In vivo delayed rejection of tumors and inhibition of delayed-type hypersensitivity by HT-29 human colonic adenocarcinoma cell line.
Products secreted by HT-29 human colonic adenocarcinoma cells (DMEM-HT-29) mediated strong suppressive activity of in vitro lymphoproliferative responses to several mitogens. In vivo administration of DMEM-HT-29 both inhibited the afferent limb of delayed-type hypersensitivity against the Mc FiFi2(s) syngeneic fibrosarcoma and delayed the rejection of these tumor cells by immunized animals. Transfer experiments prior or after cell fractionation did not demonstrate suppressor cells induced by DMEM-HT-29. This suggests that DMEM-HT-29 produces its effect by directly interacting with macrophage and/or T cells at the sensitization stage of the antitumor immune response.
D000230:Adenocarcinoma / Q000276:immunology*; D000818:Animals; D003110:Colonic Neoplasms / Q000276:immunology*; D006084:Graft Rejection; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007108:Immune Tolerance; D007111:Immunity, Cellular; D007116:Immunization, Passive; D008213:Lymphocyte Activation; D051381:Rats; D012513:Sarcoma, Experimental / Q000276:immunology