title: Analysis of clonal type-specific antibody reactions in Toxoplasma gondii seropositive humans from Germany by peptide-microarray.
abstract: BACKGROUND
  Different clonal types of Toxoplasma gondii are thought to be associated with distinct clinical manifestations of infections. Serotyping is a novel technique which may allow to determine the clonal type of T. gondii humans are infected with and to extend typing studies to larger populations which include infected but non-diseased individuals.
  
  
  METHODS
  A peptide-microarray test for T. gondii serotyping was established with 54 previously published synthetic peptides, which mimic clonal type-specific epitopes. The test was applied to human sera (n = 174) collected from individuals with an acute T. gondii infection (n = 21), a latent T. gondii infection (n = 53) and from T. gondii-seropositive forest workers (n = 100).
  
  
  RESULTS
  The majority (n = 124; 71%) of all T. gondii seropositive human sera showed reactions against synthetic peptides with sequences specific for clonal type II (type II peptides). Type I and type III peptides were recognized by 42% (n = 73) or 16% (n = 28) of the human sera, respectively, while type II-III, type I-III or type I-II peptides were recognized by 49% (n = 85), 36% (n = 62) or 14% (n = 25) of the sera, respectively. Highest reaction intensities were observed with synthetic peptides mimicking type II-specific epitopes. A proportion of the sera (n = 22; 13%) showed no reaction with type-specific peptides. Individuals with acute toxoplasmosis reacted with a statistically significantly higher number of peptides as compared to individuals with latent T. gondii infection or seropositive forest workers.
  
  
  CONCLUSIONS
  Type II-specific reactions were overrepresented and higher in intensity in the study population, which was in accord with genotyping studies on T. gondii oocysts previously conducted in the same area. There were also individuals with type I- or type III-specific reactions. Well-characterized reference sera and further specific peptide markers are needed to establish and to perform future serotyping approaches with higher resolution.
authors.affiliation: Friedrich-Loeffler-Institut, Wusterhausen, Germany. pavlo.maksimov@fli.bund.de
authors.forename: Pavlo
authors.initials: P
authors.lastname: Maksimov
authors.forename: Johannes
authors.initials: J
authors.lastname: Zerweck
authors.forename: Aline
authors.initials: A
authors.lastname: Maksimov
authors.forename: Andrea
authors.initials: A
authors.lastname: Hotop
authors.forename: Uwe
authors.initials: U
authors.lastname: Gross
authors.forename: Katrin
authors.initials: K
authors.lastname: Spekker
authors.forename: Walter
authors.initials: W
authors.lastname: Däubener
authors.forename: Sandra
authors.initials: S
authors.lastname: Werdermann
authors.forename: Olaf
authors.initials: O
authors.lastname: Niederstrasser
authors.forename: Eckhardt
authors.initials: E
authors.lastname: Petri
authors.forename: Marc
authors.initials: M
authors.lastname: Mertens
authors.forename: Rainer G
authors.initials: RG
authors.lastname: Ulrich
authors.forename: Franz J
authors.initials: FJ
authors.lastname: Conraths
authors.forename: Gereon
authors.initials: G
authors.lastname: Schares
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology; D005858:Germany; D006801:Humans; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology*; D040081:Protein Array Analysis; D012703:Serotyping; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D010455:Peptides