The cellular infiltrate of the contact sensitivity reaction to picryl chloride in the mouse.

Contact sensitivity to picryl chloride was studied in the mouse ear. The skin hypersensitivity, as a factor of ear swelling, and the intensity of the cellular infiltrate in the skin were evaluated together during the elicitation of the contact sensitivity reaction. It was found that the ear swelling is a mainly vascular reaction preceding the appearance of inflammatory cells. The infiltrating cells in this model of skin sensitivity were differentiated in Giemsa-stained plastic-embedded sections and recorded in a semi-quantitative way. When the cellular reaction was most intense at 48 and 72 hours after challenge, the most numerous inflammatory cells were lymphocytes and eosinophils.