Comparison of intranasal with targeted lymph node immunization using PR8-Flu ISCOM adjuvanted HIV antigens in macaques

The rapidly spreading HIV epidemic requires a vaccine that elicits potent mucosal immunity to halt or slow transmission. Induction of these responses will depend on the use of appropriate adjuvants and targeting of the mucosal immune system. Previously, immune stimulating complexes (ISCOM) have shown great potency as adjuvant in the induction of mucosal responses in mice and systemic responses in non‐human primates. In this study, HIV formulated in PR8‐Flu ISCOM adjuvant was applied to immunize rhesus macaques against HIV; targeting the mucosa either via intranasal (IN) application or via targeted lymph node immunization (TLNI). While, strong systemic, HIV specific, cytokine, lymphoproliferative, and antibody responses were induced via the TLNI route, the IN application generated only low responses. Furthermore, all four animals immunized via TLNI developed vaginal IgA antibodies against gp120. In conclusion, in contrast to what has been demonstrated in mice, the IN application of PR8‐Flu ISCOM did not induce strong immune responses in rhesus macaques unlike those immunized by the TLNI route. J. Med. Virol. 79:474–482, 2007. © 2007 Wiley‐Liss, Inc.