Because half the genes from a developing fetus are inherited from the father, from the mother’s perspective, a fetus is “foreign.” How, then, does the maternal immune system tolerate the fetus? Nancy et al. found that careful regulation of cellular recruitment signals allowed for fetal tolerance in mice. Although high numbers of T cells localized to the myometrium layer of the uterine wall in pregnant mice, very few T cells were found in the decidua, the uterine tissue that encapsulates the fetus and placenta. Thus, in pregnancy, regulation of immune cell localization may allow for organ-specific immune tolerance.
P. Nancy, E. Tagliani, C.-S. Tay, P. Asp, D. E. Levy, A. Erlebacher, Chemokine gene silencing in decidual stromal cells limits T cell access to the maternal-fetal interface. Science 336, 1317–1321 (2012). [Abstract] [Full Text]