Correlations Between BCG Vaccination On Specific Antibodies In Serum And The Expression Of Immunity-related Genes In Spleen From Mice

Objective: The tuberculosis(TB) pandemic continues to rampage despite widespread use of the BCG(Bacillus Calmette–Gue ′rin) vaccine. BCG is the only licensed TB vaccine. However, a number of epidemiological studies and controlled clinical trials have shown that the BCG vaccine has several limitations. As the development of new vaccines more effective and safe than the BCG vaccine is considered a priority, people should understand the immune mechanism which induced by BCG in vivo more. The experiments were carried out to study the influence of BCG vaccination on specific antibodies in serum and the expression of immunity-related cytokines and the distribution of immunity-related reporters in spleen from mice.Method: The peripheral blood and spleen from C57BL/6 mice vaccinated with BCG were collected at different time points. Then the specific antibodies in serum were detected by indirect ELISA, and the expression of immunity-related cytokines(IL-2、IL-10、IL-4、IL-12、IFN-γ) in spleen were detected by real-time quantitative PCR. At last, the distribution of immunity-related reporters in spleen were detected by indirect IHC fluorescence.Result: After the BCG vaccination, the value of specific antibodies was successfully detected in a significant increase trend. These date suggest that organism would generate humoral immunity responses in the stage of BCG vaccination. Then it were successfully detected that the expression of immunity-related cytokines IL-2、IL-10、IL-4、IL-12、IFN-γ change in different degrees. The expression of Th1 type cytokine IL-2, IFN-γ were increased, the difference was significant(p<0.05)while the expression of Th2 type cytokine IL-4 was reduced(p<0.05). In the early stages of BCG vaccination, the expression of TLR2 receptor in the spleen was successfully detected in a significant increase trend, but reducing to normal levels in the late stages of BCG vaccination. In the medium-term stages of BCG vaccination, the expression of TLR9 receptor was successfully detected in a significant increase trend, but reducing to normal levels in the late stages of BCG vaccination.Conclusion: The study found that the specific antibodies in serum, immunity-related cytokines and the immunity-related reporters were connected to each other during the stage of BCG vaccination. Especially in the late stage of vaccination,Th1 type cytokines are positively correlated with humoral immunity responses, but some Th2 type cytokine is negatively correlated with it.