Role of genetic differences between mother and fetuses in the development of a graft versus host reaction induced in the mother

Development of the graft versus host reaction (GVHR) was studied in female (CBA×C57BL/6)F1 mice during pregnancy, and after birth or the day before mating with syngeneic, semisyngeneic, and allogeneic males. The development and outcome of the GVHR in the female mice was shown to depend on genetic differences between the donors of transplanted lymphocytes and the fetuses and also on the time of induction of the GVHR. If lymphocytes from C57BL/6 mice were injected into (CBA×C57BL/6)F1 females after parturition or on the day before mating with males of the parental CBA line, pregnancy led to enhancement of the GVHR; if lymphocytes were injected during pregnancy, an increase in resistance to the BVHR was observed. In the case of mating with males of the contralateral parental line C57BL/6 (syngeneic with respect to the lymphocyte donors) pregnancy did not affect the development of the GVHR regardless of the time when the cells were injected.