ERVW-1 and HIV-1 infection: There is also evidence from experiments with monoclonal antibodies derived from B cells of RV144 vaccinees that HIV-1 Env IgA blocks ADCC-mediating antibodies, consistent with the findings that ADCC correlated with decreased risk of HIV-1 infection when Env IgA was low and that an elevated IgA/IgG ratio correlated with HIV-1 risk (8).