B-cell epitopes in GroEL of Francisella tularensis.
B-cell epitopes in GroEL of Francisella tularensis.
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DOI：
10.1371/journal.pone.0099847
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Sharon J
中科院分区：
文献类型：
--
作者：
Lu Z;Rynkiewicz MJ;Madico G;Li S;Yang CY;Perkins HM;Sompuram SR;Kodela V;Liu T;Morris T;Wang D;Roche MI;Seaton BA;Sharon J
伴侣蛋白GroEL，也称为热休克蛋白60（Hsp 60），是人和小鼠对兼性细胞内细菌土拉热弗朗西斯菌（Ft）（土拉菌病的病原体）的抗体应答中的主要抗原。除了其假定的细胞质位置之外，据报道FtGroEL是细菌表面的潜在组分并从细菌中释放。在目前的研究中，13个IgG 2a和一个IgG 3小鼠单克隆抗体（mAb）的FtGroEL特异性被分为11个独特的组的基础上共享的VH-VL种系基因，和七个交叉阻断谱揭示至少三个非重叠的表位区域的竞争ELISA。在使用高致病性Ft A型菌株SchuS 4的呼吸道土拉菌病小鼠模型中，阻断彼此结合至FtGroEL中相同的两个点突变并且对FtGroEL中相同的两个点突变敏感的Ab 64和N200 IgG 2a mAb降低了细菌负荷，表明它们靶向保护性GroEL B细胞表位。Ab 64和N200表位以及具有不同交叉阻断谱的其他三种mAb Ab 53、N3和N30的表位通过氢/氘交换质谱法（DXMS）作图，并在FtGroEL的同源性模型上可视化。该模型进一步得到了实验验证的计算对接Ab 64和Ab 53 Fab的X射线晶体结构的支持。Ab 64和N200 mAb的结构分析和DXMS谱表明，它们的保护作用可能是由于诱导或稳定FtGroEL中的构象变化。
The chaperonin protein GroEL, also known as heat shock protein 60 (Hsp60), is a prominent antigen in the human and mouse antibody response to the facultative intracellular bacterium Francisella tularensis (Ft), the causative agent of tularemia. In addition to its presumed cytoplasmic location, FtGroEL has been reported to be a potential component of the bacterial surface and to be released from the bacteria. In the current study, 13 IgG2a and one IgG3 mouse monoclonal antibodies (mAbs) specific for FtGroEL were classified into eleven unique groups based on shared VH-VL germline genes, and seven crossblocking profiles revealing at least three non-overlapping epitope areas in competition ELISA. In a mouse model of respiratory tularemia with the highly pathogenic Ft type A strain SchuS4, the Ab64 and N200 IgG2a mAbs, which block each other’s binding to and are sensitive to the same two point mutations in FtGroEL, reduced bacterial burden indicating that they target protective GroEL B-cell epitopes. The Ab64 and N200 epitopes, as well as those of three other mAbs with different crossblocking profiles, Ab53, N3, and N30, were mapped by hydrogen/deuterium exchange–mass spectrometry (DXMS) and visualized on a homology model of FtGroEL. This model was further supported by its experimentally-validated computational docking to the X-ray crystal structures of Ab64 and Ab53 Fabs. The structural analysis and DXMS profiles of the Ab64 and N200 mAbs suggest that their protective effects may be due to induction or stabilization of a conformational change in FtGroEL.
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影响因子：
64.5
作者：
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