[Immune Effects and Mechanisms of HIV-specific Antibodies Against Viral Infection]

Broadly neutralizing antibodies (bNAbs) have demonstrated a protective role from experimental challenge in non-human primates and humanized mouse models. Recently, bNAbs 3BNC117 and VRC01were assessed in a phase-I clinical trial, and were shown to lower plasma viremia in human immunodeficiency virus(HIV)-1-infected individuals not receiving antiretroviral therapy. However, induction of these types of antibodies by vaccination iS extremely difficult. Moreover, the 31% protection observed in the RV144 vaccine trial in the absence of detectable bNAbs in blood samples suggested the important role of additional inhibitory functions of the antibodies that control infection and replication of HIV. Increasing evidence suggests that immunoglobulin-G Fcγ receptor-mediated inhibition of antibodies present at the mucosal site may have a protective role against mucosal transmission of HIV. Dendritic cells and macrophages express such Fc receptors on their surface, and may have a decisive role in early mucosal transmission because they have been proposed to be the first HIV target at the mucosal site. Therefore, new vaccination strategies involving induction of such non-neutralizing inhibitory antibodies and other antiviral functions, in addition to bNAbs, should be developed.