Discovery of new Toxoplasma gondii antigenic proteins using a high throughput protein microarray approach screening sera of murine model infected orally with oocysts and tissue cysts

Abstract

BackgroundToxoplasma gondii is an obligate intracellular protozoan parasite that causes congenital toxoplasmosis, as well as other serious clinical presentations in immune compromised humans. The parasite has also been recently linked to behavioral diseases in humans and other mammalian hosts. New antigens are being evaluated to develop a diagnostic kit for the diagnosis of acute infection or a protective vaccine.MethodsIn this study, we have focused on the discovery of new antigenic proteins from T. gondii genomic data using a high throughput protein microarray screening. To date, microarrays containing > 2870 candidate exon products of T. gondii have been probed with sera collected from patients with toxoplasmosis. Here, the protein microarrays are probed with well-characterized serum samples from animal models administered orally with oocysts or tissue cysts. The aim was to discover the antigens that overlap in the mouse profile with human antibody profiles published previously. For this, a reactive antigen list of 240 antigens recognized by murine IgG and IgM was identified using pooled sera from orally infected mice.ResultsAnalyses of screening data have identified plenty of antigens and showed strong immunogenicity in both mouse and human antibody profiles. Among them, ROP1, GRA2, GRA3, GRA4, GRA5, GRA6, GRA7, GRA8, GRA14, MIC1, MIC2 and MAG1 have shown strong immunogenicity and used as antigen in development of vaccines or serological diagnostic assays in previous studies.ConclusionIn addition to the above findings, ROP6, MIC12, SRS29A and SRS13 have shown strong immunogenicity but have not been tested in development of a diagnostic assay or a vaccine model yet.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-2934-1) contains supplementary material, which is available to authorized users.

Investigation of the role of stray cats for transmission of toxoplasmosis to humans and animals living in İzmir, Turkey

“…Thereafter, tap water was discarded without loss of feces and sucrose solution (53 g sucrose, 100 mL water) was added up to the top level of feces and emulsified by sterile tongue depressor. Next, the mixture was filtered through 2 layers of gauze and centrifuged at 400×g for 10 minutes [20][21][22]. Thereafter, supernatant was collected from the top of each tube using a sterile Pasteur pipette and the presence of oocysts was investigated using a phase contrast microscope (Nikon, Melville, USA).…”

Development of a hexavalent recombinant protein vaccine adjuvanted with Montanide ISA 50 V and determination of its protective efficacy against acute toxoplasmosis

“…One of the most important issues during a recombinant protein vaccine development is the selection of the vaccine candidate antigen(s) [5]. Antigens to be used in vaccine formulations against toxoplasmosis should actively induced strong immune response, produce long-lasting immunity, and be antigenic in each stage of the parasite [6]. In our study group's previous studies, we used protein microarray containing 2870 candidate exon products of T. gondii to screen well-characterized sera from acute and chronic toxoplasmosis human cases and murine model infected orally with oocysts or tissue cysts.…”

A brain cyst load-associated antigen is a Toxoplasma gondii biomarker for serodetection of persistent parasites and chronic infection

“…We have only detected anti-BCLA IgG isotype and this, exclusively over the course of chronic infection. Contrasting with the IgM response reported in mice 10 days after oral ingestion of cysts [ 30 ], the IgG isotype restriction of anti-BCLA antibodies reinforces the view of BCLA as a timely marker for the latent stage of T. gondii human and animal infections. Therefore, rBCLA fills the criteria required for a serologic predictive marker of cystogenic potential in clinical isolates.…”