Kamran Nazemi - Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, IRAN.
Arash Ghalyanchi Langeroudi - Department of Microbiology and immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran - IRAN
Masoud Hashemzadeh - Department of Research and Production of Poultry Viral Vaccine, Razi Vaccine and Serum Research Institute, Karaj, IRAN.
Vahid Karimi - Department of Avian Medicine, Faculty of Veterinary Medicine, University of Tehran, Tehran, IRAN.

Background: Avian infectious bronchitis (IB), with avianinfectious bronchitis virus (IBV) as the causing agent, is a ubiquitous endemicdisease of the chicken with devastating effects on its industry. A viralmembrane surface protein called S  notonly induces neutralizing antibodies but also plays an important role in virusbinding and entry to host cells. Technically, S1 protein gene sequencing alsohelps greatly in IBV genotyping. OBJECTIVES: The aim of this study wasto characterize Iranian IBV based on S2 gene. METHODS: After RT-PCRamplification, the S2 gene of nine Iranian IBV isolates were sequenced and thencompared with reference strains. RESULTS: The isolates were classifiedinto genotype I as Massachusetts like IB Vs, genotype VII which clustered intotwo branches, VIIa (IS-1494 like IB viruses), and VIIb, and was related to QX-like viruses and Genotype VIII as 793/B like IBVs. CONCLUSIONS: As faras we know, this is the first S2-based classification study on Iranian IBVisolates providing a firm experimental basis to correlate with genotypiccharacterization

Characterization, infectious bronchitis virus, genotyping, phylogenetic study, spike