ERVW-1 and infection: One strategy focused on eliciting neutralizing antibodies with HIV envelope glycoproteins (Env) to block infection; another strategy focused on inducing T-cell responses with conserved, internal viral proteins (such as HIV gag, nef, and pol); the third strategy tried to generate both humoral immunity and cellular immunity through heterologous prime/boost procedure (such as prime with a DNA vaccine and boost with an Ad vaccine vector) [37,38,39,40].