Differential expression of BLIMP1α in normal and transformed GC B cells. (A) Quantitative RT-PCR analysis shows that EBV infection of GC B cells was associated with the down-regulation of BLIMP1α transcription. Shown here are 3 LCLs (SL1-LCL, SL2-LCL, and SL3-LCL) established after the infection of GC B cells isolated from 3 separate donors. (B) Immunohistochemical analysis revealed strong BLIMP1 expression in a subpopulation of the uninfected GC B cells. In contrast, the LCLs showed homogeneously weaker BLIMP1 expression. Magnification ×450. Images acquired with 60×/1.40 NA oil immersion objective lens (Nikon Ltd).