ERVW-1 and immunodeficiency disease: For example, certain viral antigens expressed at the surface of infected cells, such as envelope glycoproteins (Env) of immunodeficiency-inducing viruses, like HIV, or of cancer-inducing viruses, like HCV or murine oncoretroviruses, may also permit mAbs to target virus reservoirs via complement-dependent- (CDC) or antibody-dependent cell cytotoxicity (ADCC) mediated by natural killer cells.