SvSXP: a Strongylus vulgaris antigen with potential for prepatent diagnosis

Particle and Fibre Toxicology

Martin K Nielsen⁴  Peter Nejsum³  Jesper Monrad³  Susanne N Olsen¹  Eugene T Lyons⁴  Craig R Reinemeyer²  Nils Toft¹  Sriveny Dangoudoubiyam⁴  Daniel K Howe⁴  Ulla V Andersen¹ 

[1] Department of Large Animal Science, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark;East Tennessee Clinical Research, Inc., Rockwood, TN, USA;Danish Centre for Experimental Parasitology, Department of Veterinary Disease Biology, Faculty of Health Science, University of Copenhagen, Frederiksberg, Denmark;M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA

关键词: Validation;    ELISA;    cDNA library;    Diagnosis;    Prepatent;    Strongylus vulgaris;    IgG(T);    SXP;   

Others  :  1228018
DOI  :  10.1186/1756-3305-6-84

 received in 2013-01-31, accepted in 2013-03-25,  发布年份 2013

【 摘 要 】

Background

Strongyle parasites are ubiquitous in grazing horses. Strongylus vulgaris, the most pathogenic of the large strongyles, is known for its extensive migration in the mesenteric arterial system. The lifecycle of S. vulgaris is characterised by a long prepatent period where the migrating larvae are virtually undetectable as there currently is no test available for diagnosing prepatent S. vulgaris infection. Presence of S. vulgaris larvae in the arterial system causes endarteritis and thrombosis with a risk of non-strangulating intestinal infarctions. Emergence of anthelmintic resistance among cyathostomins has led to recommendations of reduced treatment intensity by targeting horses that exceed a predetermined strongyle faecal egg count threshold. One study suggests an apparent increase in prevalence of S. vulgaris on farms where reduced anthelmintic treatment intensity has been implemented. These issues highlight the need for an accurate and reliable assay for diagnosing prepatent S. vulgaris infection.

Methods

Immunoscreening of a larval S. vulgaris cDNA library using hyperimmune serum raised against S. vulgaris excretory/secretory antigens was performed to identify potential diagnostic antigens. Immunoreactive clones were sequenced, one potential antigen was characterised, expressed as a recombinant protein, initially evaluated by western blot (WB) analysis, the diagnostic potential of the IgG subclasses was evaluated by ELISA, and the diagnostic accuracy evaluated using serum from 102 horses with known S. vulgaris infection status.

Results

The clone expressing the potential antigen encoded a S. vulgaris SXP/RAL2 homologue. The recombinant protein, rSvSXP, was shown to be a potential diagnostic antigen by WB analysis, and a target of serum IgGa, IgG(T) and total IgG in naturally infected horses, with IgG(T) antibodies being the most reliable indicator of S. vulgaris infection in horses. Evaluation of diagnostic accuracy of the ELISA resulted in a sensitivity of 73.3%, a specificity of 81.0%, a diagnostic odds ratio of 11.69; a positive likelihood ratio (LR) of 3.85 and a negative LR was 0.33. The area under the ROC curve was 0.820.

Conclusion

IgG(T) antibodies to recombinant SvSXP show potential for use as an antigen for prepatent diagnosis of migrating stages of S. vulgaris with moderate to good diagnostic accuracy.

【 授权许可】

   
2013 Andersen et al.; licensee BioMed Central Ltd.

【 图 表 】

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