The development and evaluation of a multi-epitope antigen as a serodiagnostic marker of Toxoplasma gondii infection

Abstract

Background.Toxoplasmagondii(T.gondii)isaubiquitousprotozoanparasitewhichcausesaseriousdisease called toxoplasmosis. The high prevalence of T. gondiiinfection has attracted a great deal of interest in its diagnosisandtreatment.Theuseofpureantigensshowshighsensitivityandspecificity,butchallengessuch ascross-reactivityremaindiagnosticdifficulties. Objectives.Theaimofthisstudywastouse3surfaceantigens(SAGs)ofT.gondiitodesigngene-encoding amulti-epitopeandimmunogenicproteinasaserodiagnosticmarker. Materialandmethods.Themulti-epitopeantigenwasexpressedusingEscherichiacoliBL21(DE3)cells andpurifiedusingaffinitychromatography.Toevaluateacutetoxoplasmosis,95humanserawithanti-T.gondii IgG,25humanserawithoutanti-T.gondiiIgGand6serumsampleswithnosocomialinfectionswerecollected andsubmittedtoanenzyme-linkedimmunosorbentassay(ELISA)analysis.Thepotentialofpurifiedprotein asadiagnosticmarkerofT.gondiiinfectionwasalsoinvestigatedusingELISAanalysis. Results.Thewesternblotanalysisforbothproteinexpressionandpurificationconfirmedthattheproteinwas expressedandpurifiedsuccessfully.Theresultsofvalidationshowedasensitivityof72.6%andaspecificity of90.3%forrecombinantELISA. Conclusions.AlthoughthisproteinshowedpotentialfordetectingT.gondii,thesensitivityandspecificity werelowerthaninteststhatusethewholebodyoftheparasite.