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Identification of immunodominant antigens for the laboratory diagnosis of toxocariasis
Author(s) -
Zhan Bin,
Ajmera Ravi,
Geiger Stefan Michael,
Gonçalves Marco Túlio Porto,
Liu Zhuyun,
Wei Junfei,
Wilkins Patricia P.,
Fujiwara Ricardo,
GazzinelliGuimaraes Pedro Henrique,
Bottazzi Maria Elena,
Hotez Peter
Publication year - 2015
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/tmi.12607
Subject(s) - ctl* , immunoscreening , toxocara canis , toxocariasis , biology , antigen , recombinant dna , virology , antigenicity , immunodominance , microbiology and biotechnology , immunology , epitope , helminths , complementary dna , cdna library , genetics , gene , cd8
Objectives 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 ( CTL s) 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 ELISA s 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.