ERVW-1 and Epstein-Barr virus infection: Interestingly, Sutkowski et al. found that EBV infection transactivates the expression of HERV-K18 env gene that possesses SAg activity, which was further demonstrated by MHC class II dependent preferential activation of TCRVB13 T cells in response to murine B cells transfected with the HERV-K18 env gene37.