Fig 5. The emrA1 mutant vaccinated mice induce sustained production of pro-inflammatory cytokines and a potent antibody response following lethal Ft LVS challenge.

C57BL/6 mice immunized i.n. with 1×10⁶ CFU of the emrA1 mutant were challenged i.n. with 1×10⁷ CFU of wild type Ft LVS 42 days post-immunization. (A-D) On days 5, 7 and 14 post-challenge, mice (n = 3 per group/time point) were euthanized and their excised lungs were homogenized. Clear lung homogenates were used for quantification of indicated pro-inflammatory cytokines using flow cytometric analysis. The data are represented as Mean ± S.D. (E) On day 21 post-challenge, mice (n = 3 per group) were anesthetized and bled retroorbitally to obtain serum. Ft specific total IgG, IgG2a, IgG2b, IgG1 and IgA levels in serum samples were determined by ELISA. The data are represented as Mean ± S.D. of absorbance values measured at 450 nm. Red arrows indicate antibody titers. ND = Not detected.