|Cheevers, William - WASHINGTON STATE UNIV.|
|Marshall, Katherine - APHIS|
|Mc Guire, Travis - WASHINGTON STATE UNIV.|
|Hutton, Melinda - WASHINGTON STATE UNIV.|
Submitted to: Clinical and Diagnostic Laboratory Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 20, 2003
Publication Date: September 20, 2003
Citation: HERRMANN, L.M., CHEEVERS, W.P., MARSHALL, K.L., MC GUIRE, T.C., HUTTON, M.M., LEWIS, G.S., KNOWLES JR, D.P. DETECTION OF SERUM ANTIBODIES TO OVINE PROGRESSIVE PNEUMONIA VIRUS (OPPV) IN SHEEP USING A CAPRINE ARTHRITIS-ENCEPHALITIS VIRUS (CAEV) COMPETITIVE-INHIBITION ENZYME-LINKED IMMUNOSORBENT ASSAY (CELISA). CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY. 2003. v. 10 p. 862-865. Interpretive Summary: Ovine progressive pneumonia virus (OPPV) is a lentivirus capable of causing pneumonia and mastitis in some sheep. Therefore, improved diagnostic tests for the detection of OPPV infection are necessary. This study describes the validation of a caprine arthritis-encephalitis virus (CAEV) competitive enzyme linked immunosorbant assay (cELISA) for detection of OPPV serum antibodies in sheep. The high sensitivity (98.6%) and specificity (96.9%) of this test in sheep makes this test an extremely useful tool for successful eradication of OPPV.
Technical Abstract: A competitive-inhibition enzyme-linked immunosorbent assay (cELISA) for detection of antibodies to the surface envelope (SU) of caprine arthritis-encephalitis virus (CAEV) was recently reported (Herrmann, L.M., W.P. Cheevers, T.C. McGuire, D. Scott Adams, M.M. Hutton, W.G. Gavin, D.P. Knowles. 2003. Clin. Diag. Lab. Immunol. v. 10, p.267-271). The cELISA utilizes CAEV-63 SU captured on microtiter plates using monoclonal antibody (mAb) F7-299 and measures competitive displacement of binding of anti-CAEV mAb GPB 74A by goat serum. The present study evaluated the CAEV cELISA for detection of antibodies to ovine progressive pneumonia virus (OPPV) in sheep. Three hundred thirty-two sera were randomly selected from 21,373 sheep sera collected throughout the United States to determine the sensitivity and specificity of cELISA and agar gel immunodiffusion (AGID) based on immunoprecipitation (IP) of [35S] methionine-labeled OPPV antigens as a standard of comparison. A positive cELISA test was defined as > 20.9 percent inhibition (% I) of mAb 74A binding based on two standard deviations above the mean % I of 191 IP-negative sheep sera. At this cutoff, there were 2/141 false-negative sera (98.6 % sensitivity) and 6/191 false-positive sera (96.9 % specificity). Sensitivity and specificity values for IP-monitored AGID were comparable to cELISA for 314 of 332 sera with unambiguous AGID results. Concordant results by cELISA and IP resolved 16 of the 18 sera that were indeterminate by AGID. Additional studies evaluated cELISA using 539 sera from a single OPPV-positive flock. Based on IP of 36 of these sera, there was one false-negative by cELISA among 21 IP-positive sera (95.5% sensitivity) and 0/15 false-positives (100 % specificity). We conclude that the CAEV cELISA can be applied to detection to OPPV antibodies in sheep with high sensitivity and specificity.