title: Purification, N-terminal sequencing and diagnostic value of the major antigens of Ornithodoros erraticus and O. moubata.
abstract: To enhance the specificity and sensitivity of serological detection of swine exposed to Ornithodoros erraticus or O. moubata, we purified the 158, 186, 215 and 260 kDa antigens from the former species and the designated (owing to their MW and charge) 19C, 17A, 20A1 and 20A2 antigens of the latter by HPLC and gel electroelution methods. All the O. erraticus antigens share epitopes and are difficult to purify individually by reverse phase and ion-exchange chromatography due to their molecular similarity. Tested individually by ELISA, all of them give the same optical densities (OD) with anti-O. erraticus sera, and these ODs are always lower with anti-immature than with anti-adult sera. Although immature and adult specimens have the same antigens, immature forms induce more anti-carbohydrate antibodies than adults. This is the reason for the lower ODs of the anti-immature sera against purified antigens, since these latter antigens essentially react with anti-peptide antibodies (hence, increasing the specificity and sensitivity of the serology). The N-terminus of the 260 kDa antigen shows 80-90% similarity with the hemoglobin alpha-chain of many mammals. The antigens of O. moubata are proteins that are very different from one another and are, therefore, readily purified by ion exchange chromatography. The 20A1 antigen appears to be the most immunogenic and is recognized equally by anti-immature and anti-adult sera. This antigen does not give false positive reactions with the negative control sera analyzed and its N-terminus region shares 46.2% homology with the alpha-chain of the C3 component of rabbit complement.
authors.affiliation: Laboratorio de Parasitología, Facultad de Farmacia, Universidad de Salamanca, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Baranda
authors.forename: R
authors.initials: R
authors.lastname: Pérez-Sánchez
authors.forename: A
authors.initials: A
authors.lastname: Oleaga
authors.forename: R
authors.initials: R
authors.lastname: Manzano
authors.forename: A
authors.initials: A
authors.lastname: Encinas-Grandes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000097:blood; D000941:Antigens / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D002852:Chromatography, Ion Exchange / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D011817:Rabbits; D012680:Sensitivity and Specificity; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013552:Swine; D013553:Swine Diseases / Q000175:diagnosis*; D013984:Tick Infestations / Q000175:diagnosis / Q000662:veterinary*; D013987:Ticks / Q000737:chemistry / Q000276:immunology*
chemical_list: D000906:Antibodies; D000941:Antigens