title: Development of ELISA test for determination of the level of antibodies against Rhodococcus equi in equine serum and colostrum.
abstract: Rhodococcus equi infection occurs worldwide and is one of the major causes of losing foals in the first six months of life. The application of serological tests in the diagnostics of rhodococcosis is limited, however they play a crucial role in immunological studies. The objective of this study was to develop and standardize ELISA test for the determination of the level of antibodies against Rhodococcus equi in equine serum and colostrum.Bacterial cell lysate was used as antigen. The test was standardized on 175 sera obtained from adult horses kept on rhodococcosis-free and endemic farms. Positive and negative control sera were used. The test detected IgG antibodies mainly against VapA protein, which was confirmed by Western blot analysis. The test was easy to perform, did not require inactivation of sera and had low well-to-well variation. The shelf life of antigen-coated ELISA plates was 21 days.The test allowed to reveal significant increase of R. equi-specific antibodies in both serum and colostrum in response to the vaccination (p<0.001). Therefore it can be applied to the evaluation of efficacy of immunization. Moreover, no statistically significant difference in the baseline antibody level in adult horses from rhodococcosis-free and endemic farm was revealed (α=0.05).
authors.affiliation: Division of Infectious Diseases and Epidemiology, Department of Large Animal Diseases with the Clinic, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 159c, 02-776 Warsaw, Poland. lucjan_witkowski@sggw.pl
authors.forename: Lucjan
authors.initials: L
authors.lastname: Witkowski
authors.forename: Jarosław
authors.initials: J
authors.lastname: Kaba
authors.forename: Magdalena
authors.initials: M
authors.lastname: Rzewuska
authors.forename: Mariusz
authors.initials: M
authors.lastname: Nowicki
authors.forename: Olga
authors.initials: O
authors.lastname: Szaluś-Jordanow
authors.forename: Jerzy
authors.initials: J
authors.lastname: Kita
mesh_terms: D000193:Actinomycetales Infections / Q000097:blood / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis* / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology; D003126:Colostrum / Q000737:chemistry* / Q000276:immunology / Q000382:microbiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D005260:Female; D006734:Horse Diseases / Q000097:blood / Q000276:immunology* / Q000382:microbiology*; D006736:Horses; D015203:Reproducibility of Results; D016929:Rhodococcus equi / Q000276:immunology*; D018709:Statistics, Nonparametric
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; C541879:VapA protein, Rhodococcus equi