FIG. 8.

Flow cytometric analysis of Stat1 phosphorylation in human tonsil T cells stimulated with IFN-γ. Column-purified human tonsil T cells were cocultured with VZV-infected HEL monolayers. After 48 h, cells were removed from the monolayer and either left unstimulated (A) or stimulated with recombinant human IFN-γ for 10 min at 37°C (B). Cells were fixed in paraformaldehyde, stained with antibodies and fluorescent conjugates to VZV proteins, permeabilized in methanol, and then stained with antibodies to phospho-Stat1 and CD3. FACS plots show anti-phospho-Stat1 versus anti-VZV staining of uninfected (left plots), pOka-infected (middle plots), and pOka66S-infected (right plots) tonsil T cells (gated on CD3⁺ cells) without stimulation (A) or following stimulation with IFN-γ (B). (C) Data from T cells cultured for 48 or 72 h with infected HEL monolayers are shown as the average fold increase in phospho-Stat1 fluorescence intensity following IFN-γ treatment in VZV-infected and uninfected T cells for four independent experiments done after 48 h and two experiments combined for 72 h. One asterisk indicates a fold increase that is significantly different from that of uninfected cells from the same culture with P = 0.01, while two asterisks indicate a difference with P = 0.02.