Homogeneity of Borrelia japonica and heterogeneity of Borrelia afzelii and 'Borrelia tanukii' isolated in Japan, determined from ospC gene sequences

Borrelia afzelii, B. japonica, and `B. tanukii' isolated from various sources and geographical origins in Japan were characterized by restriction fragment length polymorphism (RFLP) analysis and sequencing analysis of the outer surface protein C (OspC) amplicon. B. afzelii and `B. tanukii' generated variable RFLP patterns and differences in ospC gene sequence were confirmed. In contrast, 26 isolates of B. japonica generated one OspC RFLP type, and sequence similarity between B. japonica ranged from 96.4 to 99.7%. These finding suggests that B. japonica is unique in comparison with other members of B. burgdorferi sensu lato species with respect to homogeneity of the ospC gene.     

Borrelia burgdorferi outer surface protein C (OspC) binds complement component C4b and confers bloodstream survival

Borrelia burgdorferi (Bb) is the causative agent of Lyme disease in the United States, a disease that can result in carditis, and chronic and debilitating arthritis and/or neurologic symptoms if left untreated. Bb survives in the midgut of the Ixodes scapularis tick, or within tissues of immunocompetent hosts. In the early stages of infection, the bacteria are present in the bloodstream where they must resist clearance by the innate immune system of the host. We have found a novel role for outer surface protein C (OspC) from B. burgdorferi and B. garinii in interactions with the complement component C4b and bloodstream survival in vivo. Our data show that OspC inhibits the classical and lectin complement pathways and competes with complement protein C2 for C4b binding. Resistance to complement is important for maintenance of the lifecycle of Bb, enabling survival of the pathogen within the host as well as in the midgut of a feeding tick when ospC expression is induced.     

Expression and sequence of outer surface protein C among North American isolates of Borrelia burgdorferi

Abstract The expression of outer surface protein C (OspC) was determined for North American Borrelia burgdorferi isolates HB19, DN127c19-2, 25015 and both low and high culture passage B31. A monoclonal antibody detected the presence of OspC protein in only two isolates, while polyclonal antiserum identified this protein in all five isolates. The ospC gene was cloned and sequenced for isolates HB19, DN127c19-2 and 25015, and compared with the published ospC sequences of other Lyme disease spirochetes. Bothe the nucleotide and amino acid sequences were found to vary as much among isolates from the same geographic area as between isolates of different species.     

DNA‐based identification and OspC serotyping in cultures of Borrelia burgdorferi s.l. isolated from ticks collected in the Moravia (Czech Republic)

Two different genetic loci, flaB and ospC, were employed to assign genospecies and OspC phylogenetic type to 18 strains isolated from ticks collected in Pisárky, a suburban park in the city of Brno, Czech Republic. The RFLP analysis revealed three different genospecies (B. afzelii, B. garinii, and B. valaisiana). Three samples from the collection contained more than one genospecies. In the other 15 strains, nucleotide sequences of flaB and ospC were determined. The following phylogenetic analysis assigned 12 isolates to genospecies B. garinii and three to B. afzelii. These isolates were further subdivided into seven distinct ospC groups. The most related OspC types were G2, G4, and G5 (B. garinii) and A3 and A8 (B. afzelii).     

Epitope mapping of Borrelia burgdorferi OspC protein in homodimeric fold

In current work, we used recombinant OspC protein derived from B. afzelii strain BRZ31 in the native homodimeric fold for mice immunization and following selection process to produce three mouse monoclonal antibodies able to bind to variable parts of up to five different OspC proteins. Applying the combination of mass spectrometry assisted epitope mapping and affinity based theoretical prediction we have localized regions responsible for antigen‐antibody interactions and approximate epitopes' amino acid composition. Two mAbs (3F4 and 2A9) binds to linear epitopes located in previously described immunogenic regions in the exposed part of OspC protein. The third mAb (2D1) recognises highly conserved discontinuous epitope close to the ligand binding domain 1.     

Characterization of a unique borreliacidal epitope on the outer surface protein C of Borrelia burgdorferi

The outer surface protein C (OspC) of the Lyme disease agent, Borrelia burgdorferi, is an immunoprotective antigen in laboratory models of infection. However, to understand its protective effects, it is important to identify the key epitopes of this protein. We produced a borreliacidal anti-OspC monoclonal antibody specific to the B31 strain and identified its binding site. The specificity of MAb 16.22 was determined by Western blot reactivity using OspC derived from different Borrelia isolates which had varying amino acid sequences. Comparison of the OspC sequences and binding data suggested that MAb 16.22 binds to amino acids 133-147 of the OspC protein. To test this hypothesis, we synthesized a 15-amino acid peptide containing the target sequence and, using competition enzyme-linked immunosorbent assay (ELISA), we found that this peptide included the epitope of MAb 16.22. In addition, we determined that MAb 16.22 is able to kill of B. burgdorferi in a complement-independent fashion.     

A family of conserved bacterial virulence factors dampens interferon responses by blocking calcium signaling

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Relationship between infectivity and OspC expression in Lyme disease Borrelia

Abstract Borrelia burgdorferi sensu stricto strain 297 and B. garinii strains HP1 and 12–92 were serially subcultured for 36–50 passages in vitro for 1 year. All low-passage strains showed abundant expression of outer surface protein C (OspC) in the 22–23-kDa range, but the high-passage strains lost or showed reduced expression of OspC in comparison with the low-passage strains. The low-passage strains efficiently infected outbred ddY mice when inoculated into the hind footpad or peritoneal cavity. In contrast, the incidence of infection with the high-passage strains was low. Isolates from the bladders of mice inoculated with the high-passage strains expressed large amounts of OspC in comparison with those originally inoculated. These results indicate that OspC expression is related to the infectivity of Lyme disease borreliae.     

Evidence for frequent OspC gene transfer between Borrelia valaisiana sp. nov. and other Lyme disease spirochetes

IMP-1 metallo-beta-lactamase is a transferable carbapenem-hydrolyzing enzyme found in some clinical isolates of Pseudomonas aeruginosa, Serratia marcescens and Klebsiella pneumoniae. Bacteria that express IMP-1 show significantly reduced sensitivity to carbapenems and other beta-lactam antibiotics. A series of thioester derivatives has been shown to competitively inhibit purified IMP-1. As substrates for IMP-1, the thioesters yielded thiol hydrolysis products which themselves were reversible competitive inhibitors. The thioesters also increased sensitivity to the carbapenem L-742,728 in an IMP-1-producing laboratory stain of Escherichia coli, but will need further modification to improve their activity in less permeable organisms such as Pseudomonas and Serratia. Nonetheless, the thioester IMP-1 inhibitors offer an encouraging start to overcoming metallo-beta-lactamase-mediated resistance in bacteria.