Identification, characterization and expression of Toxocara canis nematode polyprotein allergen TBA-1.
We have cloned the cDNA of TBA-1, the Nematode polyprotein allergen (NPA) of Toxocara canis and found it to be most similar to ABA-1, the Ascaris NPA, on the basis of amino acid sequence. We could study the antigenic properties of an E-coli synthesized fusion protein prepared with the cloned gene since no glycosylation site was expected from the deduced amino acid sequence. Although no IgE responses to TBA-1 were detected, recombinant TBA-1 was differently recognized by serum IgG antibodies when the recombinant TBA-1 was directly adsorbed vs when immobilized via a streptavidin linkage on polystyrene microtitre wells. One group of sera recognized TBA-1 directly immobilized while the second only recognized TBA-1 immobilized via streptavidin linkage. The former were from rodents immunized with a Toxocara sp. adult worm extract while the latter were obtained from rodents infected with T. canis larva or immunized with a Anisakis simplex L3 larval extract. These observations suggest that the two in vivo forms of TBA-1 are expressed, but during different stages of the parasite's life cycle.
Department of Parasitology, School of Medicine, Fukuoka University, 7-45-1, Nanakuma, Jounan-ku, Fukuoka City 814-0180, Japan.
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Yahiro
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Cain
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Butler
D000485:Allergens / Q000235:genetics* / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004285:Dogs; D005260:Female; D005822:Genetic Vectors; D015698:Genomic Library; D015801:Helminth Proteins / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000276:immunology; D016415:Sequence Alignment; D017166:Toxocara canis / Q000235:genetics / Q000276:immunology*; D014162:Transfection
D000485:Allergens; D000947:Antigens, Helminth; D018076:DNA, Complementary; D015801:Helminth Proteins; D011993:Recombinant Fusion Proteins