Induction of mucosal IgA following intravaginal administration of inactivated HIV-1-capturing nanospheres in mice.

Concanavalin A-immobilized polystyrene nanospheres (Con A-NS) were developed for the HIV-1 vaccine capable of preventing sexual transmission. Con A-NS could capture efficiently HIV-1 irrespective of their cell tropism (R5 or X4). Furthermore, Con A-NS captured equally infectious and heat-inactivated HIV-1. Inactivated HIV-1-capturing Con A-NS (HIV-NS) were intravaginally administered to mice. Heat-inactivated HIV-1 alone and Con A-NS alone were also administered as control immunogens. Vaginal fluids were collected during and after immunization and analyzed for their anti-HIV-1 antibody levels. Although the anti-HIV-1 IgG antibody was undetectable in any groups, increased anti-HIV-1 IgA antibody response was identified in the vaginal fluids of immunized mice with HIV-NS. The vaginal fluids obtained from the HIV-NS-administered mice showed neutralizing activity against the immunizing HIV-1 strain. A marked difference in vaginal distribution was observed between HIV-NS and other immunogens, and the toxicity of Con A was reduced by conjugation with nanospheres. Thus, HIV-NS may have great potential as a prophylactic HIV-1 vaccine and should be examined further for its efficacy in non-human primates.