Changes of immunological patterns of human cancer cells treated in vitro with a triazene compound

Previous experimental evidence indicates that immunogenicity of mouse tumor cells can be increased by treatment with dacarbazine and other triazene compounds. The present studies have been conducted on the human cell lines H125 (lung cancer), 1246 (melanoma), X3 (EBV-immortalized B cells) subjected to in vitro treatment with 4 (3-methyl-1-triazeno) benzoic acid potassium salt (MTBA). Untreated or drug-treated sublines were tested for susceptibility to allogeneic NK effector cells, either non-stimulated or pretreated with beta-Interferon. In the case of X3 cell line and its MTBA-treated subline the expression of the EBV-associated antigens and the capability of eliciting autologous cytotoxic T lymphocytes (CTL) were also investigated. The results suggest that a modification of membrane antigenic pattern could be induced by MTBA treatment in terms of changes of cell susceptibility to cell-mediated lysis, expression of EBV-related antigens and capability to elicit autologous CTL.