House dust mite major allergen Der f 1 enhances proinflammatory cytokine and chemokine gene expression in a cell line of canine epidermal keratinocytes

House dust mite (HDM) allergens are the most common allergens involved in the induction of IgE-mediated hypersensitivity. Recently, epicutaneous sensitization with HDM allergens has been emphasized in the development of atopic dermatitis (AD); however, direct stimulation of canine keratinocytes by mite allergens has not been well investigated. In the present study, we investigated the effects of Der f 1, a major allergen of Dermatophagoides farinae, on cytokine and chemokine gene expression in a canine keratinocyte cell line, CPEK. CPEK constitutively expressed mRNA for TNF-α, IL-12p35, IL-18, GM-CSF, TGF-β, IL-8/CXCL8, TARC/CCL17, CTACK/CCL27 and MEC/CCL28. Of all the cytokines and chemokines investigated in CPEK, transcription levels of GM-CSF, IL-8/CXCL8 and TNF-α mRNA were significantly enhanced by stimulation with Der f 1. The present results suggest that Der f 1 can directly augment inflammatory cytokine and chemokine production from keratinocytes, and may initiate allergic inflammation independently of Type-I hypersensitivity.