ANTI-GP120 MINIBODY GENE TRANSFER TO FEMALE GENITAL EPITHELIAL CELLS PROTECTS AGAINST HIV-1 VIRUS CHALLENGE IN VITRO.

Background:  Although cervico-vaginal epithelial cells of the female lower genital tract provide the initial defense system against HIV-1 infection, the protection is sometimes incomplete. Thus, enhancing anti-HIV-1 humoral immunity at the mucosal cell surface by local expression of anti-HIV-1 broadly neutralizing antibodies (BnAb) that block HIV-1 entry would provide an important new intervention that could slow the spread of HIV/AIDS. Methods and Findings:  This study tested the hypothesis that adeno-associated virus (AAV)-BnAb gene transfer to cervico-vaginal epithelial cells will lead to protection against HIV-1. Accordingly, a recombinant AAV vector that encodes human b12 anti-HIV gp120 BnAb as a single-chain variable fragment Fc fusion (scFvFc), or ‘‘minibody’’ was constructed. The secreted b12 minibody was shown to be biologically functional in binding to virus envelope protein, neutralizing HIV-1 and importantly, blocking transfer and infectivity of HIV-1bal in an organotypic human vaginal epithelial cell (VEC) model. Furthermore, cervico-vaginal epithelial stem cells were found to be efficiently transduced by the optimal AAV serotype mediated expression of GFP. Conclusion:  This study provides the foundation for a novel microbicide strategy to protect against sexual transmission of HIV-1 by AAV transfer of broadly neutralizing antibody genes to cervico-vaginal epithelial stem cells that could replenish b12 BnAb secreting cells through multiple menstrual cycles.

Cell-free virus, EpiVaginal™ tissues (VEC-100: Nunc), HIV interactivity, HIV transfer, HIV-1 microbicide, P24, Transepithelial electric resistance (TEER), Virus challenge

AAV-6 expressing b12 minibody, AAV-6-11A minibodies, B12 minibodies, Dextran-Rhodamine B (70 kDa), HIV-1bal