FIG 4.

Effects of intragastric immunization with the attenuated Chlamydia on chlamydial infectivity in the genital tract. Groups of C57BL/6J mice intragastrically inoculated with CMwt (a, n = 6), CMpGP3S (b, n = 8) or CMpf (c, n = 8) as described in Fig. 3 legend plus a SPG buffer immunization control group (d, n = 5) were all challenged with CMwt via intravaginal inoculation on day 56 after the intragastric immunization. All mice were monitored for Chlamydia shedding from the genital tract via vaginal swabbing on days 3, 7 and weekly thereafter following the challenge infection. The results were expressed as Log₁₀ IFUs per swab. The numbers of mice detected positive for IFU were indicated in parenthesis if not all mice in the group were either positive or negative for IFU. Note that mice orally immunized with either wild type or mutant Chlamydia organisms were protected from genital tract infection (*P < 0.05, **P < 0.01, Wilcoxon for comparing AUC or IFUs at different time points).