Molecular characterization of avian reovirus isolates in Tunisia.

Virology Journal (Impact Factor: 2.09). 01/2013; 10(1):12. DOI: 10.1186/1743-422X-10-12
Source: PubMed

ABSTRACT BACKGROUND: Genotype analyses of avian reoviruses isolated from organ samples collected from chickens with suspicious clinical symptoms, between 1997--2008, was based on sequences for both sigmaC and sigmaB genes and aligned with those published in the Genbank, making it possible to carry out studies of molecular classification and relationships. METHODS: The full length of the known variable protein sigmaC and part of the sigmaB encoding genes, were amplified with RT-PCR, using conserved primers. PCR products were sequenced and the sequences were analyzed and aligned with avian reovirus sequences from the Genbank database. RESULTS: The sequences of sigmaC-encoding genes of all the isolated strains indicated their close relationship with the American, Chinese and Indian strains. Taking the American strain S1133 as a reference, the two Tunisian isolates 97.1 and 97.2 showed some nucleotide substitutions. For isolate 97.1, the substitution was silent whereas for strain 97.2 the mutation was at the first position of the corresponding codon and induced the substitution of the amino acid encoded. For the sigmaB-encoding gene, the sequences of the Tunisian strains showed mutations at positions two or three of the corresponding codons, inducing substitutions of amino acids at these positions. The phylogenic trees based on sigmaC and sigmaB encoding genes indicated closer relationship between Tunisian, American and Taiwanese isolates of genotype I. CONCLUSION: Our study describes the genotype of avian reoviruses that are not yet well characterized genetically. The characterization and classification of these viruses might be significant for understanding the epidemiology of malabsorption syndrome and viral arthritis, and improving our knowledge of the genotype of strains circulating in Tunisian flocks. Furthermore, the study of their variable pathogenicity could be extremely important in the choice of the appropriate vaccine strain to control disease.

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    ABSTRACT: Avian reovirus (ARV) causes arthritis, tenosynovitis, runting-stunting syndrome (RSS), malabsorption syndrome (MAS) and immunosuppression in chickens. σB is one of the major structural proteins of ARV, which is able to induce group-specific antibodies against the virus. The present study described the identification of two linear B-cell epitopes in ARV σB through expressing a set of partially overlapping and consecutive truncated peptides spanning σB screened with two monoclonal antibodies (mAbs) 1F4 and 1H3-1.The data indicated that (21)KTPACW(26) (epitope A) and (32)WDTVTFH(38) (epitope B) were minimal determinants of the linear B cell epitopes. Antibodies present in the serum of ARV-positive chickens recognized the minimal linear epitopes in Western blot analyses. By sequence alignment analysis, we determined that the epitopes A and B were not conserved among ARV, duck reovirus (DRV) and turkey reovirus (TRV) strains. Western blot assays, confirmed that epitopes A and B were ARV-specific epitopes, and they could not react with the corresponding peptides of DRV and TRV. We identified (21)KTPACW(26) and (32)WDTVTFH(38) as σB -specific epitopes recognized by mAbs 1F4 and 1H3-1, respectively. The results in this study may have potential applications in development of diagnostic techniques and epitope-based marker vaccines against ARV groups.
    PLoS ONE 11/2013; 8(11):e81533. · 3.53 Impact Factor

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May 30, 2014