The availability of unique carbohydrate reagents combined with new techniques to assay the interaction between carbohydrate ligands and their receptors has led to a dramatic increase in recent discoveries of the biological functions of complex carbohydrates. A new field, Glycobiology, has emerged which combines expertise in both carbohydrate biochemistry and molecular biology. Carbohydrate sequences contain much structural information which is exploited in many forms of biological recognition. Examples of the interaction of cells with cytokines, hormones, toxins, antibodies, lectins, bacteria, viruses, and other cells have all been demonstrated to involve carbohydrate recognition. As secondary gene products, changes in the structures of cell surface carbohydrates are particularly sensitive to conditions of the cell's biology, such as the state of differentiation, cell cycle, or growth conditions. Both the amount and types of glycosyltransferases that exist in the cell are responsible for variable surface expression of carbohydrate structures. Competition among the enzymes in these complex biosynthetic pathways act as switches to regulate the expression of carbohydrate structure. Thus, the high degree of structural information combined with intricate controls for their expression bestow carbohydrates with the required properties to act as recognition molecules.

As recognition molecules, carbohydrates structures play critical roles in many biological functions. Identification of these bioactive carbohydrates presents a timely opportunity for carbohydrate biochemists to determine the precise functional domain of the carbohydrate ligand for the development of a new class of phamaceutical reagents. Advantages of these new pharmaceuticals over traditional drug candidates are the application of directed rational drug design, a high degree of specificity, greater efficacy, and the development of strong proprietary positions.