Recombinant expression, purification and cross-reactivity of chenopod profilin: rChe a 2 as a good marker for profilin sensitization.

Abstract

Chenopod pollen is one of the major sources of allergens in some locations in the US, southern Europe and desert countries, and pollen profilin (Che a 2) is a major allergen. Recombinant Che a 2 (rChe a 2) has been produced in Escherichia coil cells with a final yield of 25 mg/l of cell culture. The expressed protein was isolated and structurally characterized by means of mass spectrometry, Edman degradation and circular dichroism. rChe a 2 displayed a molecular mass of 13 959 Da, which agrees with that of the amino acid sequence. The N-terminal amino acid sequence indicated the correct processing of the recombinant product. The immunological analysis of rChe a 2 showed IgG- and IgE-binding capabilities equivalent to those of its natural counterpart, Che a 2, isolated from the pollen. Inhibition experiments showed high cross-reactivity degrees with different allergenic sources. Inhibition degrees of >95% and >80% were obtained for chenopod profilin and, respectively, latex and pollen extracts, whereas 10-95% of inhibition was observed for different plant-derived foods. Due to its close relation to other allergenic profilins from pollens, plant-derived foods and latex, rChe a 2 could be a useful tool in clinical trials to detect profilin-allergic patients and perhaps, depending on its clinical relevance, in specific immunotherapy of these hypersensitive individuals.