Background: Indoor allergens derived from animals and mites often contribute to exacerbation of skin manifestations in atopic dermatitis (AD) patients.
Objective: To produce and characterize recombinant cat albumin, a cross-reactive animal allergen.
Methods: A complete cDNA coding for cat albumin was obtained by RT-PCR amplification from cat liver RNA. Recombinant cat albumin was expressed in Escherichia coli as hexahistidine-tagged protein, purified by nickel affinity chromatography and studied for IgE reactivity with sera from cat-allergic patients by ELISA and immunoblotting. Furthermore, CD203c expression of basophils from cat-allergic patients upon exposure to recombinant cat albumin was analysed.
Results: Recombinant cat albumin, a cross-reactive animal allergen sharing most IgE epitopes with its natural counterpart, was produced in E. coli. It was recognized preferentially by IgE from AD patients and elicited IgE-dependent basophil activation in sensitized patients.
Conclusions: Recombinant cat albumin may be used as a paradigmatic tool to analyse mechanisms of allergen-triggered exacerbation of AD, for diagnostic and, perhaps for therapeutic purposes.