HTLV-1 Infection (IMAGE) Kyoto University Caption HTLV-1 establishes infection mainly in CD4+ T cells and induces leukemia. HTLV-1-encoded Tax is a critical transactivator of viral replication, but its significance in pathogenesis remained unclear. The research team showed that Tax is expressed in a fraction of leukemic cells and its expression spontaneously switches between on and off states. Credit Kyoto University / Jun-ichirou Yasunaga Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.