Psoriasis is an inflammatory disease with dynamic interactions between the immune system and the skin. The IL-23/Th17 axis plays an important role in the pathogenesis of
psoriasis, although the exact contributions of
IL-23 and
IL-17 in vivo remain unclear. K5.Stat3C transgenic mice constitutively express activated Stat3 within keratinocytes, and these animals develop skin lesions with histological and
cytokine profiles similar to those of human plaque
psoriasis. In this study, we characterized the effects of anti-mouse
IL-17A, anti-mouse
IL-12/23p40, and anti-mouse
IL-23p19 Abs on the development of
psoriasis-like lesions in K5.Stat3C transgenic mice. Treatment with anti-
IL-12/23p40 or anti-IL-23p19 Abs greatly inhibited 12-O-tetradecanoylphorbol-13-acetate-induced epidermal
hyperplasia in the ears of K5.Stat3C mice, whereas the inhibitory effect of an anti-IL-17A Ab was relatively less prominent. Treatment with anti-
IL-12/23p40 or anti-IL-23p19 Abs markedly lowered transcript levels of Th17
cytokines (e.g., IL-17 and IL-22), β-
defensins, and S100A family members in skin lesions. However, anti-IL-17A Ab treatment did not affect
mRNA levels of Th17
cytokines. Crossing IL-17A-deficient mice with K5.Stat3C mice resulted in partial attenuation of 12-O-tetradecanoylphorbol-13-acetate-induced lesions, which were further attenuated by anti-
IL-12/23p40 Ab treatment. FACS analysis of skin-draining lymph node cells from mice that were intradermally injected with
IL-23 revealed an increase in both IL-22-producing T cells and NK-22 cells. Taken together, this system provides a useful mouse model for
psoriasis and demonstrates distinct roles for
IL-23 and
IL-17.