Two mucosal–parenteral schedules to coadminister a multiantigenic formulation against HIV-1 in Balb/c mice

Previous studies showed that simultaneous immunization through the nasal (IN) and subcutaneous (SC) route of a multiantigenic formulation induced a Th1 anti-HIV humoral and cellular immune responses. The formulation was comprised of a recombinant protein of HIV-1 (named CR3; Cellular Response number 3) and the surface and nucleocapsid antigens of hepatitis B virus. This study asks whether four times simultaneous administration through the IN and SC routes (SC + IN) of the multiantigenic formulation induces a similar systemic and mucosal immune responses than two sequential IN priming and two SC boosting (2IN&2SC) inoculations in mice. To answer this question, we tested the same total dose of each antigen per animal in both schedules of inoculation. We found that SC + IN and 2IN&2SC coadministration induced comparable levels of CR3(HIV)-specific IFN-γ-secreting cells and CD8 + cells proliferation in the systemic compartment of animals. Consistent with these findings, a similar Th1 profile considering anti-CR3 IgG1:IGg2a ratio was observed. Additionally, the level of IgG antibodies and the frequency of seroconverting animals in vagina were not different. However, in the case of IgA antibodies the same parameters were significantly higher in the SC + IN group. We also found important level of HBsAg-specific antibodies in serum and vaginal washes.

► Simultaneous IN and SC inoculation versus two IN priming and two SC boosting.
► Both schedules induce similar levels of IFN-γ-secreting cells and CD8 + cells.
► IgG antibodies and frequency of seroconverting animals in vagina are also similar.
► More IgA antibodies in vagina with simultaneous IN and SC inoculation.