Fowlpox virus structural protein immunogens and characterization of single band polypeptide

A fowlpox virus isolate obtained from an outbreak of disease in a vaccinated poultry flock was propagated in chicken embryo fibroblast cell culture. Analysis of purified virus polypeptide on 7.5-15% gradient polyacrylamide gel revealed 45 structural polypeptides after Coomassie blue staining. The mol.wt. of polypeptides ranged between 225.53 and 10.50 kDa with total mol.wt. of 2650 kDa. Variable numbers of immunogenic virion polypeptides were detected in immunoblot with fowlpox virus infected chicken sera collected at different time intervals. A total of 29 polypeptides reacted with sera collected at 1st week post-infection and the number gradually declined to 27, 26, 20, 17 and 15 when reacted with 2nd, 3rd, 4th, 5th and 6th week post-infection sera, respectively. Reaction with fowlpox virus hyperimmune sera revealed 35 immunogenic polypeptides. A number of major and minor immunogens were detected. Antisera against seven major single band polypeptides including one double band polypeptide showed very low reactivity both in ELISA and serum neutralization test. Involvement of multigenic components in virus neutralization is indicated.