Expression of carbohydrate antigens in the Goat uterus during early pregnancy and on steroid-treated polarized uterine epithelial cells in vitro

Our objectives were to determine whether specific fucosylated carbohydrate antigens, associated with uterine receptivity in rodents, are expressed in pregnant caprine uterine tissues and polarized uterine luminal epithelial ( ULE) cells in culture. Immunofluorescence microscopy on frozen endometrium revealed that expression of the H-type 1 antigen, confined to epithelial ce lls, was regulated during early pregnancy. Staining was high on Day 5 and l ow on Days 11 and 13. Strong, uniform apical staining was characteristic of ULE cells between Days 15 and 19 but declined markedly by Day 25. Immunofl uorescence analysis of the apical surface of polarized ULE cells cultured i n steroid-free medium revealed weak and diffuse staining for the H-type 1 a ntigen, while progesterone (P-4) treatment resulted in the formation of agg regates of punctate staining along the apical surface. Domain-specific biot inylation of polarized ULE cells, coupled with streptavidin precipitation a nd Western blotting, revealed that six apical surface proteins (31, 33, 42, 55, 60, and 70 kDa) carry the H-type 1 antigen. Therefore, H-type 1 antige n expression is up-regulated in vivo during the periimplantation period, st imulated by P-4 on polarized ULE cells in culture, and may be a useful mark er for uterine receptivity in this species.