结核分枝杆菌Rv2626c诱导的细胞免疫应答特性

Characterization of the cellular immune response induced by Mycobacterium tuberculosis Rv2626c

摘要:

全球有近1/4的人感染结核分枝杆菌（Mycobacterium tuberculosis，M.tb）并长期处于潜伏感染状态。Rv2626c是结核分枝杆菌受DosR调控的重要潜伏感染相关蛋白。本研究对Rv2626c蛋白进行了原核表达和纯化，并以RAW264.7细胞和小鼠为感染模型，对其免疫生物学特性进行了分析。SDS-PAGE及Western blotting鉴定结果表明，Rv2626c-His融合蛋白主要以可溶形式表达，能与兔抗H37Rv多抗血清发生特异性免疫反应。此外，本研究发现Rv2626c蛋白能结合到巨噬细胞RAW 264.7表面并上调细胞NO的生成；显著诱导促炎细胞因子IFN-γ、TNF-α、IL-6和MCP-1的产生；并能诱导小鼠产生更强的Th1免疫应答。上述研究有利于揭示结核分枝杆菌的致病机制，为新型结核病疫苗的研制奠定了理论基础。

关键词:结核分枝杆菌;Rv2626c;巨噬细胞;细胞因子;Th1型应答

Abstract:

Nearly a quarter of the world's population is infected with Mycobacterium tuberculosis and remains long-term asymptomatic infection. Rv2626c is a latent infection-related protein regulated by DosR of M. tuberculosis. In this study, the Rv2626c protein was prokaryotically expressed and purified, and its immunobiological characteristics were analyzed using RAW264.7 cells and mice as infection models. SDS-PAGE and Western blotting analysis showed that the Rv2626c-His fusion protein was mainly expressed in soluble form and specifically reacted with the rabbit anti-H37RV polyclonal serum. In addition, we found that the Rv2626c protein bound to the surface of RAW264.7 macrophages and up-regulated the production of NO. Moreover, the Rv2626c protein significantly induced the production of pro-inflammatory cytokines IFN-γ, TNF-α, IL-6 and MCP-1, and induced strong Th1-tendency immune response. These results may help to reveal the pathogenic mechanism of M. tuberculosis and facilitate the development of new tuberculosis vaccine.

Key words:Mycobacterium tuberculosis;Rv2626c;macrophage cell;cytokines;Th1 type immunity