Fig. 3

Humoral immune response in non-restricted mouse models. a Purified hFliC protein was polymerized in high molar ammonium sulfate and resulting filaments were pelleted with high-speed centrifugation and resuspended in 150 mM PBS. Under denaturing conditions the major band was only that of the full-length hFliC (b) Schematic diagram of in vivo immunization protocol used. The immunization period was five weeks, with four injections spaced a week apart. Priming injection at week zero was either administered IP or IN, and the three subsequent booster doses where all administered IN. c ELISA scans show serum IgA response in WT C57BL/6 J mice, assayed after the five-week immunization period. C57BL/6 J mice given polymeric hFliC IN throughout the entire immunization exhibited a strong serum IgA response, while all other mice showed no IgA titer. d ELISA scans for serum IgG response in WT C57BL/6 J, assayed after the five-week immunization period. C57BL/6 J mice given polymeric hFliC IP showed a stronger IgG response compared to mice given monomeric hFliC IP. e ELISA scans for serum IgM response in WT C57BL/6 J mice assayed after the five-week immunization period. Again, C57BL/6 J mice receiving polymeric hFliC IP showed strongest IgM response. f Serum IgG isotypes were assayed in C57BL/6 J mice, mice given polymeric hFliC IP showed a robust IgG1 response. All groups in immunization protocols used an n = 3-5 mice per group, and error bars represent the mean +/- SEM, and for statistical analyses, * - p < 0.05; ** - p < 0.005; *** - p < 0.0005. Values were reported as the fluorescence measured in 1:2000 serum dilutions, with background fluorescence values subtracted