The suppressive effect of immunization on the proliferative responses of rat T cells in vitro. II. Abrogation of antigen-induced suppression by selective cytotoxic agents.
Rats given large i.v. doses of ovalbumin or sheep erythrocytes manifest suppressed spleen cell responses (3H-thymidine incorporation) to PHA within hours. Removal of glass wool-adherent cells totally restores responsiveness to that of normal nonadherent spleen cell cultures. Carrageenan, selectively toxic for macrophages, partially restores responses of antigen-suppressed spleen cells in culture, suggesting a supportive role for macrophages in the suppression phenomenon. Treatment of donors with low doses of cyclophosphamide (20 to 50 mg/kg) at the time of antigen injection abrogates the ability of their spleen cells to suppress the responses of normal cells to PHA. The low dose of cyclophosphamide required indicates a target other than the B cell or macrophage and suggests the possibility that cyclophosphamide eliminates the suppressor T cell component of the macrophage-T cell complex.
D000818:Animals; D000941:Antigens / Q000008:administration & dosage; D002351:Carrageenan / Q000494:pharmacology*; D003520:Cyclophosphamide / Q000494:pharmacology*; D004912:Erythrocytes / Q000276:immunology; D007114:Immunization; D007165:Immunosuppression Therapy; D066298:In Vitro Techniques; D007275:Injections, Intravenous; D008213:Lymphocyte Activation; D008297:Male; D010047:Ovalbumin / Q000008:administration & dosage; D051381:Rats; D011917:Rats, Inbred Lew; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology*
D000941:Antigens; D003520:Cyclophosphamide; D002351:Carrageenan; D010047:Ovalbumin