ERVW-1 and infection: The passive transfer of Env-specific neutralizing monoclonal antibodies can protect against viral challenge in non-human primates, suggesting that they would be able to prevent human infection if present at the sites of exposure (Mascola et al., 1999; Parren et al., 2001; Hessell et al., 2009; Rosenberg et al., 2013; Shingai et al., 2014).