Figure 3.

Antigen specificity of unresponsiveness to DNFB – single challenge experiments. Positive controls for CH to DNFB (Group A) or oxazolone (Group C) were sensitized epicutaneously with the appropriate hapten and challenged with the same hapten 12 days later. Negative controls for CH to DNFB (Group B) or oxazolone (Group D) encountered hapten for the first time during ear challenge. Animals in Group E were sensitized epicutaneously with 185 mg DNFB followed 7 days later by s.c. injection of 5000 DNP-Mφ#59 treated with TGF-β₂. Animals in Group E were ear challenged with DNFB 12 days after sensitization. Group F mice were sensitized epicutaneously with oxazolone (500 mg), followed 7 days later by injection of 5000 DNP-Mφ#59 treated with TGF-β₂, and challenged with oxazolone 12 days after sensitization. Ear swelling was measured 24 and 48 hr after challenge, 24-hr ear swelling measurements are shown. Mean values significantly less than the positive control (P < 0·005) are marked by *.