Data from the rhesus macaque model indicates that HIV-1 Env specific neutralizing antibodies protect against mucosal [1–3] and intravenous SHIV challenge [4, 5], as well as from heterologous SIV challenge [6] reducing the pathogenic effects of infection such as CD4+ T-cell loss, and the viral set-point [1, 4, 6]. The gene discussed is ERVW-1; the disease is infection.