Evaluation of a New Antibody-Based Enzyme-Linked Immunosorbent Assay for the Detection of Bovine Leukemia Virus Infection in Dairy Cattle

Abstract

Abstract. The objective of this study was to validate a new blocking enzyme-linked immunosorbent assay (ELISA) (designated M108 for milk and S108 for serum samples) for detecting bovine leukemia virus (BLV) infection in dairy cattle. Milk, serum, and ethylenediaminetetraacetic acid-blood samples were collected from 524 adult Holstein cows originating from 6 dairy herds in Central Argentina. The M108 and S108 were compared with agar gel immunodiffusion (AGID), polymerase chain reaction and a commercial ELISA. Because there is currently no reference test capable of serving as a gold standard, the test sensitivity (SE) and specificity (SP) were evaluated by the use of a latent class model. Statistical inference was performed by classical maximum likelihood and by Bayesian techniques. The maximum-likelihood analysis was performed assuming conditional independence of tests, whereas the Bayesian approach allowed for conditional dependence. No clear conclusion could be drawn about conditional dependence of tests. Results with maximum likelihood (under conditional independence) and posterior Bayes (under conditional dependence) were practically the same. Conservative estimates of SE and SP (with 95% confidence intervals) for M108 were 98.6 (96.7; 99.6) and 96.7 (92.9; 98.8) and for S108 99.5 (98.2; 99.9) and 95.4 (90.9; 98.1), respectively. The ELISA 108 using either milk or serum to detect BLV-infected animals had comparable SE and SP with the official AGID and a commercial ELISA test, which are currently the most widely accepted tests for the serological diagnosis of BLV infection. Therefore, ELISA 108 can be used as an alternative test in monitoring and control programs.

Enzyme-Linked Immunosorbent Assays Using the Recombinant gp51 and p24 of Bovine Leukemia Virus for Immunodetection of the Disease

“…During the immune response against BLV the synthesis and persistence of specific anti-p24 and anti-gp51 antibodies is lifelong [9] [19] [20], this features make these two highly immunogenic proteins as candidate to be included in any diagnostic test for EBL. Firstly, in this study we successfully produced a recombinant p24 protein with a proved antigenicity against the control sera, the bacterial expression system achieved a mass production of approximately 5.6 mg per liter cultures.…”

“…Structural proteins p24 and gp51 are potent immunogens and the antibody production can be detected in most of the animals infected with VLB. In experimentally infected animals anti-gp51 antibodies seem to be the first to appear with titres consistently higher than anti-p24 antibodies [7] [8] [9]. Other authors reports that high sensitivity tests are able to detect anti-p24 antibodies before the appearance of anti-gp51 antibodies; and the anti-p24 antibodies could be an equal or greater degree than anti-gp51 [3] [10].…”

“…The AGID, that mainly detects anti-gp51 antibodies [9], is a test with high specificity, low cost, quick and easy to perform, but with some main disadvantages like low sensitivity, time consuming for reading and subjective interpretation of test results and is unable to be performed with milk samples [12]. At the present, the detection of specific antibodies based on the recognition of crude antigens by AGID or ELISA requires mass production of the virus from persistently infected FLK cell lines cultures.…”

Evaluation of natural transmission of bovine leukaemia virus within dairy herds of Argentina

“…6-99 . 5) [28]. Serum samples were considered positive when their percentage of inhibition (PI) was >40 % of the standard positive, inconclusive when the PI was between 35 and 40 % and negative when the PI was <35 %.…”

Epidemiología de Plum pox virus y Citrus tristeza virus en bloques de plantas de vivero. Métodos de control

“…Los modelos latentes son utilizados en medicina y veterinaria para estimar la sensibilidad y la especificidad de diferentes pruebas de diagnóstico utilizando: funciones de máxima verosimilitud (Bruce et al, 1987;Claes et al, 2005;Nérette et al, 2005;Chu et al, 2009), métodos bayesianos (Orr et al, 2003;Sanford et al, 2006;Frey et al, 2009;de Clare Blonsvoort et al, 2010;Rose et al, 2010;van der Goot et al, 2010) o ambos (Enøe et al, 2001;Delaney et al, 2003;Monti et al, 2005;Engel et al, 2006;Mainar-Jaime y Barberán, 2007;Gari et al, 2008;Drewe et al, 2009). …”