ERVW-1 and HIV-1 infection: T lymphocyte depletion associated with HIV-1 infection involves the death of infected cells, but is mainly due to the selective destruction of uninfected cells.2, 3, 4, 5 This process, also known as by-stander killing, can be induced by viral incomplete reverse transcripts or proteins, such as the HIV-1 envelope complex (Env), Tat, Nef, Vpu and Vpr,6, 7 by excessive T lymphocyte activation8 or by abortive infection6, 9 of immune cells.