Figure 3.

Rescue of CD40 ligation–induced pregnancy failure by exogenous progesterone. (A–H) Whole-mount uteri (A, C, E, and G) and implantation-site histology (B, D, F, and H) from mice on E8 following daily treatments on E4–7. Paraffin sections of implantation sites were stained with anti-CD45 antibodies to visualize all leukocytes (red), and counterstained with DAPI (blue). Only mice treated with FGK45 and sesame seed oil vehicle (C and D) showed abortion, leukocytic infiltration into the uterine stroma, and occasional cell debris in the uterine lumen (D, arrowhead). The CD45 staining intensity in these sections tended to be greater than that at viable implantation sites, because they do not contain the high numbers of CD45^dim uterine NK cells that are present in the decidua. Immunostaining is representative of two mice per group, encompassing a total of about 12 implantation sites in each group. Scale bar: 0.5 mm.