Strategies for optimizing targeting and delivery of mucosal HIV vaccines

Effective frontline defenses against HIV-1 will require targeting vaccines to mucosal tissue in order to induce alphabeta CD8(+) lymphocytes in mucosal effector sites (lamina propria and intraepithelial compartment) as well as antibody secreting plasma cells that can neutralize and limit free virus. A concerted second wave of assault against the virus will require the activation and recruitment of antigen specific memory CD4(+) and CD8(+) T cells in mesenteric lymph nodes and distal secondary lymphoid organs. New delivery strategies targeting the "right" DC subsets in combination with delivery of mucosal adjuvants and innate signals for activating DC will be essential for mucosal vaccines in order to circumvent the naturally tolerogenic environment and the induction of Tregs. Mucosal delivery of antigen in combination with inflammatory signals has been shown to empower systemic immunization by directing responses to mucosal sites for imprinting optimum mucosal memory. Here, we discuss novel vaccine strategies and adjuvants for optimizing mucosal delivery of HIV vaccines.