FIG. 4.
Effect of rotavirus Ag on the induction of Th1-type (IFN-γ) and Th2-type (IL-4 and IL-6) cytokine secretion by unfractionated cells (A) and CD4+ T cells (B) from PP of IL-6− (open bars) and IL-6+ (solid bars) mice (BALB/c background) orally inoculated with RRV (107 FFU). Cells were isolated from mice 6 weeks after rotavirus infection and restimulated in vitro with RRV Ag (1:102 dilution). Cytokine levels shown are from 4-day culture supernatants as determined by ELISA and represent three experiments of three to five mice per experiment (± SD). ∗, P < 0.01 versus mock-stimulated cells. ∗∗, P < 0.01 versus mock-stimulated cells from IL-6−/− mice. The significant increase in IL-4 in CD4+ T cells was not observed in culture supernatants at days 2 and 6 (data not shown). Similar results were obtained with IL-6− and IL-6+ mice of a mixed (C57BL/6 × O1a)F2 background (data not shown).