vIRF3 and HLA class II expression by PELs and expression of CIITA and HLA class II after CIITA transduction. (A) Western blot analysis of lysates from PELs probing for vIRF3 expression (top) or for the HLA DRα chain expression (bottom) and calregulin expression as a loading control. (B) Western blot analysis of lysates from Cont–transduced or CIITA-transduced PELs, probing for CIITA, HLA-DRα, and calregulin as a loading control. (C) Flow cytometry analysis of surface HLA class II levels on BCBL-1, an LCL or a fibroblast (top left), VG-1 transductants (top right), BC-1 transductants (bottom left), and JSC-1 transductants (bottom right). CIITA-transduced PELs are shown in black, nontransduced PELs in gray, and isotype control staining is open.