EXPRESSION OF THE CARBOHYDRATE ANTIGEN CD15 IN RAT UTERINE EPITHELIAL-CELLS DURING THE EARLY STAGES OF PREGNANCY

The presence and distribution of the carbohydrate antigen CD15 in rat uterine epithelial cells was determined using immunohistochemical loca lisation at both light and electron microscopical levels. Rat uterine tissue was examined on days 1, 3 and 6 of pregnancy and it was found t hat expression of CD15 was highly stage specific with negligible detec tion on days 1 or 3 of pregnancy but very strong expression at both li ght and electron microscopic levels on day 6. Electron microscopy usin g ferritin as marker revealed expression in the glycocalyx of at the p lasma membrane of uterine epithelial cells. This strongly stage-specif ic expression of CD15 and the extracellular surface localisation sugge sts an important role for this antigen during the early stages of preg nancy in the rate and implicates the molecule in attachment to the ute rine epithelium.