Fig. 1.

TGF-β preferentially inhibits cytotoxicity of memory CD8+ T cells in a dose-dependent manner. (A) Schematic of naive OT-I CD8+ T cell adoptive transfer, memory OT-I T cell generation with VSV-OVA, T cell isolation with magnet-activated cell sorting (MACS) from Ag-experienced OT-I memory mice, and subsequent ex vivo stimulation and analysis. Stimulation was 24 h with plate-bound anti-CD3 and anti-CD28 (CD3/28) in the presence or absence of TGF-β at 100 ng/mL. (B) Representative expression and gating of IFN-γ and GzmB in OT-I T_mem after stimulation. (C) IFN-γ and GzmB frequencies. Each point represents an individual animal, with connecting lines across points from the same animal (n = 14 animals). Statistical significances were calculated using paired t tests. (D) Frequencies of IFN-γ and GzmB in OT-I T_mem post 24 h stimulation with CD3/28 in the presence of titrated TGF-β (n = 7). TGF-β was titrated in twofold dilutions starting with 20 ng/mL and ending with 0.04 ng/mL, in fivefold dilutions starting with 20 ng/mL and ending at 0.032 ng/mL, and in fivefold dilutions starting with 1 ng/mL and ending at 0.0016 ng/mL. Each point represents an individual animal with connecting lines across points from the same animal. Data shown are from 6 to 14 independent experiments.