Api m 6: a new bee venom allergen.
BACKGROUND
Characterization of the primary structure of allergens is a prerequisite for the design of new diagnostic and therapeutic tools for allergic diseases.


OBJECTIVE
The purpose of this study was the identification and characterization of a low-molecular-weight, IgE-binding, bee venom (BV) allergen.


METHODS
BV proteins were separated by using size exclusion chromatography and HPLC. IgE antibody binding to purified proteins was analyzed by means of immunoblotting, and T-cell response was analyzed by means of proliferation assay. Amino acid sequence was determined with 2 approaches, namely Edman degradation and carboxy terminal analysis with mass spectrometry.


RESULTS
Api m 6, which migrated as an 8-kd band in SDS-PAGE, was frequently (42%) recognized by IgE from BV-hypersensitive patients. In addition, PBMCs from BV-hypersensitive patients, as well as from a normal control subject, proliferated in response to this allergen. Api m 6 exists as 4 isoforms of 7190, 7400, 7598, and 7808 d, respectively. Amino acid sequences obtained from HPLC-purified preparations revealed that the isoforms were constituted of a common central core of 67 residues, only differing in the amino- and carboxy-terminal ends. Api m 6 showed no significant sequence homology with known proteins.


CONCLUSIONS
We have identified and sequenced a new BV allergen that elicits a strong IgE and T-cell response in a large number of BV-hypersensitive patients. Api m 6 should be considered in the diagnostic and therapeutic approach of BV immunotherapy on the basis of peptides or recombinant proteins.
Kettner
A
A
Institute of Biochemistry, University of Lausanne, Lausanne, Switzerland.
Hughes
G J
GJ
Frutiger
S
S
Astori
M
M
Roggero
M
M
Spertini
F
F
Corradin
G
G
D000485:Allergens / Q000276:immunology / Q000302:isolation & purification*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D052179:Antigens, Plant; D001514:Bee Venoms / Q000737:chemistry / Q000276:immunology*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000097:blood / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D019476:Insect Proteins / Q000276:immunology / Q000302:isolation & purification*; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D011489:Protein Denaturation; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; D052179:Antigens, Plant; C428428:Api m 6 protein, bee; D001514:Bee Venoms; D019476:Insect Proteins; D007073:Immunoglobulin E