Untitled

Abstract

The infectious bronchitis virus (IBV) spike glycoprotein S1 subunit is required to initiate infection and contains virus-neutralizing and serotype-specific epitope(s). Reported are the S1 gene nucleotide and predicted amino acid sequences for the Florida 18288 strain and isolates GA-92, CV-56b, CV-9437, CV-1686, and 1013. These sequences were compared with previously published gene sequences of IBV strains, and phylogenetic relationships are reported. The S1 amino acid sequence of Florida 18288 was 94.9% similar to the Connecticut strain, and GA-92 was 92.8% similar to the Arkansas 99 strain. S1 amino acid sequences of the California variants, CV-56b, CV-9437, and CV-1686, were 97.6-99.3% similar to one another and only 76.6%-76.8% similar to the Arkansas-type strains. Isolate 1013, also from California, was 84.0% similar to Ark DPI and 77.9% similar to CV-56b. When comparing 19 viruses isolated from the United States, sequence variations were observed between amino acids 55-96, 115-149, 255-309, and 378-395. Similar regions are reported to be involved in virus-neutralizing and/or serotype-specific epitopes. These data demonstrate that variant IBV strains continue to emerge, and unique variants may circulate among poultry in geographically isolated areas.

Characterization of a new genotype and serotype of infectious bronchitis virus in Western Africa

“…This subunit is responsible for inducing neutralizing and serotype-specific antibodies. Mutations within this genome region may therefore result in the emergence of new variants against which vaccines are no longer protective (Moore et al, 1998). IBV causes significant economic losses, mostly because of reduced productivity rather than bird mortality (Cavanagh & Naqi, 2003).…”

Complete Nucleotide Sequences of S1 and N Genes of Infectious Bronchitis Virus Isolated in Japan and Taiwan

“…Although CV-1686 (the California variant) did contain the 5 amino acid insertion, the S1 proteins of CV-1686 and other California variants exhibited a number of unique features that were distinct from other viruses. For example, CV-1686 and other California variants [7], all had the 3 amino acid deletion located at residues 57-59 of the S1 protein (Fig. 2, within the area indicated by HVR-1).…”

“…1). In this tree, strains JP8127, JP8443 and JP9758 fell into the branch containing viruses isolated from Australia [8], New Zealand and California [7] (Fig. 1).…”

“…1). Note that the Australian viruses (N9/74, N3/62 and N1/62) in this branch were known as classical Australian strains [8], whereas the California viruses (CV-1686 and CV-56b) in this branch were known as "California variants" [7]. It was also noteworthy that the strain KB8523, isolated in Japan in 1983 [10], formed a single lineage with strain H120, which was the most widely used live vaccine strain for the control of IBV (Fig.…”

Using DNA Shuffling to Create Novel Infectious Bronchitis Virus S1 Genes: Implications for S1 Gene Recombination

“…Each of the recombinants contained a cleavage sequence of the type X 1 RX 2 RR, where X 1 represents Arg, His, or Tyr and X 2 represents Ser, Phe, Ile, Arg, or His [22,23]. The number of potential N-linked glycosylation sites ranged from 17 to 18.…”