Recombinant proteins containing the hypervariable region of the haemagglutinin protect chickens against challenge with Avibacterium paragallinarum.
The haemagglutinin (HA) protein plays a key role in the immunogenicity and pathogenicity of Avibacterium paragallinarum, but the domain organization and antigenicity exhibited by different domains of this protein remain unknown. This study reports the presence of a hypervariable region in the HA proteins of strains of serovars A and C of A. paragallinarum. This hypervariable region is located approximately at residues 1100-1600 of the HA protein. The sequence identity found in this hypervariable region was only 18.1%, whereas those upstream and downstream of this region were 83.8 and 97.8%, respectively. Western blot analyses using antisera against the whole-cell antigens of A. paragallinarum showed that the hypervariable region was more antigenic than other regions of the HA protein. Moreover, the antigenicity of the hypervariable region was serovar-specific. Chickens immunized with recombinant proteins that contained the hypervariable region were protected (83-100% protection rate) against challenge infection with A. paragallinarum of the homologous serovar. These results suggest that recombinant proteins containing the hypervariable region may be useful antigens for use in the development of a vaccine against A. paragallinarum.
Graduate Institute of Microbiology and Public Health, National Chung Hsing University, #250 Kuokuang Road, Taichung 402, Taiwan.
Jin-Ru
JR
Wu
Yi-Ru
YR
Wu
Jui-Hung
JH
Shien
Yuan-Man
YM
Hsu
Chih-Feng
CF
Chen
Happy K
HK
Shieh
Poa-Chun
PC
Chang
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology*; D015153:Blotting, Western; D002645:Chickens; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D006388:Hemagglutinins / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D015661:Pasteurellaceae / Q000235:genetics / Q000276:immunology*; D016871:Pasteurellaceae Infections / Q000401:mortality / Q000517:prevention & control / Q000662:veterinary*; D011110:Polymorphism, Genetic; D011201:Poultry Diseases / Q000401:mortality / Q000517:prevention & control*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D016019:Survival Analysis; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D004269:DNA, Bacterial; D006388:Hemagglutinins; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic