Isolated hevein-like domains, but not 31-kd endochitinases, are responsible for IgE-mediated in vitro and in vivo reactions in latex-fruit syndrome.
BACKGROUND
Individuals with natural rubber latex allergy often have immediate reactions to plant-derived foods and fresh fruits, such as avocado and banana. IgE of these patients has been shown to bind endochitinases containing an N-terminal hevein-like domain (HLD). However, evidence on 31-kd endochitinase-induced reactions in vivo is lacking.


OBJECTIVE
We sought to assess the clinical significance of 31-kd endochitinases and isolated HLDs in latex-fruit syndrome.


METHODS
The 31-kd endochitinases and corresponding HLDs were purified or produced from avocado, banana, latex, and wheat germ. Skin prick test reactivities against purified proteins were examined in 15 patients with natural rubber latex allergy. The binding efficiency of IgE to purified proteins was studied by using an inhibition ELISA. Experimentally resolved or modeled structures of the proteins were compared to clarify the molecular basis of clinical reactions.


RESULTS
Eleven (73%) patients had skin prick test reactions to isolated HLDs of avocado and banana, but only 1 (7%) patient reacted to their corresponding 31-kd endochitinases. HLDs from avocado and banana inhibited binding of IgE to prohevein (Hev b 6.01) in 59% and 38% of patients, respectively, whereas corresponding percentages for 31-kd endochitinases were 17% and 20%, respectively. Isolated HLDs of wheat germ agglutinin and 18-kd wheat germ agglutinin did not significantly inhibit IgE binding to hevein.


CONCLUSIONS
The isolated HLD molecules alone, but not when linked to endochitinases, seem to be responsible for IgE-mediated clinical reactions in latex-fruit syndrome. Careful selection of relevant allergens in their proper molecular form is therefore crucial in forming a reliable diagnosis of latex-fruit syndrome.
Karisola
Piia
P
Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland. karpiia@cc.jyu.fi
Kotovuori
Annika
A
Poikonen
Sanna
S
Niskanen
Einari
E
Kalkkinen
Nisse
N
Turjanmaa
Kristiina
K
Palosuo
Timo
T
Reunala
Timo
T
Alenius
Harri
H
Kulomaa
Markku S
MS
D000328:Adult; D000485:Allergens / Q000276:immunology; D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D002688:Chitinases / Q000276:immunology*; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D007840:Latex / Q000737:chemistry; D020315:Latex Hypersensitivity / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D028521:Musa / Q000737:chemistry / Q000276:immunology; D027421:Persea / Q000737:chemistry / Q000276:immunology; D037121:Plant Lectins / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D012882:Skin Tests; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000485:Allergens; D023181:Antimicrobial Cationic Peptides; D017931:DNA Primers; D007840:Latex; D037121:Plant Lectins; C045875:hevein; D007073:Immunoglobulin E; D002688:Chitinases