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-dinitrofluorobenzene (DNFB)/allogenic splenocytes (AS) were used to monitor the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on contact hypersensitivity (CHS) and delayed hypersensitivity (DHS) reactions, respectively. Topical treatment of dorsal or ventral SENCAR mouse skin 4x with 2 micrograms of TPA prior to sensitization of dorsal skin with DNFB 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 suppressed subsequent attempts to induce DHS, nor resulted in the generation of a splenocyte population capable of suppressing DHS reactions in adoptive transfer studies. Thus, promoting doses of topically applied TPA has differential effects on CHS and DHS reactions.