RESUMO
In endemic regions, Lyme disease is a potential health threat to dogs. Canine Lyme disease manifests with arthritis-induced lameness, anorexia, fever, lethargy, lymphadenopathy and, in some cases, fatal glomerulonephritis. A recent study revealed that the regional mean for the percentage of seropositive dogs in the north-east of the USA is 11.6%. The outer surface protein C (OspC) of Lyme disease spirochetes is an important virulence factor required for the establishment of infection in mammals. It is a leading candidate in human and canine Lyme disease vaccine development efforts. Over 30 distinct ospC phyletic types have been defined. It has been hypothesized that ospC genotype may influence mammalian host range. In this study, Ixodes scapularis ticks collected from the field in Rhode Island were assessed for infection with B. burgdorferi. Ticks were fed on purpose bred beagles to repletion and infection of the dogs was assessed through serology and PCR. Tissue biopsies (n=2) were collected from each dog 49 days post-tick infestation (dpi) and the ospC genotype of the infecting strains determined by direct PCR of DNA extracted from tissue or by PCR after cultivation of spirochetes from biopsy samples. The dominant ospC types associated with B. burgdorferi canine infections differed from those associated with human infection, indicating a relationship between ospC sequence and preferred host range. Knowledge of the most common ospC genotypes associated specifically with infection of dogs will facilitate the rational design of OspC-based canine Lyme disease vaccines and diagnostic assays.
Assuntos
Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Vacinas Bacterianas/imunologia , Borrelia burgdorferi/imunologia , Doenças do Cão/microbiologia , Doenças do Cão/parasitologia , Doença de Lyme/veterinária , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/genética , Anticorpos Antibacterianos/metabolismo , Antígenos de Bactérias/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Vacinas Bacterianas/genética , Vacinas Bacterianas/metabolismo , Borrelia burgdorferi/genética , Borrelia burgdorferi/isolamento & purificação , Cães , Genótipo , Ixodes/microbiologia , Ixodes/fisiologia , Doença de Lyme/microbiologia , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase/veterinária , Rhode Island , Análise de Sequência de DNA/veterinária , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterinária , Fatores de Virulência/sangue , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Treponema denticola is an anaerobic spirochete whose abundance in the subgingival crevice correlates with the development and severity of periodontal disease. The ability of T. denticola to survive and thrive in the hostile environment of the periodontal pocket is due, at least in part, to its ability to bind factor H (FH), a negative regulator of the alternative complement pathway. The FH binding protein of T. denticola has been identified as FhbB and its atomic structure has been determined. The interaction of FH with T. denticola is unique in that FH bound to the cell surface is cleaved by the T. denticola protease, dentilisin. It has been postulated that FH cleavage by T. denticola leads to immune dysregulation in periodontal pockets. In this study, we conduct a comparative assessment of the sequence, properties, structure and ligand binding kinetics of the FhbB proteins of strains 33521 and 35405. The biological outcome of the interaction of these strains with FH could differ significantly as 33521 lacks dentilisin activity. The data presented here offer insight into our understanding of the interactions of T. denticola with the host and its potential to influence disease progression.