing cytotoxic effect against line 10 cells, the effector cells from BCG-tumor-cured guinea pigs were: glass-adherent regional lymph node cells and PEM, followed by non-glass-adherent regional lymph node cells, peripheral blood leukocytes, and pooled spleen and lymph node lymphocytes. Effector cells obtained from animals bearing line 10 tumors were all cytotoxic in vitro against line 10 cells. There were no qualitative differences in CMR between effector cells of tumor-bearing and BCG-tumor-cured guinea pigs. Although some quantitative differences between tumor-bearing and tumor-cured guinea pigs were observed, these differences were not large enough to reliably predict the clinical status of the donor in a blind test.