Prokaryotic expression and immune function of Mycobacterium tuberculosis Rv3133 c gene / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To construct a plasmid for expression Mycobacterium tuberculosis ( Mtb) Rv3133c and to evaluate the immunogenicity of Rv3133c through population and mice experiments. Methods:The recombinant expression plasmid pPROEX-Rv3133c was constructed. The transformed E. coli BL21 (DE3) carrying expression plasmid was induced by IPTG to express the recombinant Rv3133c (rRv3133c). Western blot was used to identify the expressed protein. Whole-blood IFN-γ release assay (WBIA) was preformed to assess the immunogenicity of rRv3133c in Mtb-infected population. Antigen-specific antibodies in serum, Th1 type cytokines in splenocytes, functional T cell subset responses in splenocytes and the expression of cytokines at mRNA level in lung tissues were detected after immunizing mice subcutaneously with rRv3133c and adjuvant DC. Results:The rRv3133c was constructed and expressed successfully. Stimulation with rRv3133c promoted the production of IFN-γ in Mtb-infected population, especially in patients with latent tuberculosis infections. After immunizing mice with rRv3133c+ DC, the levels of IFN-γ, TNF-α and IL-2, the number of IFN-γ + TNF-α + CD4 + T cells in spleen and the expression of antigen-specific IFN-γ, TNF-α and iNOS at mRNA level in lung tissues were higher than those in BCG-immunized mice, but lower than those in BCG+ rRv3133c+ DC group. The serum IgG2a/IgG1 ratios in the rRv3133c+ DC group and the BCG+ rRv3133c+ DC group were greater than 1, and significantly higher than that of the BCG group. Conclusions:The rRv3133c had good immunogenicity and could induce strong Th1 immune response, suggesting that it was a potential candidate antigen for subunit vaccine against tuberculosis.