Background and Results
The major house dust mite allergen Der p 2 was expressed as a recombinant mature protein in the baker's yeast Saccharomyces cerevisiae. The yeast produces the protein fused to the invertase signal peptide, leading to the secretion of Der p 2 as a soluble protein into the culture medium. The signal peptide is hereby cleaved off, resulting in a mature allergen. In this system Der p 2 was produced in 7.6 (± 2.9) mg/L growth culture. Purification of the recombinant allergen was achieved by a single gel filtration step, resulting in a purity ≥ 95%. The yeast-derived Der p 2 was almost indistinguishable from natural Der p 2 with respect to IgE-reactivity and binding to the majority of Der p 2 specific MoAbs — as was shown in RAST analysis (n = 168) and a sandwich ELISA and RIA analysis, respectively. Recombinant and natural Der p 2 also showed similar biological activity in histamine release assays (n = 4).