Immunoproteomic analysis of Borrelia miyamotoi for the identification of serodiagnostic antigens

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.