Immunological and molecular analyses of the Borrelia hermsii factor H and factor H-like protein 1 binding protein, FhbA:: Demonstration of its utility as a diagnostic marker and epidemiological tool for tick-borne relapsing fever
Immunological and molecular analyses of the Borrelia hermsii factor H and factor H-like protein 1 binding protein, FhbA:: Demonstration of its utility as a diagnostic marker and epidemiological tool for tick-borne relapsing fever
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DOI：
10.1128/iai.00377-06
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发表时间：
2006-08-01
影响因子：
3.1
通讯作者：
Marconi, Richard T.
中科院分区：
文献类型：
--
作者：
Hovis, Kelley M.;Schriefer, Martin E.;Marconi, Richard T.
赫氏疏螺旋体（回归热的病原体）已被证明可产生 H 因子 (FH) 和 FH 样蛋白 1 (FHL-1) 结合蛋白。该结合蛋白被命名为 FhbA。为了确定 FH/FHL-1 结合是否在赫氏芽孢杆菌分离株中广泛存在，对一组不同菌株的 FH/FHL-1 结合表型和 FhbA 产生进行了测试。大多数分离株 (23/24) 产生 FhbA 并结合 FH/FHL-1。通过 DNA 序列分析来分析分离株之间 FhbA 的潜在变异。描述了两种遗传上不同的 FhbA 类型，命名为 fhbA1 和 fhbA2，并生成了类型特异性 PCR 引物以实现快速分化。脉冲场凝胶电泳和杂交分析表明，所有拥有该基因的分离株都在 200 kb 线性质粒 (Ip200) 上携带该基因，而缺乏该基因的分离株则缺乏 Ip200，而是携带 Ip170。为了确定 FhbA 在感染过程中是否具有抗原性并评估反应的特异性，用受感染小鼠和人类的血清筛选重组 FhbA1 (rFhbA1) 和 rFhbA2。研究发现 FhbA 具有表达性和抗原性，可引发潜在的类型特异性 FhbA 反应。为了定位 FhbA1 和 FhbA2 的表位，生成截短片段并用感染血清进行筛选。表位被确定为构象定义的。总的来说，这些分析表明 FH/FHL-1 结合是赫氏芽孢杆菌的一种广泛的毒力机制，并提供了对 FhbA 遗传和抗原结构的深入了解。这些数据对于了解北美回归热的流行病学也具有潜在的意义，并且可以应用于未来物种特异性诊断工具的开发。
It has been demonstrated that Borrelia hermsii, a causative agent of relapsing fever, produces a factor H (FH) and FH-like protein 1 (FHL-1) binding protein. The binding protein has been designated FhbA. To determine if FH/FHL-1 binding is widespread among B. hermsii isolates, a diverse panel of strains was tested for the FH/FHL-1 binding phenotype and FhbA production. Most isolates (23/24) produced FhbA and bound FH/FHL-1. Potential variation in FhbA among isolates was analyzed by DNA sequence analyses. Two genetically distinct FhbA types, designated fhbA1 and fhbA2, were delineated, and type-specific PCR primers were generated to allow for rapid differentiation. Pulsed-field gel electrophoresis and hybridization analyses demonstrated that all isolates that possess the gene carry it on a 200-kb linear plasmid (Ip200), whereas isolates that lack the gene lack Ip200 and instead carry an Ip170. To determine if FhbA is antigenic during infection and to assess the specificity of the response, recombinant FhbA1 (rFhbA1) and rFhbA2 were screened with serum from infected mice and humans. FhbA was found to be expressed and antigenic and to elicit a potentially type-specific FhbA response. To localize the epitopes of FhbA1 and FhbA2, truncations were generated and screened with infection serum. The epitopes were determined to be conformationally defined. Collectively, these analyses indicate that FH/FHL-1 binding is a widespread virulence mechanism for B. hermsii and provide insight into the genetic and antigenic structure of FhbA. The data also have potential implications for understanding the epidemiology of relapsing fever in North America and can be applied to the future development of species-specific diagnostic tools.