Figure 6.

Th1-type biased immune responses in immunized mice at the ninth and 18th week after immunization (n = 6). Mice were immunized with pCMFO, pCMFO/DDA, and pCMFO/DMT, respectively. Bacillus Calmette–Guérin (BCG) was used as a positive control, and PBS, dimethyldioctadecylammonium (DDA), and DMT alone were performed as negative controls. (A) IgG, IgG1, and IgG2a antibodies against CMFO in sera were detected by ELISA. Results are shown as mean (±SEM) log10 endpoint titer. (B) The ratio of IgG2a/IgG1 in the different vaccinated mice. (C) The levels of PPD or CMFO-specific IFN-γ secreted by splenocytes. 5 × 10⁶ of splenocytes from each mouse in different groups were re-stimulated with 10 µg/mL of CMFO or PPD for 72 h at 37°C, 5% CO₂. The supernatants were collected and ELISA was used to detect the concentration of IFN-γ. Results are expressed as mean ± SD (pg/mL). A p-value for the comparison between different groups is shown above the bars in panels. *p < 0.05, 9 vs. 18 weeks of the same vaccinated mice.