C57BL/6 (n=17) (A), TLR5−/− (n=14) (B), Naip5−/− (n=9) (C), and Casp1−/− (n=11) (D), TLR5−/−/Casp1−/−, DKO (n=9) (E), MyD88−/− (n=11) (F) mice were immunized on day 1 and day 21 and sera was collected on days 0 (naïve), 14 and 35. Naïve and day 35 sera (boost) were analyzed for IgA specific antibody responses against FliC by ELISA. Data is a combination of 2–3-independent experiments with n = 3–6 per experiment. Statistical analyses were done using Mann-Whitney analysis of individual groups: *= P < 0.05, *** = P < 0.001.