Analyses of intracellular CXCR4 protein and CXCR4 mRNA content of uninfected and HHV-7–infected SupT1 cells. (A) Flow cytometric analysis of intracellular CXCR4, either alone (top panels) or in combination with surface CXCR4 (bottom panels), in uninfected and HHV-7–infected (8 days PI) SupT1 cells. Horizontal axis, relative intracellular CXCR4 expression detected by PE fluorescence intensity; vertical axis, isotype-matched antibody staining or relative surface CXCR4 expression detected by FITC fluorescence intensity. Percentages of cells in the respective quadrants are indicated. The profile of the negative controls, represented by SupT1 cells stained with irrelevant isotype matched MoAb, were as shown in Fig 1B (top panel). The data are representative of four experiments from separate infections. (B) Semiquantitative RT-PCR specific for CXCR4 mRNA was applied to analyze CXCR4 mRNA levels in HHV-7–infected SupT1 cultures (8 days PI) as compared with the uninfected cells. β-Actin amplification was used to confirm comparability of the samples. Equivalent amounts of RNA extracted from uninfected and HHV-7–infected cells were used for 1:3 limiting step dilution (lanes 1 through 4) before RT-PCR with the CXCR4 and β-actin primers. Ethidium bromide-stained agarose gel of RT-PCR products is shown. Lanes −, amplification of the indicated RNA template performed before RT; lane BL, blank.