Evaluation of a competitive ELISA for detection of antibodies against avian influenza virus nucleoprotein.
A competitive enzyme-linked immunosorbent assay (C-ELISA) employing a baculovirus-expressed recombinant nucleoprotein and a monoclonal antibody was developed for the detection of antibodies to type A influenza virus nucleoprotein. The performance of the C-ELISA was evaluated by testing 756 chickens, 1123 turkeys, 707 emus, and 1261 ostriches, for a total of 3847 serum samples. Relative to the agar gel immunodiffusion (AGID) test, the C-ELISA had a sensitivity of 100% for all four species. The C-ELISA's sensitivity relative to the hemagglutination-inhibition (HI) test results was 100% for chicken, turkey, and emu and 96.2% for the ostrich serum samples. More than 90% of the AGID-negative/C-ELISA-positive serum samples were found positive by HI for at least one influenza serotype. The specificity of C-ELISA relative to AGID ranged from 85.5% to 99.8% for sera collected from these species. These results indicated that the C-ELISA was more sensitive and more specific than the AGID test and as sensitive and as specific as the HI test. The C-ELISA has the potential to replace the AGID test for screening sera from avian species, including ratites, for detection of antibodies to type A influenza virus.
Animal Diseases Research Institute, Canadian Food Inspection Agency, Nepean, Ontario, Canada.
E M
EM
Zhou
M
M
Chan
R A
RA
Heckert
J
J
Riva
M F
MF
Cantin
D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D002645:Chickens / Q000276:immunology / Q000821:virology; D020312:Dromaiidae / Q000276:immunology / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay; D009980:Influenza A virus / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology / Q000821:virology; D009698:Nucleoproteins / Q000276:immunology*; D020310:Struthioniformes / Q000276:immunology / Q000821:virology; D014422:Turkeys / Q000276:immunology / Q000821:virology
D000914:Antibodies, Viral; D009698:Nucleoproteins