Inhibition of T cell proliferation by macrophage tryptophan catabolism

HLA-G transgenic mice

We have generated a number of transgenic mice using DNA segments derived from the HLA-G gene. Using these mice we have examined the pattern of expression dictated by HLA-G promoter elements in mice and shown that HLA-G functions both as a restriction element and a transplantation antigen recognized by murine T cells. In addition, we have shown that trophoblast cells expressing H-2Kb under the control of HLA-G promoter elements affect maternal T cell phenotype and responsiveness during pregnancy. Using these same HLA-G/H-2Kb transgenic mice we have shown that trophoblast cells, expressing an inducible enzyme that degrades tryptophan, protects allogeneic conceptus expressing paternally-inherited transgenes from attack by maternal T cells that leads to fetal rejection.