Analysis of IgE binding proteins of Celtis tala pollen

Celtis tala is a tree, widely distributed in Argentina. Its significance as a source of allergic sensitisation is still unclear. Our aim was to partially characterise the IgE binding proteins of C. tala pollen. Skin prick tests using C. tala pollen extract were carried out in 25 patients with respiratory allergy. Celtis tala extract elicited positive skin reactions in five patients. Sensitised patients showed increased specific IgE levels to C. tala by immunodot. Immunoblotting assay demonstrated IgE binding to proteins of 50 kDa and 55 kDa. Celtis tala pollen extract is allergenically potent requiring approximately 50 ng of self-protein for 50% inhibition of IgE binding in enzyme_linked immunosorbent assay (ELISA) inhibition, whereas no cross-inhibition was detected with other types of pollen widely distributed in Argentina (Helianthus annuus and Prosopis spp.). Thus, these results taken together indicate that proteins of 50 kDa and 55 kDa may be considered as specific allergens of C. tala pollen.