DIFFERENTIAL MODULATION OF CONTACT HYPERSENSITIVITY AND DELAYED-HYPERSENSITIVITY REACTIONS BY TOPICAL APPLICATION OF 12-O-TETRADECANOYLPHORBOL-13-ACETATE

Ear/footpad swelling following sensitization and challenge with 2,4-di nitrofluorobenzene (DNFB)/allogenic splenocytes (AS) were used to moni tor the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on conta ct hypersensitivity (CHS) and delayed hypersensitivity (DHS) reactions , respectively. Topical treatment of dorsal or ventral SENCAR mouse sk in 4x with 2 mug of TPA prior to sensitization of dorsal skin with DNF B suppressed attempts to induce CHS by subsequent challenge with DNFB. The adoptive transfer of splenocytes isolated from mice pretreated on the dorsum with TPA prior to dorsal sensitization with DNFB inhibited the development of CHS to DNFB in recipient mice. Conversely, topical treatment with TPA prior to s.c. sensitization with AS neither suppre ssed subsequent attempts to induce DHS, nor resulted in the generation of a splenocyte population capable of suppressing DHS reactions in ad optive transfer studies. Thus, promoting doses of topically applied TP A has differential effects on CHS and DHS reactions.