Identification and characterization of glycosylation-dependent cell adhesion molecule 1-like protein expression in the ovine uterus

Glycosylation-dependent cell adhesion molecule 1 (GlyCAM-1) is an endotheli al glycoprotein secreted in lymph nodes that sen;es as a ligand for leukocy te cell surface selectin and mediates lymphocyte extravasation. In the pres ent studies, rabbit anti-rat GlyCAM-1 IgG was used in immunochemical analys es of GlyCAM-1-like protein in the ovine uterus. In cyclic ewes, GlyCAM-1 e xpression increased in the endometrial luminal epithelium (LE) and shallow glandular epithelium (cGE) between Days 1 and 5 and then decreased between Days 11 and 15. In pregnant ewes, GlyCAM-1 in the LE and cGE was low on Day s 11 and 13, increased on Day 15, and was abundant on Days 17 and 19. Immun oreactive GlyCAM-1 was also detected in the conceptus trophectoderm on Days 13-19. Staining for GlyCAM-1 in the smooth muscle of the vasculature and m yometrium was constitutive, and no staining was detected in the stroma. An immunoreactive protein of similar to 45 kDa was identified in endometrial e xtracts and uterine flushings from cyclic and pregnant ewes. In pregnant ew es, the relative amount of immunoreactive GlyCAM-1 in uterine flushings was low on Days 11 and 13 but high on Days 15 and 17. Results suggest that a G lyCAM-1-like protein may be a secretory product of the endometrial epitheli um and/or conceptus trophectoderm. Patterns of distribution observed for im munoreactive GlyCAM-1-like protein in the endometrial epithelium, combined with proposed functions for lymphoid GlyCAM-1, suggest that this mucin glyc oprotein may be involved in conceptus-maternal interactions during the peri implantation period of pregnancy in sheep.