Identification of Plantago lanceolata pollen allergens using an immunoproteomic approach.

BACKGROUND Airborne Plantago pollen triggers respiratory allergies in Mediterranean countries. OBJECTIVES We aimed to study sensitization in patients with seasonal respiratory allergy and identify proteins of Plantago lanceolata pollen that could be responsible for hypersensitivity reactions in sensitized patients. We also determined the airborne pollen concentration of Plantago species from 2004 to 2011. METHODS IgE-binding proteins were analyzed and characterized using 1D and 2D gel electrophoresis and immunoblotting with sera from individuals sensitized to P lanceolata pollen extracts, mass spectrometry analysis, and protein data mining. We used aerobiological methods to study airborne pollen. RESULTS P lanceolata pollen accounts for 3% of the annual pollen spectrum in the air of Porto. Of a total of 372 patients, 115 (31%) showed specific IgE levels to P lanceolata pollen extracts. All sera from P lanceolata-allergic patients recognized 8 prominent groups of IgE-reactive allergens. Separation of proteins using 2D gel electrophoresis followed by identification with mass spectrometry revealed the presence of other IgE-reactive components that could be involved in sensitization. CONCLUSIONS We detected proteins in P lanceolata pollen extracts that, to our knowledge, have not yet been studied and could worsen sensitization to this weed pollen species. The proteins identified were involved in a variety of cellular functions. By applying 2D electrophoresis and immunoblotting with a pool of 2 sera from different P lanceolata-allergic patients, we obtained a more detailed characterization of the P lanceolata allergen profile.