Antigenic and immunogenic properties of baculovirus-expressed infectious bursal disease viral proteins.
Genomic segment A of the variant Md infectious bursal disease virus (IBDV) was amplified by reverse transcriptase/polymerase chain reaction, cloned, and expressed in the baculovirus expression system. Three different baculovirus recombinants expressing the genes encoding VP2, VP2/VP4, and the complete polyprotein (VP2/VP4/VP3) were prepared. The three antigens were used in separate enzyme-linked immunosorbent assays, and each detected antibodies against the variant IBDV strains Md, Del-A, Del-E, and GLS and the classic IBDV strain D78 throughout a 14-wk period following vaccination. Eight-week-old specific-pathogen-free (SPF) chickens were inoculated subcutaneously using the VP2/VP4 or VP2/VP4/VP3 baculovirus recombinant or wild-type baculovirus-infected insect cell lysates. Virus-neutralizing antibodies were detected in the VP2/VP4 and VP2/VP4/VP3 baculovirus-inoculated birds at 13 days postinoculation (PI) and at 43 days PI when titrated against Md IBDV. No virus-neutralizing antibody titer was observed in the negative controls or wild-type baculovirus-inoculated birds. One-week-old SPF chickens were inoculated with the VP2, VP2/VP4/VP3 baculovirus recombinants or wild-type baculovirus-infected insect cell lysates. The birds were boosted 2 wk later and challenged at 4 wk of age with 0.5 ml/bird classic STC IBDV (10(2) median embryo infective dose [EID50]/ml) or variant Md IBDV (10(5) EID50/ml) via the oral/nasal route. The VP2 and VP2/VP4/VP3 baculovirus-inoculated birds were partially protected against challenge with the classic STC IBDV. The birds were protected against clinical disease and death but not bursal damage, whereas the wild-type baculovirus-inoculated birds exhibited clinical signs of disease, 13% mortality, and bursal damage. When challenged with the variant Md IBDV, neither the VP2, VP2/VP4/VP3 baculovirus recombinants nor the wild-type baculovirus elicited protection against bursal damage and atrophy.
Dybing
J K
JK
Department of Veterinary Preventive Medicine, Ohio Agricultural Reseach and Development Center, Ohio State University, Wooster 44691, USA.
Jackwood
D J
DJ
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000096:biosynthesis / Q000276:immunology*; D002213:Capsid / Q000096:biosynthesis / Q000276:immunology*; D002460:Cell Line; D002645:Chickens; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005822:Genetic Vectors; D009980:Influenza A virus / Q000235:genetics / Q000276:immunology*; D005585:Influenza in Birds / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D008297:Male; D017924:Nucleopolyhedroviruses; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology; D018411:Spodoptera; D014162:Transfection
D000914:Antibodies, Viral; D000956:Antigens, Viral; D011994:Recombinant Proteins