Sequence Analysis of the Spike Glycoprotein, Nucleocapsid Gene and 3' Untranslated Region of Razi Institute H-120 & H-52 Vaccine Strains of Infectious Bronchitis Virus

  Infectious bronchitis (IB) is an economically important disease of chickens. The existence of very large number of IBV serotypes and variants which insufficiently induce cross protection against each other is the major problem to control the disease. This study was performed to characterize S1, N and 3'UTR region of the genome of H-120 and H-52 vaccine strains of Razi Vaccine Institute. The S1, N and 3'UTR region were sequenced and compared with standard strain in gene bank. Based on nucleotide identity, the S1, N and 3'UTR region of the genome of Iranian IBV vaccine strain showed 100% similarity to the commonly standard IBV strains. To better characterization of these strains analysis of other genes involved in virulence and pathogenesis of the virus and performing protective tests against field strains are recommended. The results revealed that H-52 and H-120 strains of Razi institute were identical to the standard of strains in the Gene Bank.