Induction of dendritic cell-mediated immune responses against HIV-1 by antigen-capturing nanospheres in mice

Prophylactic vaccines, designed to elicit potent humoral and cellular immune responses to human immunodeficiency virus type 1 (HIV-1) antigens in mucosa, are the important approach to the protection of individuals against HIV-1 infection, since HIV-1 transmission is largely a result of sexual contact. In this study, a novel strategy has been developed to induce HIV-1-specific immune responses, which involves inactivated HIV-1-caputring concanavalin A (Con A)-immobilized nanospheres (HIV-NS) and their interaction with bone marrow (BM)-derived dendritic cells. HIV-NS were taken up by dendritic cells via cytoskeleton-dependent but mannose-binding site-independent phagocytosis. Serial stimulations to unprimed T-cells with HIV-1 gp120-capturing NS-pulsed dendritic cells could induce antigen-specific T-cell response. Intranasal administration of fluorescein isothiocyanate-labeled nanospheres (NS) in mice proved that the particles were taken up into pulmonary dendritic cells. Analysis of mice receiving intranasal immunizations with HIV-NS revealed that the mice efficiently induced the antibodies against HIV-1 in the genital tract and specific cytotoxic T-cells in the spleen. These results suggest that the use of HIV-1-NS may provide a novel and promising approach for the induction of humoral and cellular immune responses to HIV-1.