Recombinant lipid transfer protein Cor a 8 from hazelnut: a new tool for in vitro diagnosis of potentially severe hazelnut allergy.
BACKGROUND
Cor a 1.04 has been identified as the major hazelnut allergen in 65 European patients with positive double-blind, placebo-controlled food challenge results to hazelnut. Recently, the 11S globulin Cor a 9 was shown to be a pollen-independent hazelnut allergen in the United States, whereas preliminary data suggest the lipid transfer protein (LTP) as an important birch pollen-unrelated hazelnut allergen in Europe.


OBJECTIVE
We sought to recruit a group of European patients allergic to hazelnut without birch pollen allergy and to identify and clone the major food allergen(s) in this study population.


METHODS
We recruited 26 such Spanish patients, including 10 patients with anaphylaxis. IgE immunoblotting was performed with hazelnut extract. Hazelnut LTP Cor a 8 was cloned by using a PCR strategy, purified, and subjected to IgE immunoblotting. Recombinant Cor a 8, rCor a 1.0401, and rCor a 2 (profilin) were further investigated by means of enzyme allergosorbent test. Immunoblot inhibition experiments were used to compare the immunologic properties of natural and recombinant LTP.


RESULTS
A 9-kd major allergen was identified in hazelnut extract. Cloning, sequencing, heterologous expression, and inhibition experiments identified it as an LTP. The prevalence of specific IgE antibody reactivity to LTP was 62% in hazelnut extract and 77% when recombinant LTP was tested by means of immunoblotting. IgE immunoblot inhibition with hazelnut extract showed that natural Cor a 8 and rCor a 8 shared identical epitopes. Only one patient had positive reactivity to Cor a 1.04, and no patients had positive reactivity to Cor a 2. Two sera bound to high-molecular-weight allergens. The LTP was denominated as Cor a 8 and submitted to the allergen database of the World Health Organization/International Union of Immunological Societies Allergen Nomenclature Subcommittee.


CONCLUSIONS
Cor a 8 is a relevant allergen for a majority of Spanish patients with hazelnut allergy that can cause severe allergic reactions.
Schocker
Frauke
F
Forschungszentrum Borstel, Division of Biochemical and Molecular Allergology, Borstel, Germany.
Lüttkopf
Dirk
D
Scheurer
Stephan
S
Petersen
Arnd
A
Cisteró-Bahima
Anna
A
Enrique
Ernesto
E
San Miguel-Moncín
Mar
M
Akkerdaas
Jaap
J
van Ree
Ronald
R
Vieths
Stefan
S
Becker
Wolf-Meinhard
WM
D000328:Adult; D000485:Allergens / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics; D002648:Child; D002852:Chromatography, Ion Exchange; D003001:Cloning, Molecular; D031211:Corylus / Q000009:adverse effects* / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D021184:Nut Hypersensitivity / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology; D010940:Plant Proteins; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins
D000485:Allergens; D052179:Antigens, Plant; D002352:Carrier Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; C511920:lipid transfer proteins, plant; D007073:Immunoglobulin E