Picryl Chloride-Induced Contact Dermatitis in IQI/Jic Male Mice

Abstract

Ear skin responses to picryl chloride (PCL) were examined in IQI/Jic male mice. Following the sensitization with PCL to the shaved abdominal skin, the left ear was topically applied with PCL at 4, 11, 18 and 25 days later. The ear swelling responses tended to shift from delayed type to immediate one after the 4th application. The peak time of histopathological changes characterized by edema and inflammatory cell infiltration corresponded well with that of ear swelling responses, and marked elevation of total serum IgE levels and prominent increase in number of mast cells were observed after the 4th application. The numbers of CD4⁺ cells and Mac-1⁺ cells began to increase after the 1st application and much more increased after the 4th application while CD8⁺ cells increased after the 4th application. MHC class II⁺ cells increased mainly in the dermis after the 4th application, but CD19 ⁺ cells, i.e. B lymphocytes, were negligible throughout the experimental period. The present results suggest that not only CD4⁺ cells but also CD8⁺ cells may participate in the induction of PCL-induced contact dermatitis in IQI/Jic male mice and that the shift from Th1-dominant response to Th2-dominant one may occur following the repeated application.