Regional lymph node x-radiation suppresses allograft rejection.
We studied the effect of a single dose of x-radiation given to the regional lymph nodes on allograft rejection. Our model was an A-strain tumor, transplanted to C57B1/6, DBA/2, and C57B1/6 x CBA hosts. Irradiation (1,000 rad) of the regional lymph nodes inhibited graft rejection, as judged by increased tumor growth, slower rejection, and, in the case of DBA/2 mice, by fewer regressions; irradiation of the contralateral lymph nodes did not have this effect. The mechanism of immunosuppression appeared to be B-cell independent, since immunosuppression could be induced by regional x-radiation as readily in B-cell deficient mice as in normal mice. The suppression was critically time-dependent, viz, irradiation before, or 6 or more days after, tumor graft was without significant effect. Treatment of the allogeneic host with cyclophosphamide several days before grafting, so as to reduce T-suppressor cells, attenuated the immunosuppression of regional x-radiation.
D000818:Animals; D003520:Cyclophosphamide / Q000494:pharmacology; D005260:Female; D006084:Graft Rejection / Q000187:drug effects / Q000528:radiation effects*; D008198:Lymph Nodes / Q000528:radiation effects*; D008325:Mammary Neoplasms, Experimental / Q000276:immunology / Q000503:physiopathology; D051379:Mice; D008815:Mice, Inbred Strains; D009368:Neoplasm Transplantation; D014181:Transplantation Immunology / Q000187:drug effects / Q000528:radiation effects*
D003520:Cyclophosphamide