Development of a recombinant vaccine against infectious coryza in chickens

Infectious coryza is an acute respiratory disease of chickens caused by Avibacterium paragallinarum, and this infection is associated with growth retardation and reduced egg production. Previous studies have shown that HMTp210, a 210-kDa outer-membrane protein, is the major protective antigen of Av. paragallinarum both serovars A and C. Region 2 is a serovar-specific domain in the HMTp210 protein. Although the serovar C region 2 has been reported to be an effective vaccine antigen for infectious coryza, there have been no reports on the efficacy of region 2 from serovar A. In the current study, region 2 from serovars A and C was expressed as a fusion peptide. Chickens inoculated with vaccine consisting of 0.6 μg of the fusion peptide showed no clinical signs of disease after challenge with either serovar A or C, and there were no side effects such as swelling at the injection site. These results demonstrate that the recombinant fusion peptide derived from HMTp210 could be useful for producing effective and safe vaccines against infectious coryza in chickens.