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

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.