Identification of major allergens in watermelon.
BACKGROUND
Watermelon is a worldwide consumed Cucurbitaceae fruit that can elicit allergic reactions. However, the major allergens of watermelon are not known. The aim of this study is to identify and characterize major allergens in watermelon.


METHODS
Twenty-three patients allergic to watermelon took part in the study. The diagnosis was based on a history of symptoms and positive skin prick-prick tests to watermelon, confirmed by positive open oral challenge testing to watermelon pulp. Allergenic components were detected by SDS-PAGE and immunoblotting. Molecular characterization of IgE-binding bands was performed by N-terminal amino acid sequencing and mass spectrometry. Allergens were purified combining several chromatographic steps.


RESULTS
Several IgE binding bands (8-120 kDa) were detected in watermelon extract. Three major allergens were identified as malate dehydrogenase (36 kDa), triose phosphate isomerase (28 kDa) and profilin (13 kDa). Purified allergens individually inhibited IgE binding to the whole watermelon extract.


CONCLUSIONS
All in all these results indicate that malate dehydrogenase, triose phosphate isomerase and profilin are major allergens involved in watermelon allergy.
Pastor
Carlos
C
Departamento de Inmunología, Fundación Jiménez Díaz, ES-28040 Madrid, Spain.
Cuesta-Herranz
Javier
J
Cases
Barbara
B
Pérez-Gordo
Marina
M
Figueredo
Elena
E
de las Heras
Manuel
M
Vivanco
Fernando
F
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology* / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D029773:Citrullus / Q000276:immunology*; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008291:Malate Dehydrogenase / Q000276:immunology* / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D051304:Profilins / Q000276:immunology* / Q000302:isolation & purification; D012882:Skin Tests; D014305:Triose-Phosphate Isomerase / Q000276:immunology* / Q000302:isolation & purification; D055815:Young Adult
D000485:Allergens; D051304:Profilins; D007073:Immunoglobulin E; D008291:Malate Dehydrogenase; D014305:Triose-Phosphate Isomerase