HIV-1 infection is initiated by binding of the viral envelope glycoprotein (Env), a trimer consisting of the gp120 and gp41 subunits, to CD4 on CD4+ T cells, facilitated by cellular coreceptors (e.g., CXCR4 or CCR5) to trigger membrane fusion (1, 2). This evidence concerns the gene ERVW-1 and HIV-1 infection.