Abstract for PubMed entry 15208604

Title		Profilin (Che a 2) and polcalcin (Che a 3) are relevant allergens of Chenopodium album pollen: isolation, amino acid sequences, and immunologic properties.
Authors		R.Barderas, M.Villalba, C.Y.Pascual, E.Batanero, R.Rodríguez.
Ref.		J Allergy Clin Immunol, 2004, 113, 1192-1198.
PubMed id		15208604
Abstract
BACKGROUND: Little is known about the molecular properties of chenopod allergens. Recently, profilin and 2 EF-hand calcium-binding protein (polcalcin) have been shown to play a role in chenopod pollinosis. OBJECTIVE: We sought to analyze these panallergens in chenopod pollen and to evaluate their involvement in the allergy to this biologic source. METHODS: Profilin and polcalcin were purified to homogeneity and characterized by using spectrometric and chemical methods. Immunologic analyses were performed by means of immunoblotting, ELISA, and competitive inhibition assays with olive profilin- and polcalcin-specific rabbit polyclonal antibodies and sera from patients with chenopod allergy. cDNAs encoding these proteins were cloned by means of PCR and sequenced. RESULTS: Purified Che a 2 (profilin) and Che a 3 (polcalcin) exhibited prevalences of 55% and 46%, respectively, in patients (n=104) hypersensitive to chenopod pollen. Both purified allergens individually inhibited the IgE binding to the whole pollen extract and showed strong cross-reactivity with the corresponding olive pollen profilin (Ole e 2) and polcalcin (Ole e 3). Chenopod profilin consists of a 131-amino-acid chain that displays identities of approximately 75% and 82% with pollen and food profilins, respectively. Che a 3 (86 amino acids) displays similarity (65% to 82% identity) with polcalcins from pollens of olive, birch, alder, rapeseed, and timothy. CONCLUSION: Profilin and polcalcin are relevant panallergens in chenopod pollen and good candidates to be involved in IgE cross-reactivity with other pollen sources, thus explaining the highly frequent polysensitization of patients allergic to chenopod.