title: Immunogenicity and haemagglutination of recombinant Avibacterium paragallinarum HagA.
abstract: Inactivated vaccines of Avibacterium paragallinarum provide protection and reduce the economic losses caused by infectious coryza. However, inactivated bacterins provide protection only against the Page serovars included in the vaccine. In this study, we investigated the immunological properties of a functional recombinant haemagglutinin protein (rHagA) derived from a Taiwan isolate strain A9 as the immunogen for vaccination. The rHagA subunit vaccine protected 71% of immunized chickens against 10(10) colony-forming units (CFU) of viable A9. Vaccinated chickens which showed no clinical signs of coryza developed haemagglutination inhibition (HI) titers of 1:10 or greater. Haemagglutination (HA) of serovars A and C was not affected by the presence of rHagA specific antiserum. The HA of rHagA could only be induced against formaldehyde-fixed chicken red blood cells (FA-RBCs). These results suggested that HagA is a moderate immunogen and might not be a major haemagglutinin in vivo. However, HagA might be involved in haemagglutination when treated serovar C aggregates fixed RBCs in vitro.
authors.affiliation: Department of Biological Science and Technology, China Medical University, Taichung, Taiwan. yuanmh@mail.cmu.edu.tw
authors.forename: Yuan-Man
authors.initials: YM
authors.lastname: Hsu
authors.forename: Happy K
authors.initials: HK
authors.lastname: Shieh
authors.forename: Wei-Hao
authors.initials: WH
authors.lastname: Chen
authors.forename: Jia-Hsiang
authors.initials: JH
authors.lastname: Shiang
authors.forename: Poa-Chun
authors.initials: PC
authors.lastname: Chang
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology*; D002645:Chickens; D015169:Colony Count, Microbial / Q000662:veterinary; D006192:Haemophilus Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D044134:Haemophilus paragallinarum / Q000276:immunology*; D006385:Hemagglutination Inhibition Tests / Q000662:veterinary; D006388:Hemagglutinins; D011201:Poultry Diseases / Q000382:microbiology / Q000517:prevention & control*; D011994:Recombinant Proteins; D013047:Specific Pathogen-Free Organisms; D015164:Vaccines, Inactivated / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D006388:Hemagglutinins; D011994:Recombinant Proteins; D015164:Vaccines, Inactivated