Genetic analysis revealed LX4 genotype strains of avian infectious bronchitis virus became predominant in recent years in Sichuan area, China

Abstract

Between 2008 and 2010, 19 strains of infectious bronchitis virus (IBV) were isolated from the vaccinated chicken flocks in Sichuan province, China. The S1 genes of the isolates were amplified and sequenced. Phylogenetic analysis revealed that the 19 isolates and 37 reference IBV strains can be grouped into eight genotypes. Although IBVs of Taiwan-I type, massachusetts type, and proventriculitis type were isolated, but most isolates were LX4 genotype. Homology analysis of the sequences of S1 genes of the 19 isolates and 37 reference IBV strains revealed that the identity of the nucleotides and amino acid sequences of the S1 genes between the 15 LX4-type isolates and other IBV strains were 71.9-99.3% and 72.1-99.1%, respectively, while those of the analyzed IBV of LX4 type were 96.0-99.9% and 94.3-99.8%, respectively. The results from this study and other published results in the GenBank database showed that isolates circulating in Sichuan province in recent years were mainly LX4 genotype, which is the predominant genotype circulated in China in recent years.

Two novel neutralizing antigenic epitopes of the s1 subunit protein of a QX-like avian infectious bronchitis virus strain Sczy3 as revealed using a phage display peptide library

“…The myeloma cell line SP2/0 was purchased from the ATCC and cultured in Dulbecco's modified eagle medium (DMEM, Gibco BRL, Paisley, UK) with 10% fetal calf serum (FCS, Gibco), and maintained at 37 • C and 5% CO2. IBV Sczy3 strain was isolated in 2009 from a broiler chickens in Sichuan Province (Zou et al, 2010). Other ten IBV strains from 5 different genotypes were selected for cross-reaction analysis ( Table 1, marked with c ).…”

“…Although vaccines are now being used widely and extensively, outbreaks of IB still occur frequently because of infections with field strains that differ serologically from vaccine strains Zou et al, 2010;Mahmood et al, 2011).…”

Dynamic changes of virus load in supernatant of primary CEK cell culture infected with different generations of avian infectious bronchitis virus strains Sczy3 as revealed by real-time reverse transcription-polymerase chain reaction

“…The strain was shown to be a QX-like IBV based on genetic analysis (Zou et al, 2010). The stock virus was propagated in 9-11-day-old specific pathogen-free chicken embryos (Beijing Experimental Animal Center, Beijing, China), and the allantoic fluids were harvested 36 h post-inoculation and stored at -70°C.…”

Recombinant infectious bronchitis coronavirus H120 with the spike protein S1 gene of the nephropathogenic IBYZ strain remains attenuated but induces protective immunity

“…The QX-like genotype is thought to have originated during the mid-1990s and continues to be the predominant strain, whereas the LDT3, 4/91, and Taiwan subtypes have also recently been frequently isolated in China [10][11][12][13]. Severe nephritis, false layer syndrome, and high mortality are observed in chickens infected with this viral genotype, which represents a major problem in the poultry industry, particularly in China.…”