Constraints in antigen presentation severely restrict T cell recognition of the allogeneic fetus
J. Clin. Invest. Adrian Erlebacher, et al. 117:1399 doi:10.1172/JCI28214 [Go to this article.]

Figure 3
Act-mOVA expression at the maternal/fetal interface. Sections of implantation sites of Act-mOVA (A, C, E, and F) or nontransgenic concepti (B and D) stained with anti-OVA antibodies (red). C–F also show artifactually fluorescent maternal red blood cells (green) to demarcate maternal blood vessels, and DAPI-stained nuclei (blue). (A and B) E9.5 implantation sites show high OVA expression in transgenic concepti (n = 9) confined to trophoblast giant cells (arrowheads) and trophoblasts at the invasive front of the ectoplacental cone (epc; arrow) abutting the maternal decidua (dec). Scale bar: 1 mm. (C–E) Higher-power magnifications show that transgenic trophoblasts expressing high levels of OVA had not yet invaded maternal arteries by E9.5 (C and D) but were lining maternal vessels (arrows) by E10.5 (E; n = 5). Transgenic trophoblasts expressed low levels of OVA in the body of the ectoplacental cone and developing labyrinth (lab), where they also contact maternal blood (compare the purple-tinged color of these structures in C and E, reflecting a combination of OVA staining and the DAPI counterstain, with their blue color in D). Fetal rbc appear blue-tinged due to their nucleation (arrow in D); the asterisk in C marks the vestigial uterine lumen. Scale bar: 0.4 mm. (F) At E13.5, transgenic trophoblasts expressing high levels of OVA were closely associated with or lining (arrowheads) maternal arteries deeper in the decidua (n = 3). By late gestation, high OVA expression was also apparent in the spongiotrophoblast layer (data not shown). Scale bar: 0.2 mm.