Document Type: Original Article
Department of Veterinary Research and Biotechnology, Razi Vaccine and Serum Research Institute, Mashhad, Iran.
Department of Veterinary Research and Biotechnology, Razi Vaccine &amp; Serum Research Institute, Mashhad, Iran
Department of Poultry Disease Research and Diagnosis, Razi Vaccine and Serum Research Institute, Karaj, Iran.
Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
Neutralizing, serotype specific and haemagglutination-inhibiting antibodies against infectious bronchitis virus (IBV) are induced by epitopes in the S1 protein. Most changes in the virus genome due to mutation and recombination during serial passaging in embryonated chicken eggs occur in the S1 gene. We tried to predict the potential linear B-cell epitopes of the S1 subunit of two Iranian 793/B isolates and then we analyzed their changes at passage level 90 due to mutations at this passage level. To predict linear B-cell epitopes of the S1 protein belonging to two Iranian 793/B isolates, we used two online epitope prediction programs called BepiPred and ABCpred. Some of the most important features of proteins, including antigenicity, physicochemical properties and secondary structure composition were analyzed. The predicted epitopes were studied between wild viruses and their passage level 90 viruses. We identified 15 potential Linear B-cell Epitopes among which six epitopes had the highest scores of physicochemical properties and antigenicity. Due to amino acid substitutions seven predicted epitopes had different amino acid sequence at passage level 90. Among eight epitopes with no amino acid substitution at passage level 90, three epitopes had the highest scores. These three conserved epitopes including NH2-NQLGSCPLTGMI-COOH, NH2-GNFSDGFYPFTNSSLVKD-COOH and NH2-GPIQGGC-COOH might be strategic and potential candidates for use in designing epitope-based vaccine researches. In conclusion based on scores of physicochemical properties and antigenicity it seemed that the sequence of most epitopes in the wild viruses might be more antigenic and immunogenic compared to their sequence in viruses of passage 90.