Document Type


Publication Date



This article is the author's final published version in Proceedings of the National Academy of Sciences, Volume 119, Issue 42, Oct. 2022, Article number e2205460119.

The online version is available at Copyright © 2022 the Author(s). Published by PNAS.


Relapsing fever due to Borrelia hermsiiis characterized by recurrent bacteremia episodes. However, infection of B. hermsii, if not treated early, can spread to various organs including the central nervous system (CNS). CNS disease manifestations are commonly referred to as relapsing fever neuroborreliosis (RFNB). In the mouse model of B. hermsiiinfection, we have previously shown that the development of RFNB requires innate immune cells as well as T cells. Here, we found that prior to the onset of RFNB, an increase in the systemic proinflammatory cytokine response followed by sustained levels of IP-10 concurrent with the CNS disease phase. RNA sequencing analysis of the spinal cord tissue during the disease phase revealed an association of the interleukin (IL)-17 signaling pathway in RFNB. To test a possible role for IL-17 inRFNB, we compared B. hermsii infection in wild-type and IL-17A2/2mice. Although the onset of bacteremia and protective anti-B. hermsii antibody responses occurred similarly, the blood-brain barrier permeability, proinflammatory cytokine levels, immune cell infiltration in the spinal cord, and RFNB manifestations were significantly diminished in IL-17A2/2mice compared to wild-type mice. Treatment of B. hermsii-infected wild-type mice with anti-IL-17A antibody ameliorated the severity of spinal cord inflammation, microglial cell activation, and RFNB. These data suggest that the IL-17signaling pathway plays a major role in the pathogenesis of RFNB, and IL-17A blockade may be a therapeutic modality for controlling neuroborreliosis.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

PubMed ID