B cell dependence of the congeneic barrier towards idiotype-carrying cells.

Immune cells transferred into nonirradiated animals of the same genotype face a barrier which severely affects their capacity to function in the host. We studied this phenomenon in allotype-congeneic animals. When anti-dextran immune cells of the responder strain (BALB/c-Igha) are injected into an allotype-congeneic host (BALB-Ighb) the grafted cells are suppressed to give an idiotype-positive response. This congeneic barrier of thymus-independent immune cells is lost in mice carrying an X-linked B cell defect: when idiotype-positive immune cells from responder (CBA/N X BALB/c)F1 mice are transplanted into congeneic nonresponder animals (CBA/N X BALB-Ighb)F1, female recipients are nonpermissive towards grafted cells whereas B cell-defective male littermates allow donor cells to develop an idiotype-positive anti-dextran response. These results show that the congeneic barrier towards dextran-immune cells is related to the maturation stage of B cells in the recipient. Since B cell-defective (CBA/N X BALB/c)F1 animals do not display an anti-idiotypic response in contrast to intact littermates and because CB16-KN mice are nonpermissive towards CB8-K lymphocytes, differing in VH genes only, we suggest that the "isogeneic barrier" depends on a mechanism recognizing VH structures.