title: Identification of immunodominant antigens for the laboratory diagnosis of toxocariasis.
abstract: OBJECTIVE
  To identify immunodominant antigens of Toxocara canis recognised by Toxocara-infected sera as recombinant reagents for immunodiagnosis of toxocariasis.
  
  
  METHODS
  Pooled sera from human cases of toxocariasis were used to identify immunodominant antigens by immunoscreening a T. canis larval expression cDNA library. The positive clones were sequenced to reveal the identity of the antigens. The recombinant proteins were expressed in E. coli and then used to confirm their immunoreaction with sera of humans with toxocariasis. Two chosen antigens were also used to differentiate Toxocara infection from other helminth infections in mice.
  
  
  RESULTS
  Eleven antigens with immunodiagnostic potential were identified, including two C-type lectins (CTLs) that reacted strongly with the Toxocara-positive serum pool. The first CTL (Tc-CTL-1) is the same as TES-32, previously identified as a major immunodominant component of TES; the second CTL (Tc-CTL-2) is a novel C-type lectin sharing 83% amino acid sequence identity within the functional domain of Tc-CTL-1. The E. coli-expressed recombinant Tc-CTL-1 was strongly recognised by the Toxocara-positive serum pool or sera from animals experimentally infected with T. canis. Reactivity with recombinant Tc-CTL-1 was higher when the unreduced protein was used in an enzyme-linked immunosorbent assay (ELISA), dot-blot assay or Western blot test compared to the protein under reduced condition. Both recombinant Tc-CTL-1- and Tc-CTL-2-based ELISAs were able to differentiate T. canis infection from other helminth infections in experimentally infected mice.
  
  
  CONCLUSIONS
  Both Tc-CTL-1 and Tc-CTL-2 were able to differentiate Toxocara infection from other helminth infections and could potentially be used as sensitive and specific immunodiagnostic antigens.
authors.affiliation: Baylor College of Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, TX, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhan
authors.affiliation: Whitman Walker Health, Washington, DC, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Ajmera
authors.affiliation: Departamento de Parasitologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Stefan Michael
authors.initials: SM
authors.lastname: Geiger
authors.affiliation: Departamento de Parasitologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Marco Túlio Porto
authors.initials: MT
authors.lastname: Gonçalves
authors.affiliation: Baylor College of Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, TX, USA.
authors.forename: Zhuyun
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Baylor College of Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, TX, USA.
authors.forename: Junfei
authors.initials: J
authors.lastname: Wei
authors.affiliation: Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Patricia P
authors.initials: PP
authors.lastname: Wilkins
authors.affiliation: Departamento de Parasitologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Fujiwara
authors.affiliation: Departamento de Parasitologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Pedro Henrique
authors.initials: PH
authors.lastname: Gazzinelli-Guimaraes
authors.affiliation: Baylor College of Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, TX, USA.
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Bottazzi
authors.affiliation: Baylor College of Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, TX, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Hotez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000947:Antigens, Helminth / Q000276:immunology*; D015153:Blotting, Western; D019411:Clinical Laboratory Techniques; D018076:DNA, Complementary; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D006373:Helminthiasis / Q000175:diagnosis / Q000276:immunology; D006801:Humans; D016056:Immunodominant Epitopes; D007814:Larva; D037102:Lectins / Q000276:immunology; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000276:immunology; D017166:Toxocara canis / Q000276:immunology*; D014120:Toxocariasis / Q000175:diagnosis* / Q000276:immunology
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D018076:DNA, Complementary; D016056:Immunodominant Epitopes; D037102:Lectins; D011994:Recombinant Proteins
keywords: Tc-CTL-1; Tc-CTL-2; immunodiagnosis; recombinant protein; toxocariasis