The role of profilin and lipid transfer protein in strawberry allergy in the Mediterranean area.
BACKGROUND
In contrast to other Rosaceae fruit, only few cases of patients with adverse reactions to strawberry are listed in literature. OBJECTIVE To identify allergenic proteins in strawberry and to express and characterize recombinant strawberry lipid transfer protein (LTP; rFra a 3).


METHODS
Established apple-allergic patients were recruited on the basis of a reported allergic reaction to strawberry (n=28, confirmed by double-blind placebo-controlled food challenge in four patients) or on the basis of IgE reactivity to LTP (n=34). Sensitization to purified natural and recombinant allergens was assessed by RAST, immunoblot (inhibition) and basophil histamine release (BHR). A strawberry cDNA library was screened for genes homologous to known fruit allergens. Fra a 3 was cloned and expressed in the yeast Pichia pastoris and compared with peach and apple LTP by RAST, immunoblot-inhibition and BHR tests.


RESULTS
Genes homologous to Bet v 1, Bet v 6, profilin and LTP were identified in a strawberry cDNA library. In BHR the rFra a 3 induced histamine release at a 100-fold higher concentration than peach LTP. RAST inhibition showed high cross-reactivity to peach and apple LTP, although IgE reactivity was lower by a factor 5. On strawberry immunoblot, patients' IgE showed reactivity to a Bet v 1 homologue, profilin, LTP and high-molecular weight bands.


CONCLUSIONS
In addition to a Bet v 1 homologue, strawberry also contains IgE-binding profilin and LTP. The rFra a 3 has less allergenic potency than peach and apple LTP, and therefore is an interesting tool for future immunotherapy. Fra a 3 does not seem to be clinically relevant.
Zuidmeer
L
L
Laboratory of Allergy Research, Department of Experimental Immunology, Amsterdam Medical Centre, Amsterdam, The Netherlands. l.zuidmeer@sanquin.nl
Salentijn
E
E
Rivas
M F
MF
Mancebo
E G
EG
Asero
R
R
Matos
C I
CI
Pelgrom
K T B
KT
Gilissen
L J W J
LJ
van Ree
R
R
D000485:Allergens / Q000235:genetics / Q000276:immunology; D052179:Antigens, Plant / Q000235:genetics / Q000276:immunology; D001491:Basophils / Q000276:immunology; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology*; D015331:Cohort Studies; D003429:Cross Reactions / Q000276:immunology; D004311:Double-Blind Method; D005512:Food Hypersensitivity / Q000276:immunology*; D031985:Fragaria / Q000276:immunology*; D006636:Histamine Release / Q000276:immunology; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D007073:Immunoglobulin E / Q000276:immunology; D007558:Italy; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology*; D051304:Profilins / Q000276:immunology*; D011852:Radioallergosorbent Test / Q000379:methods; D011994:Recombinant Proteins / Q000276:immunology; D013030:Spain
D000485:Allergens; D052179:Antigens, Plant; C501561:Bet v 1 protein, Fragaria; D002352:Carrier Proteins; C514339:Fra a 3 allergen, Fragaria vesca; D010940:Plant Proteins; D051304:Profilins; D011994:Recombinant Proteins; C511920:lipid transfer proteins, plant; D007073:Immunoglobulin E