Recent studies have revealed that carbohydrate units on cell surfaces play hey roles in cell-cell recognition processes. Fertilization begins with the binding of a sperm to a specific oligosaccharide on the surface of an egg. The adhe- sion of leukocytes to the lining of injured blood vessels and the return of lymphocytes to their sites of origin in lymph nodes further illustrate the importance of carbohydrates in recognition processes. Carbohydrates have entered the limelight as information-rich molecules, full of signifi cance in development and repair