Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Infect Immun. 2011 Apr;79(4):1451-7. doi: 10.1128/IAI.01274-10. Epub 2011 Jan 31.
Borrelia burgdorferi, the Lyme disease spirochete, binds the host complement inhibitors factor H (FH) and FH-like protein 1 (FHL-1). Binding of FH/FHL-1 by the B. burgdorferi proteins CspA and the OspE-related proteins is thought to enhance resistance to serum-mediated killing. While previous reports have shown that CspA confers serum resistance in B. burgdorferi, it is unclear whether the OspE-related proteins are relevant in B. burgdorferi serum resistance when OspE is expressed on the borrelial surface. To assess the role of the OspE-related proteins, we overexpressed them in a serum-sensitive CspA mutant strain. OspE overexpression enhanced serum resistance of the CspA-deficient organisms. Furthermore, FH was more efficiently bound to the B. burgdorferi surface when OspE was overexpressed. Deposition of complement components C3 and C5b-9 (the membrane attack complex), however, was reduced on the surface of the OspE-overexpressing strain compared to that on the CspA mutant strain. These data demonstrate that OspE proteins expressed on the surface of B. burgdorferi bind FH and protect the organism from complement deposition and subsequent serum-mediated destruction.
伯氏疏螺旋体，莱姆病螺旋体，可结合宿主补体抑制剂因子 H（FH）和 FH 样蛋白 1（FHL-1）。据认为，B. burgdorferi 蛋白 CspA 和 OspE 相关蛋白与 FH/FHL-1 的结合增强了对血清介导杀伤的抵抗力。尽管先前的报告表明 CspA 可赋予 B. burgdorferi 血清抗性，但当 OspE 表达于螺旋体表面时，OspE 相关蛋白是否与 B. burgdorferi 血清抗性相关尚不清楚。为了评估 OspE 相关蛋白的作用，我们在血清敏感的 CspA 突变株中过表达了它们。OspE 的过表达增强了 CspA 缺陷生物的血清抗性。此外，当 OspE 过表达时，FH 更有效地结合到 B. burgdorferi 表面。然而，与 CspA 突变株相比，OspE 过表达株表面补体成分 C3 和 C5b-9（膜攻击复合物）的沉积减少。这些数据表明，表达在 B. burgdorferi 表面的 OspE 蛋白结合 FH，保护生物体免受补体沉积和随后的血清介导的破坏。
