| Abstract: | Nude mice bearing allotype Ighb on a BALB/c genetic background (= CB nu/nu) are nonresponders to alpha (1----3)dextran (Dex), in contrast to BALB/c or BALB/c nu/nu. Although CB nu/nu mice accept transplants of congenic BALB/c, or BALB nu/nu lymphocytes, as shown by the expression of donor allotype Igha, they are not permissive for a primary anti-Dex response by the grafted cells. BALB/c or BALB nu/nu cells, however, give a strong anti-Dex response when grafted onto irradiated CB nu/nu or CB 23 (Ighb) euthymic mice. A thymus-independent, radiation-sensitive suppressor cell population is postulated, which specifically hinders the anti-Dex response, and which is exhibited by strains bearing that portion of chromosome 12 which codes for CH allotype Ighb, not containing the germ-line anti-Dex V/D genes. The suppressive action of Ighb lymphocytes could be demonstrated directly in staggered co-transfer experiments. |
