Characterization of arginine kinase, anovel allergen of dermatophagoides farinae (Der f 20)

Objective: To characterize a novel allergen, the Dermatophagoides farinae-derived arginine kinase (Der f 20). Methods: The protein of Der f 20 was synthesized by genetic engineering approaches. The allergenicity of Der f 20 was tested by enzyme-linked immunosorbent assay and an airway allergy mouse model. Results: The Der f 20 gene was cloned andpresented in the Gene Bank with an accession number of AAP57094. The Der f 20 is an arginine kinase (AK), whichshowed a close relationship with D. pteronyssinus AK and Aleuroglyphusovatus AK. Western-blot and ELISA studies showed the IgE binding capacity of Der f 20 was 66.7% in the sera from 6 dust mite allergic patients. Immune inhibition assayresults showed the IgE cross-reactivity between Der f 20 and DME (Dust mite extract). Positive responses to Der f 20 were 41.2% as shown by skin prick tests in 17 DME-allergic patients. In vitro experimental results showed that Der f 20 induced Th2 cell differentiation and the expression of T cell Ig mucin domain molecule-4 (TIM4) in DCs. Conclusions; The Der f 20 protein is a novel subtype of thedust mite allergen.