Analysis of sequential immunoglobulin E-binding epitope of Japanese cedar pollen allergen (Cry j 2) in humans, monkeys and mice.
BACKGROUND
Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported to occur naturally in Japanese monkeys (Macaca fuscata) as well as in humans. Most human patients and monkeys with pollinosis have specific IgE for Cry j 2, a major allergen of CJ pollen.


OBJECTIVE
The main purpose of this study was to identify IgE B cell epitopes of Cry j 2 using a synthetic peptide in humans, monkeys and mice.


METHODS
We synthesized 38 overlapping peptides that span the entire length of Cry j 2. We examined the B cell epitopes of Cry j 2 that are recognized by IgE in the sera of human patients and monkeys with pollinosis and immunized mice using synthetic peptides of Cry j 2. We also examined the reaction of Cry j 2-specific mouse monoclonal IgG antibodies to the peptides. Furthermore, we conducted a histamine release assay with leucocytes from a pollinosis patient using human serum albumin (HSA) conjugated with the peptides as a B cell epitope.


RESULTS
We found that 16 of the 20 pollinosis patients who had specific IgE to Cry j 2 also exhibited IgE reaction with some Cry j 2 peptides. Of these 16 patients, 10 exhibited IgE reaction with Cry j 2 peptide no. 13 (121GQCKWVNGREICNDRDRPTA140). Five of the seven monkeys with CJ pollinosis exhibited a reaction with peptide no. 13. Furthermore, IgE in mice immunized with Cry j 2 and two mouse monoclonal IgG antibodies reacted with peptide no. 13. Peptide no. 13-conjugated HSA showed the release of histamine from basophils. Furthermore, to determine the minimum epitope in peptide no. 13, we conducted an enzyme-linked immunosorbent assay inhibition test. The core of the epitope in humans, monkeys and mice was 124KWVNGREI131.


CONCLUSIONS
We found that 124KWVNGREI131 is an important B cell epitope recognized by IgE in humans, monkeys and mice.
Tamura
Y
Y
Department of Immunology, National Institute of Infectious Diseases, Tokyo, Japan.
Kawaguchi
J
J
Serizawa
N
N
Hirahara
K
K
Shiraishi
A
A
Nigi
H
H
Taniguchi
Y
Y
Toda
M
M
Inouye
S
S
Takemori
T
T
Sakaguchi
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000918:Antibody Specificity; D018985:Epitopes, B-Lymphocyte / Q000378:metabolism*; D005260:Female; D006636:Histamine Release / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism*; D008251:Macaca / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D010446:Peptide Fragments / Q000276:immunology; D010940:Plant Proteins / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*; D012882:Skin Tests / Q000379:methods; D013045:Species Specificity
D000911:Antibodies, Monoclonal; C065291:Cry j II protein, Cryptomeria japonica; D018985:Epitopes, B-Lymphocyte; D010446:Peptide Fragments; D010940:Plant Proteins; D007073:Immunoglobulin E