Identification and Characterization of Che a 1 Allergen from <i>Chenopodium album</i> Pollen

<i>Background:</i> Pollinosis to <i>Chenopodium album</i> has been reported, but no data are available on its allergenic proteins. <i>Methods:</i> An allergen from <i>C. album</i> pollen has been isolated by means of gel permeation and reverse-phase high-performance liquid chromatography. Molecular characterization was achieved by concanavalin A reaction, mass spectrometry, Edman degradation and cDNA sequence. Antigenic analyses were performed by immunoblotting, ELISA, and ELISA inhibition, using sera from allergic patients, two Ole e 1-specific monoclonal antibodies and an Ole e 1-specific polyclonal antiserum. <i>Results:</i> The isolated allergen, Che a 1, is a glycoprotein of molecular mass 17.088 kD and 143 amino acid residues, whose sequence exhibits 27–45% identity with known members of the Ole e 1-like protein family. 77% of sera from patients allergic to chenopod pollen were reactive to Che a 1. No correlation was found between the IgE reactivities to Che a 1 and Ole e 1, the major allergens from olive pollen, and both allergens display low, although detectable, IgE and IgG cross-reactivities. <i>Conclusions:</i> Che a 1, a relevant allergen from chenopod pollen, is structurally related to the Ole e 1-like protein family, but exhibits significant differences on its polypeptide sequence that could explain its different antigenic behavior and limited cross-reactivity.