Cytotoxicity tests against cultured human lung cancer cells with autologous lymphocytes activated in vitro by mitomycin C-treated tumor monolayers in the presence of T-cell growth factor.

Human peripheral blood or lymph node lymphocytes, obtained from patients with a variety of lung cancer, were incubated in vitro with mitomycin C-treated tumor monolayers in the presence of T-cell growth factor. The cytotoxicity of these lymphocytes for autologous tumor cells (autologous killer activity) was assessed by a 4-hr 51Cr-release assay. Cytotoxic activity was observed in 14 out of a total of 20 cases. Lymphocytes from patients with squamous cell carcinoma, large cell carcinoma and carcinoid exhibited positive activity levels of 11.1 +/- 1.8, 16.3 and 23.9% respectively. Nine out of 13 patients with adenocarcinoma exhibited positive activity with a mean value of 8.8 +/- 6.8%. No lymphocyte activity against small cell carcinoma was observed. Natural killer (NK) activity did not always correlate with autologous killer (AK) activity. Treatment of lymphocytes with monoclonal anti-human lymphocyte antibody revealed differences in effector cell populations concerning these two activities; AK activity was abrogated only by treatment with anti-human Lyt 3 antibody and complement, whereas NK activity was abrogated by anti-human Lyt 1, 2 and 3 and partially by anti-human Ia antibody. These results indicate that AK activity is mediated exclusively by T cells, but that NK activity is mediated by several subpopulations of lymphocytes such as T cells, null cells and others.