Intraperitoneal administration of CC10 during sensitization decreases OPN expression in sinonasal mucosa and spleens. (A) Decreased numbers of total inflammatory cells, eosinophils, and lymphocytes in NLF and reduced mRNA relative expression levels of IL-4, IL-5, and IL-13 in the nasal mucosa in CC10-knockout AR mice with CC10 treatment compared with those with PBS treatment. Solid columns = control mice sensitized with PBS; gray columns = AR mice. n = 4 to 5 mice per group. (B) Representative photomicrographs of OPN immunohistochemical staining of nasal tissue sections from a) CC10-knockout control mice without AR, b) CC10-knockout AR mice with PBS treatment, and c) CC10-knockout AR mice with CC10 treatment during sensitization. Scale bar, 50 μm. (C) Down-regulated protein and mRNA expression of OPN in nasal mucosal in CC10-knockout AR mice with CC10 treatment compared with those with PBS treatment. Solid columns = control mice; gray columns = AR mice. n = 4 to 5 mice per group. (D) a) Reduced mRNA relative expression levels of OPN in the spleen in CC10-knockout AR mice with CC10 treatment compared with those with PBS treatment. Solid columns = control mice; gray columns = AR mice. n = 4 to 5 mice for each group; b) CC10 suppresses OVA-induced OPN expression by spleen mononuclear cells derived from OVA sensitized wild-type mice in vitro. n = 3. * P < 0.05 and ** P < 0.01.