FIG 5.

Impairment of STAT3 function causes death of EBV-infected cells and lower transcript levels of STAT3 targets but not of LMP1. (A) B cells from healthy EBV-seronegative subjects were infected with EBV in the absence (black bars) or presence (open bars) of AG490; B cells from AD-HIES patients were also infected with EBV (gray bars). Cells were harvested on day 2 and evaluated by flow cytometry for expression of LMP1 and staining with annexin V. Percent annexin V⁺ cells within LMP1⁺ and LMP1⁻ populations was calculated, and aggregate data from six healthy and six AD-HIES patients are shown. (B and C) Cells were harvested 24 h after infection of healthy B cells, and relative levels of LMP1 mRNA (B) and mRNA from genes that are known transcriptional targets of STAT3 (Bcl-xL and Bcl-2) and STAT1 (IRF1) (C) were determined by qRT-PCR. Solid bars, EBV; open bars, EBV+AG490. Data from three experiments and three technical qRT-PCR replicates are incorporated for each data point. All error bars = SEM; N.S., not significant. (D) Infections were performed as described for panels B and C. Twenty-four hours after infection, intracellular levels of STAT3 were determined by flow cytometry. Solid line, EBV; dashed line, EBV+AG490.