Synthetic carbohydrate antigens for HIV vaccine design

Carbohydrates account for about half of the molecular mass of the envelope glycoprotein gp120. This heavy glycosylation constitutes a strong defense mechanism for viral evasion. Nevertheless, the discovery of more than a dozen of glycan-dependent broadly HIV-neutralizing antibodies from HIV-infected individuals suggests that the defensive viral “glycan shield” can also serve as important targets of vaccines. A major issue in further characterization of the detailed structures of the neutralizing epitopes and the reconstitution of the epitopes for vaccine development is the heterogeneity of HIV glycosylation, which is difficult to control in recombinant glycoprotein production. Synthesis of defined carbohydrate antigens provides an important approach to epitope characterization and design of epitope-focused HIV vaccine. This chapter provides a brief description on the challenges in HIV vaccine development, the features of HIV glycosylation, and why synthesis of novel carbohydrate antigens represents a promising approach to HIV vaccine design.