Abstract
To characterize the allergens of Blomia tropicalis, a cDNA library was constructed and screened with allergic sera from asthmatic patients. One clone, Bt6, was subcloned and sequenced. The nucleotide sequence of 934 bp length shows a 390-bp reading frame which encodes a 130-amino acid protein with a MW 14.8 kD. No potential glycosylation site was found in the predicted protein. The inferred amino acid sequence has no homology to known allergens. It has a cytosolic fatty acid-binding protein (FABP) signature at 5-22 amino acid residues, 42.3% identity with the Sm14-FABP of Schistosoma mansoni and 36% identity with FABPs from rat, mouse, bovine and human. The protein was expressed as a GST fusion protein and the purified GST-Bt6 used for dot blot, RAST and RAST inhibition assays. The frequency of IgE binding of allergic sera to Bt6 was low (11%) and usually weak. One positive serum did, however, show strong reactivity by RAST and dot blot and Bt6 could inhibit 60% of the IgE binding of this serum to the B. tropicalis extract. These data show that Bt6 encodes a mite FABP with allergenic properties, which are pronounced in some atopic subjects.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Allergens / chemistry
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Allergens / genetics*
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Allergens / isolation & purification
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Allergens / metabolism
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Amino Acid Sequence
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Animals
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Antigens, Plant
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Base Sequence
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Binding Sites, Antibody*
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Carrier Proteins / chemistry*
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Carrier Proteins / genetics
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Carrier Proteins / immunology
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Cloning, Molecular
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Fatty Acid-Binding Protein 7
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Fatty Acid-Binding Proteins
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Fatty Acids / metabolism
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Glutathione Transferase / genetics
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Humans
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Immunoglobulin E / blood
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Immunoglobulin E / metabolism*
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Mites / immunology*
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Molecular Sequence Data
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Myelin P2 Protein / chemistry*
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Myelin P2 Protein / genetics
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Myelin P2 Protein / immunology
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Neoplasm Proteins*
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Nerve Tissue Proteins*
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Radioallergosorbent Test
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Recombinant Proteins / immunology*
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Recombinant Proteins / metabolism
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Sequence Homology, Amino Acid
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Thrombin
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Tumor Suppressor Proteins*
Substances
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Allergens
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Antigens, Plant
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Carrier Proteins
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FABP7 protein, human
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Fabp7 protein, rat
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Fatty Acid-Binding Protein 7
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Fatty Acid-Binding Proteins
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Fatty Acids
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Myelin P2 Protein
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Neoplasm Proteins
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Nerve Tissue Proteins
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Recombinant Proteins
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Tumor Suppressor Proteins
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allergen Bt6, Blomia tropicalis
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Immunoglobulin E
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Glutathione Transferase
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Thrombin