IRF-4 and Tax protein expression in primary ATLL tumors before and after cell culture. (A) Western blot analysis demonstrating Tax and IRF-4 protein status in primary unmanipulated and cultured ATLL tumors. (B) In selected patients, IRF-4 and Tax protein expression was measured ex vivo before cell culture (day 0) and on in vitro culture for the indicated time periods (day 1, 24 hours; day 2, 48 hours; day 3, 72 hours). Whole cell lysates from MT-2 and Jurkat lines were used as positive and negative controls, respectively. *Tumors from patients in whom AZT and IFN-α therapy failed.