Suppression of the leukocyte adherence inhibition response to murine-sarcoma-virus-induced tumors by tumor-associated suppressor cells.
The tumor-specific leukocyte adherence inhibition (LAI) response of lymphoid cells from C57B1/6 mice sensitized to a murine-sarcoma-virus (MuSV)-induced tumor was inhibited by adherent phagocytic spleen cells from mice with progressively growing RBL-5 tumors. Both the direct LAI response and the formation of the mediator of LAI were sensitive to the suppressive activity of the progressor spleen macrophages. Suppression of LAI was not restricted by H-2 differences between the sensitized lymphocytes and progressor macrophages. Suppression was also nonspecific since the antibody plaque-forming cell response of normal lymphocytes to triphenylated hemocyanin was lowered by the addition of progressor spleen macrophages. Removal of adherent suppressor macrophages during the late stages of tumor growth revealed greatly elevated LAI reactivity not detectable in an unfractionated population.
D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D005260:Female; D007957:Leukocyte Adherence Inhibition Test; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D009053:Sarcoma Viruses, Murine / Q000276:immunology*; D012513:Sarcoma, Experimental / Q000276:immunology* / Q000382:microbiology; D013154:Spleen / Q000166:cytology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*