[The mechanism of the recipient maternal-fetal immuno-tolerance induced by the transferred paternal antigen-tolerant T cells].

To study the effect of adoptive transfer of paternal antigen-tolerant T cells on re- cipient reactive T cells, CBA/JxDBA/2 mating was recruited as an abortion-prone model, and CBA/JxBALB/c mating as a successful pregnancy model. The abortion-prone CBA/J females mated with DBA/2 males were injected intraperitoneally with rat anti-mouse CD80 and CD86 mAb or rat isotype IgG at day 4 after gestation (time of implantation). The purified T cells were obtained from spleen of the pregnant CBA/J mice using magnetic beads at day 9 after gestation and labeled with CFSE in vitro. The CFSE-labeled T cells were intravenously injected into other CBA/J females mated with DBA/2 males at day 4 after gestation. The proliferation of recipient splenocytes in response to DBA/2 stimulator cells was evaluated at day 9 after gestation in vitro, and the expressions of intracellular cytokines and costimulatory molecules in CFSE~(+/-)T cells were analyzed by flow cytometry. The results showed that adoptive transfer of either paternal antigen- tolerant T cells or T cells from BALB/c-mated CBA/J mice significantly suppressed the prolifera- tion of recipient splenocytes in response to DBA/2 stimulator cells and resulted in lower frequen- cy of cells positive for IL-2, IFN-γ, CD28 and higher frequency of IL-10, CTLA-4-producing cells in both CFSE~+ CD3~+ population and CFSE~- CD3~+ population compared with adoptive transfer of T cells from isotype IgG-treated CBA/J mice, whereas the frequency of IL-4-producing cells did not appear significant change. Our findings suggest that paternal antigen-tolerant T cells trans- ferred in recipient not only function as antigen-specific suppresser cells but also disable the re- cipient reactive T cells, which co-suppresses maternal rejection to the allogeneic fetus, thus result- ing in the decrease of the embryo resorption rate of the abortion-prone mice to that of the nor- mal pregnancy mice.