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Immunoglobulin G1 enzyme-linked immunosorbent assay for diagnosis of Johne's Disease in red deer (Cervus elaphus).

Authors
  • Griffin, J Frank T1
  • Spittle, Evelyn
  • Rodgers, Christie R
  • Liggett, Simon
  • Cooper, Marc
  • Bakker, Douwe
  • Bannantine, John P
  • 1 Disease Research Laboratory, Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin, New Zealand. [email protected] , (New Zealand)
Type
Published Article
Journal
Clinical and Diagnostic Laboratory Immunology
Publisher
American Society for Microbiology
Publication Date
Dec 01, 2005
Volume
12
Issue
12
Pages
1401–1409
Identifiers
PMID: 16339063
Source
Medline
Language
English
License
Unknown

Abstract

This study was designed to develop a customized enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of Johne's disease (JD) in farmed deer. Two antigens were selected on the basis of their superior diagnostic readouts: denatured purified protein derivative (PPDj) and undenatured protoplasmic antigen (PpAg). ELISA development was based on the antigen reactivity of the immunoglobulin G1 (IgG1) isotype, which is a highly specific marker for mycobacterial disease seroreactivity in deer. Sensitivity estimates and test parameters were established using 102 Mycobacterium paratuberculosis-infected animals from more than 10 deer herds, and specificity estimates were determined using 508 uninfected animals from 5 known disease-free herds. A receiver-operated characteristic analysis determined that at a cut point of 50 ELISA units, there was a specificity of 99.5% and sensitivities of 84.0% with PPDj antigen, 88.0% with PpAg, and 91.0% when the antigens were used serially in a composite test. Estimated sensitivity was further improved using recombinant protein antigens unique for M. paratuberculosis, which identified infected animals that were unreactive to PPDj or PpAg. While 80% of animals that were seropositive in the IgG1 ELISA had detectable histopathology, the assay could also detect animals with subclinical disease. The test was significantly less sensitive (75%) for animals that were culture positive for M. paratuberculosis but with no detectable pathology than for those with pathological evidence of JD (>90%). When the IgG1 ELISA was used annually over a 4-year period in a deer herd with high levels of clinical JD, it eliminated clinical disease, increased production levels, and reduced JD-related mortality.

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