Delivery systems and adjuvants for vaccination against HIV

Epidemiological studies have revealed that HIV-1 infections occur through contact with contaminated blood or during unprotected vaginal or anal intercourse. Hence, to protect against HIV infection, vaccines should ideally induce both mucosal and systemic immune responses. We present a brief review of the different delivery systems and adjuvants which can be used to elicit mucosal immune responses. Oral or nasal administration of recombinant attenuated bacteria or viruses can induce both mucosal and systemic immune responses against the carried antigen. The oral delivery of mucosal adjuvants (such as cholera toxin) in association with antigens has been shown to enhance mucosal and systemic immune responses against them. Recently developed vaccination strategies using naked DNA or other antigen delivery systems are also discussed.