ABSTRACT
The sequence of cell adhesion events occurring during implantation of the mammalian embryo is described, concentrating on data from mouse and human. Changes occurring in the luminal endometrial epithelium prior to implantation are dissected. The analogy is explored between initial attachment of trophoblast to the uterine epithelium and that of neutrophils to the endothelial lining of blood vessels at sites of inflammation. The possible role of various carbohydrate ligands in initial attachment of the blastocyst is reviewed. The evidence for subsequent stabilization of cell adhesion via integrins is discussed. In spite of many years of research, the precise sequence of events during interaction of the embryo with the uterus is still not clearly understood.
