T cell-mediated hepatitis can be induced in rodents by injection of concanavalin A (ConA): a lectin, originally extracted from Canavalia brasiliensis plant, which rapidly induces clinical and histological hepatitis, including up regulation of transaminase activity and CD4+CD69+ T cells and down regulation of NK1.1+ and CD3+ NKT cells within 24 h (Hines et al., 2007). This evidence concerns the gene CD4 and hepatitis A virus infection.