To investigate whether Bim downregulation by Tax is involved in the transformation of CTLL-2 cells, we established Bim-knockdown CTLL-2 cells by infection of lentivirus expressing shRNA targeting Bim. BimEL and BimL were efficiently knocked down in these cells, but the levels of other Bcl-2 family proteins, Bax and Bcl-xL, were not affected (Fig. 3A). Here, BCL2L1 is linked to infection.