Pregnancy-related changes in the human endometrium revealed by lectin histochemistry

The binding of 22 fluorescein isothiocyanate (FITC) conjugated lectins to human proliferative phase and pregnant endometrium was studied histochemically. Only the lectin from Bauhinia purpurea (BPA) reacted exclusively with the epithelial cells. All the others reacted to a certain extent with glandular and/or stromal cells. Lectins from soybean (SBA), and Vicia villosa seeds (VVA) reacted with endometrial glands of pregnancy but not with the glands of the proliferative endometrium. In the proliferative endometrium SBA reacted only with cells of the surface endometrium. Lectin from peanuts (PNA) reacted only with some glands in the proliferative endometrium but was unreactive with others. In pregnant endometrium PNA reacted with all glands. Lectins from lentils (LCA) and red kidney beans (PHA-E and PHA-L) reacted with endometrial glands of the proliferative phase but not with the glands from pregnant endometrium. We thus show that FITC labeled lectins define specific carbohydrate moieties selectively expressed on either proliferative phase or pregnant endometrial glands.