The glycobiology of implantation

Embryo implantation involves complex, coordinated interactions of cell surface components of embryonic (trophectoderm/trophoblast) and uterine cells. Oligosaccharides are common constituents of cell surface molecules. A variety of oligosaccharide structures have been identified at embryonic and uterine cell surfaces and change dynamically during progression of the implantation reaction. In many cases, the oligosaccharides have been shown to have biological activities with great relevance to the implantation process. This review summarizes the available information on glycoconjugates as it relates to the implantation process. It is suggested that carbohydrate bearing molecules at embryonic and uterine cell surfaces play diverse roles during the implantation process that are similar to the roles suggested for these molecules in other biological contexts.