Immunoproteomic analysis of Borrelia miyamotoi for the identification of serodiagnostic antigens

Emma K Harris,Maria Angela De Mello Marques,John T Belisle,Gary P Wormser,Marisa R Harton,Robert D Gilmore,Nicole Breuner,Claudia R Molins

doi:10.1038/s41598-019-53248-5

Abstract

The tick-borne spirochete, Borrelia miyamotoi, is an emerging pathogen of public health significance. Current B. miyamotoi serodiagnostic testing depends on reactivity against GlpQ which is not highly sensitive on acute phase serum samples. Additionally, anti-B. miyamotoi antibodies can cross-react with C6 antigen testing for B. burgdorferi, the causative agent of Lyme disease, underscoring the need for improved serological assays that produce accurate diagnostic results. We performed an immunoproteomics analysis of B. miyamotoi proteins to identify novel serodiagnostic antigens. Sera from mice infected with B. miyamotoi by subcutaneous inoculation or tick bite were collected for immunoblotting against B. miyamotoi membrane-associated proteins separated by 2-dimensional electrophoresis (2DE). In total, 88 proteins in 40 2DE immunoreactive spots were identified via mass spectrometry. Multiple variable large proteins (Vlps) and a putative lipoprotein were among those identified and analyzed. Reactivity of anti-B. miyamotoi sera against recombinant Vlps and the putative lipoprotein confirmed their immunogenicity. Mouse anti-B. burgdorferi serum was cross-reactive to all recombinant Vlps, but not against the putative lipoprotein by IgG. Furthermore, antibodies against the recombinant putative lipoprotein were present in serum from a B. miyamotoi-infected human patient, but not a Lyme disease patient. Results presented here provide a comprehensive profile of B. miyamotoi antigens that induce the host immune response and identify a putative lipoprotein as a potentially specific antigen for B. miyamotoi serodetection.

Highlights

The tick-borne spirochete, Borrelia miyamotoi, is an emerging pathogen of public health significance
Antibodies produced against variable major proteins (Vmps) may be susceptible to cross-reactivity with the orthologous B. burgdorferi protein Vmp-like sequence expressed (VlsE), which comprises the sensitive C6 antigen used for Lyme disease (LD) testing[16,17]
IgM immunoblotting with serum collected at 8 dpi derived from tick bite inoculation reacted with 17 immunogenic spots representing 47 protein identities (Fig. 2b; Table 1)

Summary

Introduction

The tick-borne spirochete, Borrelia miyamotoi, is an emerging pathogen of public health significance. Antibodies against the recombinant putative lipoprotein were present in serum from a B. miyamotoi-infected human patient, but not a Lyme disease patient. We hypothesized that a comprehensive immunoproteomic analysis of the host antibody response against B. miyamotoi infection would reveal unique antigens to augment GlpQ and Vmps for improved serodiagnostic detection of BMD. Mass spectrometry was used to identify putative serum-reactive proteins leading to the identification of a novel lipoprotein antigen with the potential to differentiate BMD from LD. These analyses demonstrate considerable variability in the antibody response between mice infected via subcutaneous inoculation and tick bite, as well as across the course of infection

Methods

Results

Conclusion