CELLULAR-INDUCTION MECHANISM OF CD8(-CELLS BY DMBA AND TPA - FORMATION OF CD4(+) SUPPRESSOR-INDUCER T-CELLS() SUPPRESSOR T)

We investigated the cellular induction mechanism of antigen-nonspecifi c CD8(+) T suppressor cells which suppressed delayed-type hypersensiti vity to sheep red blood cells, by treating BALB/c mice with 7,12-dimet hylbenz[a]anthracene (DMBA), a tumor initiator, and 12-O-tetradecanoyl phorbol 13-acetate (TPA), a tumor promoter. Macrophages were activated by painting with 400 nmol of DMBA on mice. And the macrophages plus T PA induced CD4(+) T suppressor inducer cells in the mice spleens. Thes e cells were efficient at inducing CD8(+) T suppressor-effector cells. When 8 nmol of TPA was painted daily on mice for 3 days following the treatment with 400 nmol of DMBA, or when spleen cells hom mice pretre ated with 400 nmol of DMBA were cultured in 32 nmol/5 mi of TPA for 3 days, inducer cells were formed in the spleen. Both T suppressor-induc er cells and macrophages from mice treated with DMBA were shown to act with the formation of soluble factors, which may be different from IL -10. (C) 1996 Academic Press, Inc.