Methods: Balb/c mice sensitized by intraperitoneal injections of anti-ovalbumin (OVA) IgE mAbs on days 0, 1, 2, 7, 8, and 9 were challenged with OVA by its application to the skin on days 1, 2, 3, 8, 9, and 10. Anti-OVA IgG1 mAb (O1-10) Fabs were applied to the skin 30 min before the fourth to sixth challenges followed by measurement of clinical symptoms including erythema/hemorrhage, edema, scarring/dryness, and excoriation/erosion of the skin. Histological changes in the skin were also investigated.
Results: Significantly increased clinical symptoms were observed during the third to sixth OVA challenges. The application of O1-10 Fabs to the skin resulted in marked suppression of all of the clinical symptoms. Intact O1-10 failed to affect the clinical symptoms. Histologically, epidermal thickness and neutrophil accumulation in the skin were decreased following the treatment with O1-10 Fabs. Furthermore, the suppression of the clinical symptoms by the O1-10 Fabs was associated with decreases in mast cells as well as IL-17A and IL-13 in the skin.
Conclusions: The present study demonstrates for the first time that the application of pathogenic allergen-specific IgG1 mAb Fabs to the skin appears to be effective in downregulating IgE-mediated atopic dermatitis-like skin inflammation.