*3.5. Sensitization and Challenge*

Two days before sensitization with PCl, cyclophosphamide was injected subcutaneously (150 mg/kg in distilled water) to remove proliferating immunosuppressive cells [15]. After removing coat hair, the mice were immunized by painting their abdominal skin with 0.05 mL of 7% PCl in ethanol:acetone (3:1). Two weeks after sensitization, 10 ΐg of peridinin, or fucoxanthin or hydrocortisone was painted onto the ears. 50 ΐg of peridinin or fucoxanthin was administered i.p. to these mice 3 h before the antigen challenge, and 0.02 mL of 1% PCl in acetone:olive oil (1:4) was painted on each ear lobe to challenge the mice. Ear thickness was measured with a dial thickness gauge (Peacock G-1M, Ozaki Mfg. Co. Ltd., Tokyo, Japan) before and after the challenge and was expressed as the mean thickness of each ear in micrometers. 
