Immunogenicity of mannan derived from Mycobacterium bovis as a promising adjuvant in vaccine BCG.

Background and objectives: Lipoarabinomannan is one of the components of the significant structural cell surfaces of mycobacteria and serves as an immunostimulatory factor. TNF-α and IL-12 are two examples of the anti-bacterial inflammatory cytokines that are activated and induced during infection.

Materials and methods: In this study, mannan was extracted and processed, and then Bulb/c female mice were used in three groups, one group was given BCG vaccine, the other group was given BCG vaccine with mannan adjuvant, and a non-injected group was used as a control group. Inflammatory factors interleukin-12, TNF-α, IgG and IgM were measured in mouse serum.

Results: The levels of the inflammatory factors interleukin-12 and TNF-α in the serum isolated from mice receiving the BCG vaccine with mannan adjuvant showed a significant difference compared to the group that received only the BCG vaccine and the control group [IL-12] and , with P≤0.05.The examination of the level of IgG immune factors in these three groups revealed a significant difference. The group that received the BCG vaccine with mannan adjuvant showed a marked contrast compared to the group that received only the BCG vaccine and the control group, with P≤0.05. The level of IgM was higher in the group that received the BCG vaccine alone compared to the adjuvant vaccine group and the control group, with P≤0.05.

Conclusion: Our results indicated that mice receiving the BCG vaccine with mannan adjuvant had significantly higher serum levels of IL-12, TNF-α, and IgG than the group receiving BCG alone.