Peach profilin: cloning, heterologous expression and cross-reactivity with Bet v 2.
BACKGROUND
Peach is among the main foods causing allergic reactions in the Mediterranean adult population. Only a single peach allergen, named Pru p 3, has been characterized. However, a potential role of profilin has also been suggested in grass pollen-associated allergy to peach.


METHODS
Complementary DNA clones for two different peach profilin isoforms were obtained by reverse transcriptase polymerase chain reaction using non-degenerated primers. Expression of recombinant peach profilin was performed in Escherichia coli, and confirmed using rabbit polyclonal antibodies to sunflower pollen profilin. Twenty-nine individual sera from patients with peach allergy proved by double-blind, placebo-controlled food challenges (DBPCFC), either with (n = 15) or without (n = 14) specific IgE to Bet v 2, were used in immunodetection assays to test recombinant peach profilin reactivity.


RESULTS
Each peach profilin cDNA included an open reading frame coding for a 131 amino acid protein. The peach profilin isoforms, designated Pru p 4.01 and Pru p 4.02, showed 80% of amino acid sequence identity, and were very similar (>70% identity) to allergenic profilins from plant foods and pollens. Recombinant Pru p 4.01 was expressed in E. coli as a nonfusion protein, displaying the expected molecular size and reacting with anti-profilin antibodies. rPru p 4.01 was recognized by all sera (15 of 15) with specific IgE to Bet v 2, whereas no sera (zero of 14) without IgE to this birch allergen reacted with rPru p 4.01.


CONCLUSIONS
Peach profilin Pru p 4 is very closed to other allergenic profilins from plant foods and pollens. A complete correlation between reactivity to rPru p 4 and rBet v 2 has been found in sera from peach allergic patients.
Rodríguez-Perez
R
R
Unidad de Alergia, Fundación Hospital Alcorcon, Madrid, Spain; Unidad de Bioquímica, Departamento de Biotecnología, E.T.S. Ingenieros Agrónomos, Madrid, Spain.
Fernández-Rivas
M
M
González-Mancebo
E
E
Sánchez-Monge
R
R
Díaz-Perales
A
A
Salcedo
G
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000096:biosynthesis / Q000276:immunology* / Q000302:isolation & purification; D000918:Antibody Specificity / Q000276:immunology; D015478:Antigens, Heterophile / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D001483:Base Sequence; D002648:Child; D003001:Cloning, Molecular; D003285:Contractile Proteins; D003429:Cross Reactions / Q000276:immunology; D018076:DNA, Complementary / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D008840:Microfilament Proteins / Q000096:biosynthesis / Q000276:immunology* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011058:Pollen / Q000276:immunology; D051304:Profilins; D027861:Prunus / Q000276:immunology*; D020539:Sequence Analysis, Protein; D013030:Spain; D014581:Urticaria / Q000276:immunology / Q000378:metabolism
D000485:Allergens; D015478:Antigens, Heterophile; D003285:Contractile Proteins; D018076:DNA, Complementary; D008840:Microfilament Proteins; D051304:Profilins; D007073:Immunoglobulin E