Attachment of Borrelia burgdorferi within Ixodes scapularis mediated by outer surface protein A
Utpal Pal, … , Yves Lobet, Erol Fikrig
Utpal Pal, … , Yves Lobet, Erol Fikrig
Published August 15, 2000
Citation Information: J Clin Invest. 2000;106(4):561-569. https://doi.org/10.1172/JCI9427.
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Article

Attachment of Borrelia burgdorferi within Ixodes scapularis mediated by outer surface protein A

Abstract

Borrelia burgdorferi outer surface protein (Osp) A has been used as a Lyme disease vaccine that blocks transmission: OspA antibodies of immune hosts enter ticks during blood feeding and destroy spirochetes before transmission to the host can occur. B. burgdorferi produce OspA in the gut of unfed Ixodes scapularis ticks, and many spirochetes repress OspA production during the feeding process. This preferential expression suggests that OspA may have an important function in the vector. Here we show that OspA mediates spirochete attachment to the tick gut by binding to an I. scapularis protein. The binding domains reside in the central region and COOH-terminus of OspA. OspA also binds to itself, suggesting that spirochete-spirochete interactions may further facilitate adherence in the gut. OspA-mediated attachment in the tick provides a possible mechanism for how stage-specific protein expression can contribute to pathogenesis during the B. burgdorferi natural cycle.

Authors

Utpal Pal, Aravinda M. de Silva, Ruth R. Montgomery, Durland Fish, Juan Anguita, John F. Anderson, Yves Lobet, Erol Fikrig

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Binding of OspAs with mutations within amino acids 85–103 or 229–247 to ...
Binding of OspAs with mutations within amino acids 85–103 or 229–247 to TGE. Site-directed mutagenesis was performed to generate OspAs, designated M1–M6 with substitution in amino acids that are conserved between B. burgdorferi species within region 85–103 and 229–247 (Figure 6d). M1–M6 contain the following amino acid replacements: M1 (KVK85–87 to ΔEVE), M2 (DL93–94 to ΔAR), M3 (EVFK100–103 to ΔAVFA), M4 (K231 to ΔA), M5 (VF236–237 to ΔGS), and M6 (TIT242–244 to ΔANA). Binding of OspA and M1–M6 to TGE is depicted. B represents binding of OspA to BSA (control). M1–M6 showed a similar degree of binding to BSA (data not shown). Bars represent the mean ± SD from four experiments. AP < 0.001.