IL-17 As A Molecular Adjuvant On Enhancing Cellular Immune Responses To HIV DNA Vaccination

Members of the IL-17 family are central players in various arms of the adaptive immuneresponse and have become key to an expanded understanding of cytokine networks that coordinate innate and adaptive immunity to certain pathogens. IL-17 cytokines are also key mediators in a diverserange of auto-in?ammatory disorders. IL-17 is proinflammatory cytokine secreted by a unique CD4+ T (T-help) cell subset and proposed to play arole in host defense. We hypothesized that IL-17 as a molecular adjuvant on enhancing immuneresponses to HIV DNA vaccination.To improve the immuneresponse to HIV DNA vaccine, we investigated IL-17 as adjuvant effect on the humoral and cellular immuneresponses to HIV DNA vaccine by immunizing mice with HIV DNA vaccine plus IL-17. We immunized the BALB/c mice with pGX-Env alone, or with pcDNA3-IL-17 by intramuscular injection. The immunization was performed on week 0, 2. The concentration of the anti-Env IgG , the stimulated index of T lymphocyte proliferation , and the expression of IFN-γ, IL-4 and IL-17 in CD4 + T cell and IFN-γin CD8+ T cell, specific in vivo cytotoxic T lymphocyte (CTL) activity were detected at week 4. We show here that IL-17 as a molecular adjuvant with the HIV DNA vaccine, pGX-Env, can enhance immuneresponses. Interestingly, IL-17 has no adjuvant effect on theresponses for T cell proliferation, antibody production and expressions of IFN-γ, IL-4 and IL-17 in CD4+ T cells, butrather on the up-regulation of IFN-γin CD8+ T cells and CTL in vivo significantly (P<0.05) .The data suggest that IL-17 as the molecular adjuvant may not affect the development and differentiation of CD4+ Th cells, but directly affect on the CD8+ T cell functions. The novel functionality of IL-17 on adaptive immunity may lead to develop effective HIV DNA vaccination targeted to potentiate the CD8+ T cell functions.