Fig. 5

Humoral immune response in TI mouse model (6.5-TCR transgenic). a 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 were administered (IN). b ELISA scans of serum IgM in 6.5-TCR and B10.D2 over five-week immunization period. Only mice given polymeric hFliC IP in the priming dose showed a serum IgM response. All groups B10.D2 mice immunized showed a strong IgM response. Statistics were determined by unpaired Student’s t-test, p < 0.05 were considered statistically significant, and error bars represent the mean +/- SEM. c ELISA scans of serum IgG isotypes in 6.5-TCR, and B10.D2 mice. 6.5-TCR mice given polymeric hFliC IP in the priming dose exhibited a specific IgG3 response, meanwhile B10.D2 mice showed broader subclass distribution (more balanced between Th1 and Th2). All groups in immunization protocols used an n = 3-5 mice per group, and error bars represent the mean +/- SEM. Values were reported as the fluorescence measured in 1:2000 serum dilution in the case of IgM and IgG isotypes for B10.D2 immunized mice, and values were reported as the fluorescence measured in 1:500 serum dilution for IgG isotype for 6.5-TCR immunized mice, with background fluorescence values subtracted, and for statistical analyses, * - p < 0.05; ** - p < 0.005; *** - p < 0.0005. Arrows show that there was a specifically increased IgG3 response in 6.5-TCR mice to IP hFliC filament while IgG2b responses were higher to monomer, while by contrast, in B10.D2 mice IgG1 and IgG2a responses were strong to both IP hFliC filament and monomer