Molecular characterization of recent Iranian infectious bronchitis virus isolates based on S2 protein gene

Avian infectious bronchitis (IB), with avian infectious bronchitis virus (IBV) as the causing agent, is a ubiquitous endemic disease of the chicken with devastating effects on its industry. A viral membrane surface protein called S not only induces neutralizing antibodies but also plays an important role in virus binding and entry to host cells. Technically, S1 protein gene sequencing also helps greatly in IBV genotyping.
The aim of this study was to characterize Iranian IBV based on S2 gene.
After RT-PCR amplification, the S2 gene of nine Iranian IBV isolates were sequenced and then compared with reference strains.
The isolates were classified into genotype I as Massachusetts like IB Vs, genotype VII which clustered into two branches, VIIa (IS-1494 like IB viruses), and VIIb, and was related to QX- like viruses and Genotype VIII as 793/B like IBVs.
As far as we know, this is the first S2-based classification study on Iranian IBV isolates providing a firm experimental basis to correlate with genotypic characterization