Institute of Microbiology, Università Cattolica del Sacro Cuore - Fondazione Policlinico Universitario Gemelli, 00168 Rome, Italy.
Department of Biomedical Sciences, University of Sassari, Sassari 07100, Italy.
Pathog Dis. 2017 Nov 30;75(8). doi: 10.1093/femspd/ftx100.
Mycobacterium tuberculosis (Mtb) PE_PGRS33 is a surface-exposed protein that was shown to interact with Toll-like receptor 2 on host macrophages to induce inflammatory signals and promote entry in macrophages. In this study, we investigated PE_PGRS33 as a potential target of a humoral response aimed at hampering key processes in tuberculosis pathogenesis. PE_PGRS33 protein was successfully expressed and purified under native condition in Escherichia coli. The purified protein retained its native functional and biological properties, showing the ability to elicit proinflammatory signals in murine and human macrophages. Interestingly, a polyclonal antiserum raised against native PE_PGRS33 showed no cross-reactions with other mycobacterial proteins. The anti-PE_PGRS33 serum was also able to inhibit Mtb entry into macrophages, but it did not reduce entry of the MtbΔpe_pgrs33 strain. Addition of native recombinant PE_PGRS33 to the MtbΔpe_pgrs33 strain during infection restored the Mtb wild-type entry phenotype in macrophage. Moreover, the anti-PE_PGRS33 serum was able to neutralize the proinflammatory activity of PE_PGRS33 in vitro. Furthermore, mice immunized with native recombinant PE_PGRS33, but not with a DNA vaccine expressing PE_PGRS33, were able to restrict M. smegmatis in vivo. These results highlight the potential use of PE_PGRS33 as a target of a neutralizing humoral response against tuberculosis.
结核分枝杆菌（Mtb）PE_PGRS33 是一种表面暴露蛋白，已被证明与宿主巨噬细胞上的 Toll 样受体 2 相互作用，诱导炎症信号并促进巨噬细胞进入。在这项研究中，我们研究了 PE_PGRS33 作为一种针对体液反应的潜在靶点，旨在阻碍结核病发病机制中的关键过程。PE_PGRS33 蛋白在大肠杆菌中成功地在天然条件下表达和纯化。纯化的蛋白质保留了其天然的功能和生物学特性，显示出在鼠和人巨噬细胞中引发促炎信号的能力。有趣的是，针对天然 PE_PGRS33 产生的多克隆抗血清与其他分枝杆菌蛋白没有交叉反应。抗-PE_PGRS33 血清还能够抑制 Mtb 进入巨噬细胞，但不能减少 MtbΔpe_pgrs33 菌株的进入。在感染过程中向 MtbΔpe_pgrs33 菌株中添加天然重组 PE_PGRS33 可恢复 Mtb 野生型进入巨噬细胞的表型。此外，抗-PE_PGRS33 血清能够中和 PE_PGRS33 在体外的促炎活性。此外，用天然重组 PE_PGRS33 免疫的小鼠，但不是用表达 PE_PGRS33 的 DNA 疫苗免疫的小鼠，能够在体内限制 M. smegmatis。这些结果强调了将 PE_PGRS33 作为针对结核病的中和性体液反应的潜在靶点的用途。
