title: The Toxoplasma MAG1 peptides induce sex-based humoral immune response in mice and distinguish active from chronic human infection.
abstract: To distinguish active from inactive/chronic infection in Toxoplasma gondii-seropositive individuals, we have developed an enzyme-linked immunosorbent assay (ELISA) using specific peptides derived from Toxoplasma matrix antigen MAG1. We used this assay to measure matrix specific antibodies and pilot studies with infected mice established the validity of two peptides. The immune response against MAG1 occurs in about 12 days postinfection and displays a sex difference later on in mouse model, with males producing higher antibody titers than females. Serum samples from 22 patients with clinical toxoplasmosis and from 26 patients with serological evidence of past exposure to Toxoplasma (more than one year infection history) were analyzed. Both MAG1 peptides detected antibodies significant frequently and robustly from active stage than from the chronic stage of toxoplasmosis. The results indicate that both MAG1 peptides may be used as a tool to differentiate active from inactive infection. It also may be considered in the design of potential vaccines in humans.
authors.affiliation: Stanley Division of Developmental Neurovirology, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA. jxiao4@jhmi.edu
authors.forename: Jianchun
authors.initials: J
authors.lastname: Xiao
authors.forename: Raphael P
authors.initials: RP
authors.lastname: Viscidi
authors.forename: Geetha
authors.initials: G
authors.lastname: Kannan
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Pletnikov
authors.forename: Ye
authors.initials: Y
authors.lastname: Li
authors.forename: Emily G
authors.initials: EG
authors.lastname: Severance
authors.forename: Robert H
authors.initials: RH
authors.lastname: Yolken
authors.forename: Laurence
authors.initials: L
authors.lastname: Delhaes
mesh_terms: D000595:Amino Acid Sequence; D000704:Analysis of Variance; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology; D058345:Asymptomatic Infections; D015415:Biomarkers / Q000097:blood; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology*; D012737:Sex Factors; D014122:Toxoplasma / Q000235:genetics / Q000276:immunology*; D014123:Toxoplasmosis / Q000276:immunology* / Q000469:parasitology
chemical_list: D000913:Antibodies, Protozoan; D015415:Biomarkers; D010455:Peptides; D015800:Protozoan Proteins