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Title: A HIGHLY CONSERVED EPITOPE ON THE SPIKE PROTEIN OF INFECTIOUS BRONCHITIS VIRUS

Author
item WANG, LI - TEXAS A & M UNIVERSITY
item PARR, REBECCA - TEXAS A & M UNIVERSITY
item King, Daniel
item COLLISSON, ELLEN - TEXAS A & M UNIVERSITY

Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Infectious bronchitis (IB) is an important viral respiratory disease of chickens and a cause of reduced weight gain, increased condemnations, and reduced egg production. The multiple serotypes of the IB virus (IBV) continue to change by mutation. Immunization is used, but the vaccine serotype and the flock infection must be the same for the best protection. . Ideally vaccine should protect against all serotypes. Comparisons of the amino acid sequence in the structure of the major surface protein of several IBV serotypes revealed a small highly conserved region that reacted with antisera to several IBV serotypes. The amino acids in the conserved region appear to provide stability to the function of the virus protein. Although antibody bound to the site does not neutralize the virus, the site may be biologically important for other processes, such as a role in virus attachment, a role that is probably conserved among serotypes and is critical for virus infection and multiplication. Identification of the viral function of the conserved region remains to be determined.

Technical Abstract: The predicted amino acid sequence and secondary structures of S1 of the spike protein (S) of infectious bronchitis viral (IBV) strains from Europe, the U.S.A., and Japan were compared. An antigenic determinant that was highly conserved in both the primary amino acid sequence and secondary structure of all strains was identified between amino acid positions 240 to 255. A synthesized peptide corresponding to this region was found to react with all polyclonal antisera examined from various IBV strains and with one monoclonal antibody (MAb), 9B1B6, out of nine known to react with the S of Gray. The specificity of the interaction with MAb 9B1B6 was confirmed by competitive ELISA using bound and unbound peptide. Interestingly, the previously described epitope for 9B1B6 had been characterized as cross-reactive with several strains of IBV, as conformation independent but reacting only with whole S, and as associated d with the functional integrity of other epitopes, including neutralizing epitopes on the S protein. The apparent critical functional and structural nature of this highly immunogenic determinant suggests a potential contribution in developing protective, cross-reactive subunit vaccines to IBV.