Modulation of cellular anti-tumour responses by tumour-specific T suppressor lymphocytes.
Tumour-specific Ts cells, induced by a protocol which simulates early stages of tumourigenesis in BALB/c mice by the syngeneic plasmacytoma ADJ-PC-5, suppress the generation of specific cytotoxic T lymphocytes (CTL) in a primary in vitro mixed lymphocyte tumour culture (MLTC) of BALB/c spleen cells against ADJ-PC-5. The influence of these Ts cells on the generation of non-specific killer cell activity has now been analysed. The data show that non-specific killer cells generated during in vitro MLTC lyse both ADJ-PC-5 and YAC-1 cells. They are different from tumour-specific CTL as shown by cold target inhibition experiments and on the basis of their different phenotype. The generation of non-specific killer activity during MLTC can be completely suppressed by ADJ-PC-5 specific Ts cells. Activation of non-specific killer cells by recombinant interleukin-2 (r IL2) alone is not influenced by these Ts cells. The in vitro data are best explained by assuming that the target for suppression are ADJ-PC-5 specific T helper cells. Their inactivation will result in depletion of IL2 in the culture, which is required to activate non-specific killer cells. Prevention of activation of specific and non-specific killer cells in vitro by activated tumour-specific Ts cells in the presence of the tumour, suggests that similar mechanisms might operate in vivo and that inactivation of tumour-specific T helper cells might be of central relevance.
Haubeck
H D
HD
Institut für Immunologie, Universität Münster, FRG.
Stutenkemper
R
R
Kölsch
E
E
D000818:Animals; D005260:Female; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000276:immunology*; D010954:Plasmacytoma / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014407:Tumor Cells, Cultured / Q000276:immunology
D007376:Interleukin-2