title: Identification of Toxoplasma gondii in-vivo induced antigens by cDNA library immunoscreening with chronic toxoplasmosis sera.
abstract: Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. Chronically-infected individuals with a compromised immune system are at risk for reactivation of the disease. In-vivo induced antigen technology (IVIAT) is a promising method for the identification of antigens expressed in-vivo. The aim of the present study was to apply IVIAT to identify antigens which are expressed in-vivo during T. gondii infection using sera from individuals with chronic toxoplasmosis. Forty serum samples were pooled, pre-adsorped against three different preparations of antigens, from each in-vitro grown T. gondii and Escherichia coli XLBlue MRF', and then used to screen a T. gondii cDNA expression library. Sequencing of DNA inserts from positive clones showed eight open reading frames with high homology to T. gondii genes. Expression analysis using quantitative real-time PCR showed that SAG1-related sequence 3 (SRS3) and two hypothetical genes were up-regulated in-vivo relative to their expression levels in-vitro. These three proteins also showed high sensitivity and specificity when tested with individual serum samples. Five other proteins namely M16 domain peptidase, microneme protein, elongation factor 1-alpha, pre-mRNA-splicing factor and small nuclear ribonucleoprotein F had lower RNA expression in-vivo as compared to in-vitro. SRS3 and the two hypothetical proteins warrant further investigation into their roles in the pathogenesis of toxoplasmosis.
authors.affiliation: Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), 11800 Gelugor, Penang, Malaysia.
authors.forename: Atefeh
authors.initials: A
authors.lastname: Amerizadeh
authors.forename: Zulkarnain Md
authors.initials: ZM
authors.lastname: Idris
authors.forename: Boon Yin
authors.initials: BY
authors.lastname: Khoo
authors.forename: Dupadahalli
authors.initials: D
authors.lastname: Kotresha
authors.forename: Muhammad Hafiznur
authors.initials: MH
authors.lastname: Yunus
authors.forename: Izzati Zahidah Abdul
authors.initials: IZ
authors.lastname: Karim
authors.forename: Geita
authors.initials: G
authors.lastname: Saadatnia
authors.forename: Ai Ying
authors.initials: AY
authors.lastname: Teh
authors.forename: Rahmah
authors.initials: R
authors.lastname: Noordin
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D002908:Chronic Disease; D004926:Escherichia coli; D015870:Gene Expression; D020869:Gene Expression Profiling; D015723:Gene Library; D006801:Humans; D051379:Mice; D016366:Open Reading Frames; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014122:Toxoplasma / Q000235:genetics / Q000276:immunology*; D014123:Toxoplasmosis / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan