title: P35 and P22 Toxoplasma gondii antigens abbreviate regions to diagnose acquired toxoplasmosis during pregnancy: toward single-sample assays.
abstract: BACKGROUND
  P35 and P22 Toxoplasma gondii proteins are recognized by specific IgG at the early infection stage, making them ideal for acute toxoplasmosis pregnancy control. Both proteins have been studied to discriminate between acute and chronic toxoplasmosis. However, results were hardly comparable because different protein obtainment procedures led to different antigens, the reference panels used were not optimally typified, and avidity tests were either not performed or narrowly examined.
  
  
  METHODS
  We bioinformatically predicted P35 and P22 regions with the highest density of epitopes, and expressed them in pET32/BL21DE3 alternative expression system, obtaining the soluble proteins rP35a and rP22a. We assessed their diagnostic performance using pregnant woman serum samples typified as: not infected, NI (IgG-, IgM-), typical-chronic, TC (IgM-, IgG+), presumably acute, A (IgG+, IgM+, low-avidity IgG), and recently chronic, RC (IgG+, IgM+, high-avidity IgG).
  
  
  RESULTS
  rP35a performed better than rP22a to differentiate A from RC, the areas under the curve (AUC) being 0.911 and 0.818, respectively. They, however, performed similarly to differentiate A from TC+RC (AUC: 0.915 and 0.907, respectively). rP35a and rP22a evaluation by avidity ELISA to discriminate A from RC rendered AUC values of 0.974 and 0.921, respectively. The indirect ELISA and avidity ELISA results analyzed in tandem were consistent with those obtained using commercial kits.
  
  
  CONCLUSIONS
  rP35a and rP22a features suggest that, with complementary use, they could replace parasite lysate for toxoplasmosis infection screening and for acute toxoplasmosis diagnosis. Our proposal should be validated by a longitudinal study and may lead to a reliable toxoplasmosis pregnancy control, performing tests in only one serum sample.
authors.forename: Juan G
authors.initials: JG
authors.lastname: Costa
authors.forename: Leandro E
authors.initials: LE
authors.lastname: Peretti
authors.forename: Valeria S
authors.initials: VS
authors.lastname: García
authors.forename: Luz
authors.initials: L
authors.lastname: Peverengo
authors.forename: Verónica D G
authors.initials: VD
authors.lastname: González
authors.forename: Luis M
authors.initials: LM
authors.lastname: Gugliotta
authors.forename: Maria L
authors.initials: ML
authors.lastname: Dalla Fontana
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Lagier
authors.forename: Iván S
authors.initials: IS
authors.lastname: Marcipar
mesh_terms: D000953:Antigens, Protozoan / Q000097:blood* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000175:diagnosis*; D015800:Protozoan Proteins / Q000097:blood* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014122:Toxoplasma / Q000472:pathogenicity; D014123:Toxoplasmosis / Q000175:diagnosis*
chemical_list: D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C067547:surface antigen P22, Toxoplasma