Borrelia burgdorferi chemotaxis toward tick protein Salp12 contributes to acquisition

• Authors: Kristen E. Murfin, Yale University School of Medicine; Ruby Kleinbard, Emory University; Merve Aydin, Yale University School of Medicine; Samuel A. Salazar, Yale University School of Medicine; Erol Fikrig, Yale University School of Medicine
• Journal Title: Ticks and Tick-Borne Diseases
• Volume: Volume 10, Number 5
• Publisher: Elsevier | 2019-08-01, Pages 1124-1134
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.ttbdis.2019.06.002
• Subjects: Health Sciences, Epidemiology; Health Sciences, Medicine and Surgery
• Keywords: Borrelia burgdorferi sensu stricto; chemotaxis; acquisition; Ixodes scapularis; tick; Lyme disease

Abstract

Lyme disease is a common tick-borne infection caused by the spirochete Borrelia burgdorferi sensu stricto (s.s.). B. burgdorferi s.s. may utilize chemotaxis, the directional migration towards or away from a chemical stimulus, for transmission, acquisition, and infection. However, the specific signals recognized by the spirochete for these events have not been defined. In this study, we identify an Ixodes scapularis salivary gland protein, Salp12, that is a chemoattractant for the spirochete. We demonstrate that Salp12 is expressed in the I. scapularis salivary glands and midgut and expression is not impacted by B. burgdorferi s.s. infection. Knockdown of Salp12 in the salivary glands or passive immunization against Salp12 reduces acquisition of the spirochete by ticks but acquisition is not completely prevented. Knockdown does not impact transmission of B. burgdorferi s.s. This work suggests a new role for chemotaxis in acquisition of the spirochete and suggests that recognition of Salp12 contributes to this phenomenon.