Cloning and expression of a major allergen from Cupressus arizonica pollen, Cup a 3, a PR-5 protein expressed under polluted environment

BACKGROUND: This paper describes the cloning and expression of the Cupressus arizonica pollen protein Cup a 3. In addition, we present its modulation under polluted environmental conditions. Species of the Cupressaceae family are important because of their high sensitization prevalence. METHODS: Cup a 3 cloning is based on the sequence of the homologous protein Jun a 3. Cup a 3 was expressed with good yield in the methylotropic yeast Pichia pastoris. RESULTS: Recombinant Cup a 3 (rCup a 3) contains 199 amino acids, 10 potential phosphorylation sites and no glycosylation sites. By immunoblot 63% of cypress allergic patients had specific immunoglobulin E antibodies against rCup a 3 (n = 104). This major allergen is homologous to members of the pathogenesis-related proteins (PR-5 group) and contributes to the overall allergenicity of C. arizonica pollen. Our results show that the increased expression of Cup a 3 is dependent on the pollution in the area where the pollen has been collected, being higher under polluted conditions. CONCLUSIONS: Cup a 3 is a PR-5 protein derived from C. arizonica pollen. The expression of the protein under polluted conditions has a direct incidence on the pollen allergenicity, as has been demonstrated by skin tests and Radioallergosorbent test inhibition.