Analysis of the antigenic determinants of the OspC protein of the Lyme disease spirochetes: Evidence that the C10 motif is not immunodominant or required to elicit bactericidal antibody responses. Issue 17 (17th April 2019)

• Record Type: Journal Article
• Authors: Izac, Jerilyn R.; Camire, Andrew C.; Earnhart, Christopher G.; Embers, Monica E.; Funk, Rebecca A.; Breitschwerdt, Edward B.; Marconi, Richard T.
• Is Part Of: Vaccine. Volume 37:Issue 17(2019)
• Page Start: 2401
• Page End: 2407
• Publication Date: 2019-04-17
• Subjects: Borreliella -- Lyme disease -- OspC -- Lyme disease vaccine -- Borrelia; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2019.02.007
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: OspC of the Lyme disease spirochetes triggers highly specific IgG responses in a diverse mammals. IgG responses to OspC are not elicited by conserved regions of the protein. The C7/C10 motif does not play a central role in triggering IgG responses. The C7/C10 motif is not required for induction of bactericidal antibody. Abstract: As Ixodes ticks spread to new regions, the incidence of Lyme disease (LD) in companion animals and humans will increase. Preventive strategies for LD in canines center on vaccination and tick control (acaricides). Both subunit and bacterin based LD veterinary vaccines are available. Outer surface protein C (OspC), a potent immunogen and dominant early antigen, has been demonstrated to elicit protective antibody (Ab) responses. However, a single OspC protein elicits a relatively narrow range of protection. There are conflicting reports as to whether the immunodominant epitopes of OspC reside within variable or conserved domains. A detailed understanding of the antigenic determinants of OspC is essential for understanding immune responses to this essential virulence factor and vaccinogen. Here, we investigate the contribution of the conserved C-terminal C10 motif in OspC triggered Ab responses. Using a panel of diverse recombinant full length OspC proteins and their corresponding C10 deletion variants (OspCΔC10), we demonstrate that the C10 motif does not significantly contribute to immunization or infection induced Ab responses in rabbits, rats, canines, horses and non-human primates. Furthermore, the C10 motif is not required to trigger potent bactericidal Ab responses. This study provides insight into the antigenic structure of OspC. The results enhance our understanding of immune responses that develop during infection or upon vaccination and have implications for interpretation of LD diagnostic assays that employ OspC.