title: Antigenic evaluation of a recombinant baculovirus-expressed Sarcocystis neurona SAG1 antigen.
abstract: Sarcocystis neurona is the primary parasite associated with equine protozoal myeloencephalitis (EPM). This is a commonly diagnosed neurological disorder in the Americas that infects the central nervous system of horses. Current serologic assays utilize culture-derived parasites as antigen. This method requires large numbers of parasites to be grown in culture, which is labor intensive and time consuming. Also, a culture-derived whole-parasite preparation contains conserved antigens that could cross-react with antibodies against other Sarcocystis species and members of Sarcocystidae such as Neospora spp., Hammondia spp., and Toxoplasma gondii. Therefore, there is a need to develop an improved method for the detection of S. neurona-specific antibodies. The sera of infected horses react strongly to surface antigen 1 (SnSAG1), an approximately 29-kDa protein, in immunoblot analysis, suggesting that it is an immunodominant antigen. The SnSAG1 gene of S. neurona was cloned, and recombinant S. neurona SAG1 protein (rSnSAG1-Bac) was expressed with the use of a baculovirus system. By immunoblot analysis, the rSnSAG1-Bac antigen detected antibodies to S. neurona from naturally infected and experimentally inoculated equids, cats, rabbit, mice, and skunk. This is the first report of a baculovirus-expressed recombinant S. neurona antigen being used to detect anti-S. neurona antibodies in a variety of host species.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Gupta
authors.forename: J
authors.initials: J
authors.lastname: Lakritz
authors.forename: W J
authors.initials: WJ
authors.lastname: Saville
authors.forename: R S
authors.initials: RS
authors.lastname: Livingston
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: J R
authors.initials: JR
authors.lastname: Middleton
authors.forename: A E
authors.initials: AE
authors.lastname: Marsh
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D002415:Cats; D004679:Encephalomyelitis / Q000175:diagnosis / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D006734:Horse Diseases / Q000175:diagnosis* / Q000276:immunology / Q000469:parasitology; D006736:Horses; D015151:Immunoblotting / Q000662:veterinary; D012889:Mephitidae; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology*; D011817:Rabbits; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012522:Sarcocystis / Q000235:genetics / Q000276:immunology*; D012523:Sarcocystosis / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C097089:p31 protein, Sarcocystis