IL-13 increases HCMV antigen production in alveolar macrophages. Alveolar macrophages cultured at a density of 1 × 106 cells/well for 7 days were pretreated with the indicated concentrations of IL-13 for 2 days before virus challenge. The cells were then exposed to HCMV Davis (MOI of 1) for 4 hours, washed 3× with PBS and refed with growth medium containing the same concentrations of IL-13. Cells were fixed at day 5 postinfection and probed by immunocytochemical staining using antibodies against either HCMV immediate early (IE) antigen (A), or late nuclear antigen (LNA) (B). The numbers of antigen-expressing cells were quantitated by light microscopy at 200× magnification. Data are derived from 3 wells from 3 different experiments. Statistically significant differences from the control were determined by employing the Student's t-test. * = P < .05; ** = P < .01; *** = P < .001.
