Figure 3

Involvement of PKR in IFN-α-mediated reduction of Tax protein levels in HTLV-1-infected cells. A. ILT-Hod and ILT-#29 cells were incubated with or without the PKR-inhibitor (500 nM) or the negative control-inhibitor (500 nM) for the first 2 h, then further cultured for the next 24 h in the presence or absence of IFN-α (3000 IU/ml) as indicated. Flow cytometry was then performed following stained with anti-Tax (open histogram) and isotype control (closed histogram) antibodies. B. HTLV-1 pX mRNAs in the same samples prepared in A were quantified by RT-PCR using two different primer sets (RPX; black bar, and pX; gray bar), standardized to GAPDH mRNAs, and the relative values were indicated as the means and SD of duplicate samples. C. PKR mRNAs in ILT-Hod, ILT-#29, and HTLV-1-negative Jurkat and MOLT4 cells were quantified by RT-PCR, standardized to GAPDH mRNA and indicated as the means and SD of duplicate samples. D. PKR mRNAs in ILT-Hod and ILT-#29 cells were quantified 24 h after culture in the absence (open bar) or presence (closed bar) of IFN-α (3000 IU/ml), and the relative values are indicated as the means and SD of duplicate samples. *p < 0.05.