Isolation Of Infectious Bronchitis Virus And Analysis Of N And S1Gene

Infectious bronchitis (IB) is an acute, highly contagious viral respiratory diseaseof chickens characterized by tracheal rales, coughing, and sneezing, caused byinfectious bronchitis virus(IBV). Recently, infectious bronchitis (IB) are epidemic inan area that result in serious economic loss. In order to discover the variation of IBepidemic isolates and the reasons of frequent occurrence, using the vaccine to controlthe epidemic disease, we did some research on isolation, genome sequence andantigenicity analysis.Two virus strains were isolated from the lung,bronchial and kidney of the sickchicken and identified to be infectious bronchitis virus (IBV) by by using chickembryo culture, hemagglutination (HA) test, chicken inoculation and RT-PCR, namedGY and HQ strain.A pair of specific primer was designed and synthesized according to thesequence of N gene and S1gene of IBV published in GenBank. N gene of GY andHQ strains have some point mutations widely, and maybe appeared generecombination. The homologies of nucleotide sequences and amino acid sequences ofN gene of GY strain with GX-YL1strain were approximately about97.2%and97.6%;the homologies of nucleotide sequences and amino acid sequences of N gene of HQstrain with JH06111strain were approximately about98.9%and98.5%, HQ,JH06111, GX-NN9and SC021201strains were in a independent branch; thehomologies of nucleotide sequences and amino acid sequences of N gene of GY andHQ strains with H120strain were approximately about90.7%lower, it has a distantrelationship. S1gene of GY and HQ strains not only have some point mutationswidely, but also have insertion. The homologies of nucleotide sequences and aminoacid sequences of S1gene of GY strain with CK/CH/LSD/091159strain wereapproximately about99.0%and98.5%; the homologies of nucleotide sequences of S1gene of HQ strain with CK/CH/Zhejiang/Quzhou3/0910strain were approximatelyabout99.6%, the homologies of amino acid sequences with XX09-3wereapproximately about99.1%;the homologies of nucleotide sequences and amino acid sequences of S1gene of HQ and GY strains with H120strain were77.5%lower,while is far away from vaccine stain H120.Using ciliary activity of chick embryo tracheal organ cultures(TOC)as a indicatorsystem, two infectious Bronchitis isolates and vaccine stain H120were checked in thecross-neutralizatfon test. Two isolates were compared with vaccine stain H120, wecan find that R of these three strains were0.4258,0.7034,0.4491,they belonged tohomologous serotype, but antigenic relevance was lower.The results showed that N and S1gene of IBV have mutation widely, in the sametime, the another reason for variation of IBV may be recombination; there was noinevitable relation with the homologies of IBV nucleotide sequences and amino acidsequences,genetic evolution, pathogenicity, tissue tropism and serotype.