Aliakbar Khabiri; Reza Toroghi; Mohammadreza Mohammadabadi; Seyed-Elias Tabatabaeizadeh
Volume 14, Issue 4 , April 2023, , Pages 221-228
Abstract
Newcastle disease virus (NDV) sub-genotype VII.1.1 is the most common circulating NDV in Iran. In this study, a velogenic NDV isolate was plaque purified and then characterized according to Office International des Epizooties (OIE) standard protocols. The biological properties of the purified isolate ...
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Newcastle disease virus (NDV) sub-genotype VII.1.1 is the most common circulating NDV in Iran. In this study, a velogenic NDV isolate was plaque purified and then characterized according to Office International des Epizooties (OIE) standard protocols. The biological properties of the purified isolate named CH/RT40/IR/2011 were characterized using sequencing and phylogenetic analysis, measurement of pathogenicity indexes and challenge studies. The isolate was plaque purified on chicken embryo fibroblast cells for three rounds and then characterized using molecular and biological approaches. Phylogenetic and evolutionary distance analysis of fusion and hemagglutinin-neuraminidase genes classified the virus in sub-genotype VII.1.1. No mutation was observed in the glycosylation and neutralizing epitope sites of the fusion and hemagglutinin-neuraminidase proteins compared to other reported Iranian NDV VII.1.1 isolates. The presence of the 112RRQKRF117 motif in the fusion protein cleavage site together with mean death time, intracerebral pathogenicity index and intravenous pathogenicity index of 57 hr, 1.80 and 2.50 respectively, revealed that the RT40 isolate was a velogenic NDV. In the challenge study, all chickens were inoculated via eye drop, and intranasal route with RT40 isolate died within a week. While all chickens in the vaccinated and challenged group survived and showed no clinical signs. In conclusion, according to genetic analysis, pathotyping and challenge study, the RT40 isolate was similar to virulent NDVs in Iran and was a suitable candidate for a national standard challenge strain, vaccine trials and vaccine production in commercial levers.
Arezoo Salarpour; Reza Toroghi; Gholamreza Nikbakht Brujeni; Reza Momayez
Volume 11, Issue 4 , December 2020, , Pages 365-370
Abstract
Neutralizing, serotype-specific, and hemagglutination-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. ...
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Neutralizing, serotype-specific, and hemagglutination-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. In the current study, 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 sequences 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,andNH2-GPIQGGC-COOHmight 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 wild viruses might be more antigenic and immunogenic compared to their sequence in viruses of passage 90.
