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The carbohydrate H-type-1 antigen has been implicated in attachment of the murine blastocyst to the endometrial epithelium. Monoclonal antibody 667/9E9 was used to investigate the steroidal dependency of expression of this antigen in the murine endometrial epithelium using intact or ovariectomized mice treated with oestrogen or the pure anti-oestrogen, ICI 182,780. The effects of this anti-oestrogen were also investigated in the endometrial epithelium from intact rats. In both ovariectomized, oestrogen-supplemented and intact mice after treatment with ICI 182,780, staining with monoclonal antibody 667/9E9 was abolished in the luminal epithelium on both the apical and lateral cell surfaces, whereas basal staining remained. Glandular staining in mice was not affected in the same manner. In intact rats, where H-type-1 antigen expression has been reported to be predominantly controlled by progesterone, the anti-oestrogen had little effect, in accordance with previous reports.

Biotinylated lectins from Sambucus nigra (SNA) and Maackia amurensis (MAA), which bind to alpha 2,6-linked and alpha 2,3-linked sialyl residues, respectively, were used as probes to study glycan terminal modifications associated with decidualization in the uterine stroma of pregnant rats and mice. Binding of lectins from Erythrina cristagalli (ECA), Phaseolus vulgaris (leukoagglutinin, L-PHA), Triticum vulgaris (WGA) and Bandeiraea simplicifolia (BSA-1B4) was also examined. Tissues from rats between day 5 and day 8 of gestation and mice between day 5 and day 7 of gestation were fixed in Bouin's solution and embedded in wax prior to lectin histochemistry. On day 7 in rats and day 6 in mice, there was a marked reduction in the binding of SNA in the subluminal decidua surrounding the implantation site. In rats, MAA binding to enlarged decidual cells around the implantation chamber was increased markedly, but there was no change in mice. In both species there was de novo binding of ECA in the SNA-negative area, suggesting that the loss of alpha 2,6-linked sialyl residues unmasks terminal N-acetyl lactosamine. These findings are consistent with previous evidence of a close structural and functional similarity between the artificially induced deciduoma and true decidua of rats and show identical changes to the glycosylation patterns previously found in differentiating rat deciduoma. In both species, therefore, decidua exhibits regionally specific terminal glycosylation. However, the species-specific expression of alpha 2,3-linked sialyl residues suggests distinct patterns of steroidally modulated sialyl transferase expression.

Monoclonal antibodies were used to examine the expression of a number of carbohydrate antigens in the rat endometrial epithelium from day 1 to day 8 of pregnancy and in ovariectomized rats supplemented with ovarian steroids. Carbohydrate antigens based on the Gal beta 1-GlcNAc backbone structure were expressed and some of these (Le(y), Le(x), B antigen) were present at all stages of pregnancy and independent of ovarian steroids. The H-type-2 antigen was stimulated by progesterone and expressed in the sensitized and receptive uterus, but was not detected after implantation or, in ovariectomized rats, in the refractory phase. The H-type-1 antigen, which is stimulated by oestrogen in the mouse, appeared to be stimulated by progesterone in rats. It was expressed throughout the period of pregnancy but maximal expression was found on days 4-5. The histo-blood group A antigen appeared in ovariectomized rats only after treatment with progesterone followed by three daily injections of progesterone and oestrogen, and in the corresponding postimplantation period of pregnant rats. Its appearance corresponded to the loss of detectable H-type-2 antigen. This study shows that the rat endometrial epithelium expresses some carbohydrate antigens not expressed in mice (A and B antigen) or under completely different steroidal regulation (H-type-1). Moreover, the T antigen was expressed on the endometrial epithelium adjacent to decidua on days 7 and 8 of pregnancy, but not in rats given ovarian steroids to mimic the sensitized, receptive or refractory phase. Differences in expression between glandular and luminal epithelial indicated differences in steroidal regulation, as found in mice.

This present paper further evidence for the presence of a receptor for lacto-N-fucopentaose I on the mouse trophectoderm.

Seven oligosaccharides isolated from human milk were tested for their effect in an in-vitro model of mouse blastocyst adhesion and trophoblast outgrowth on endometrial epithelial monolayers. One compound, lacto-N-fucopentaose I (LNF I), produced a significant reduction in the percentage of attached and outgrown blastocysts after co-culture for 72 h (P less than 0.001). No significant effect of any other tested oligosaccharide was obtained.