ANAIS 2014

DETECTION OF GENOTYPE-SPECIFIC EHRLICHIA CANIS ANTIBODIES IN BRAZIL USING TRP36 PEPTIDE ELISA Autor(es): Daniel Moura de Aguiar, Xiaofeng Zhang, Jere Williams McBride

DETECTION OF GENOTYPE-SPECIFIC EHRLICHIA CANIS ANTIBODIES IN BRAZIL USING TRP36 PEPTIDE ELISA

» Á�rea de pesquisa: DOENÇAS VETORIAIS

» Instituição: Universidade Federal de Mato Grosso

» Agência de fomento e patrocinadores: CNPQ

We recently characterized a novel genotype of Ehrlichia canis based on the tandem repeat (TR) sequence of the TRP36 gene in Brazil. The TR amino acid sequence of the Brazilian genotype (ASVVPEAE) was divergent to the previously described US genotype (TEDSVSAPA). In this study, we developed an ELISA with TRP36 TR synthetic peptides from both Brazilian and US E. canis TRP36 genotypes to detect and distinguish infections caused by these genotypes.Sera from 12 Brazilian dogs naturally infected with E. canis, sera from dogs experimentally infected E. canis (Jake strain) and E. chaffeensis (Arkansas strain) and six seronegative E. canis dogs were evaluated. Peptides corresponding to the TR region of US (TEDSVSAPATEDSVSAPA) and Brazilian E. canis strain (ASVVPEAEASVVPEAEASVVPEAE) and to the TRP19 E. canis epitope-containing region (HFTGPTFSEVNLSEEEKMELQEVS) were utilized as antigen. The peptide corresponding to the TRP36 C-teminal region from the E. canis Israeli strain (NPTGLKFLDLYTQLTL) was used as a negative peptide control. Six Brazilian dogs (n=6) had antibody that reacted with the novel Brazilian TRP36 peptide, and nine dogs reacted with the US TRP36 peptide. Most dogs (11/12) had antibodies that reacted with the TRP19 peptide, which is considered a highly conserved immunoreactive protein of E. canis. Four dogs had antibodies that reacted with both US and Brazilian TRP36 peptides suggesting infection with multiple E. canis genotypes, and one dog had antibodies to TRP19, but was not positive to either TRP36 peptides, suggesting the presence of an another novel TRP36 genotype circulating among the Brazilian dogs. Antibodies in sera from normal and experimentally infected with the E. canis USTRP36 genotype and E. chaffeensis did not react with the Brazilian TRP36. Our results demonstrate that synthetic peptides based on the TR region of E. canis TRP36 can be useful to identify and distinguish infections by different E. canis genotypes.