Interaction of lymphocytes from allophenic mice with spleen colony-forming units of the parental genotype

Self-tolerance in allophenic mice has been studied. CB6 and CSM chimeras were obtained by aggregation of mouse BALB/c(C), C57BL/6 (B6), and B10.SM (SM) embyros. Chimerism was determined according to coat mosaicism, using electrophoresis of allozyme variants at the Gpi-1 locus in the population of peripheral blood erythrocytes and a cytotoxicity test in the populations of blood nucleated cells and lymph node lymphocytes. An age-dependent increase in the per cent content of BALB/c erythrocytes was observed in both chimera types. The immunological status of chimeras was assessed by T-cell interactions with spleen colony forming cells (SFU-S) able to form colonies in the recipients spleens. Lymph node lymphocytes of the chimeras together with bone marrow cells of the parental genotype were transplanted to lethally irradiated F₁ hybrids. Chimera T-lymphocytes did not inactivate CFU-S of the parental genotype and colonies formed in the spleens of F₁ hybrids. The absence of splenic colonies in (C x B6) F₁ hybrids, to whom bone marrow cells of B6 had been transplanted (alone or in combination with chimera lymphocytes), was due to the reaction of host natural killer (NK) cells. The results obtained testify to the permanent immunological tolerance of lymphocytes from allophenic mice to cell antigens of both parental genotypes. The chimeric drift in the erythrocyte population is not coupled to disturbances in self-tolerance of chimeric mice.