IL4 and infective vaginitis: CD4 T cells recovered from the FRT at day 14 post vaginal infection were assessed by flow cytometry following brief PMA/ionomycin stimulation in the presence of Brefeldin A. As expected, CD4 T cells in the FRT of Chlamydia-infected mice produced significant amounts of IFN-γ, but negligible IL-4 (Fig 1A and 1B).