Development of a blocking enzyme-linked immunosorbent assay for the detection of avian polyomavirus-specific antibodies

Avian polyomavirus, described originally as budgerigar fledgling disease vi rus, has been associated with devastating contagious disease outbreaks in b udgerigar aviaries. At present, this virus affects a wide range of psittaci ne and non-psittacine birds worldwide, and the serum neutralisation test is used for the serodiagnosis of avian polyomavirus infections. A blocking en zyme-linked immunosorbent assay was developed for the screening of large nu mbers of sera collected from various avian species. The assay employs a mon oclonal antibody directed against the major structural protein VP1 as a blo cking antibody in a sandwich blocking procedure. Either purified avian poly omavirus particles or avian polyomavirus VP1 expressed in recombinant bacul ovirus-infected Sf9 cells were used as antigen. The specificity of the bloc king enzyme-linked immunosorbent assay was evaluated by testing sera direct ed against mammalian polyomaviruses. Using sera obtained from chicken infec ted experimentally with avian polyomavirus and a collection of psittacine f ield-origin sera, a good correlation was observed between the results of th e blocking enzyme-linked immunosorbent assay and the serum neutralisation t est. However, the blocking enzyme-linked immunosorbent assay is more rapid and more economic. Both, avian polyomavirus particles and VP1 produced by r ecombinant DNA technology proved to be suitable antigens. (C) 2000 Elsevier Science B.V. All rights reserved.