Chimerism is required for neonatal transplantation tolerance / 中华微生物学和免疫学杂志

ABSTRACT

ObjectiveTo investigate the mechanisms of neonatal transplantation tolerance,especially the role of immature immune system and chimerism in tolerance.MethodsF1 ( or GFP-F1 ) mice were bred by crossing male C57BL/6 (or GPF transgenic C57BL/6) and female BALB/c mice. Within 24 h,newborn C57BL/6 mice were inoculated with different doses of splenocytes from F1 or GFP-F1 mice,irradiated spleen cells were used as control.Six weeks later,the mice were subjected to F1 skin grafting,and mixed-lymphocyte reaction was performed to determine their tolerance.Flow analysis was used to detect chimerism.ResultsLiving F1 spleen cells could induce chimerism and neonatal transplantation tolerance,but irradiated cells not.The chimerism in long-term tolerant mice is higher than that in chronic rejected mice,with 6.48％ ±4.02％ vs 1.57％ ±0.89％,the difference is significant in statistical analysis.The degree of neonatal transplantation tolerance is determined by the dosage of donor cells,the mice induced with 3 × 107 F1 spleen cells have 80％ long-term tolerance,but the dose of0.7×107 F1 spleen cells could only prolong allografts survival.ConclusionNeonatal transplantation tolerance is dependent on chimerism,the chimerism of donor cells leads to clonal deletion of alloreactive T cells.