The influence of tumor immunity suppressors on the effector stage of human and animal lymphokine-activated killer cells: Dossier “cancer”

Abstract

Spleen cells of tumor-bearing mice suppressed the cytolytic activity of syngeneic LAK cells when added to the mixture of LAK cells and target cells at the beginning of the cytotoxicity test. Spleen cells of MC 14 tumor-bearing mice acquired the suppressor potential as early as 10 days after tumor transplantation; the suppressor activity in the EL 4 and X63-Ag8.653 tumor-bearing animals was first revealed at the 30th day and manifested itself up to the 120th day. The suppressor activity was expressed in a dose-dependent manner, both by unfractionated spleen cells and nylon wool-passed and plastic-adherent sub-populations. Similar results were obtained during the analysis of anti-tumor immunity suppressors in bladder cancer patients. MNC, nylon wool-passed and plastic-adherent cells of patients with stages I–II disease suppressed the cytotoxicity of autologous LAK cells in 2 6 cases; all patients [4] with III–IV stage possessed such suppressor activity. Presumably, the tumor growth induces the activity of suppressor T cells and monocytes/macrophages. The suppressor activity can interfere with the antitumor effect of autologous (syngeneic) LAK cells at the effector stage.