Fig. 1.

Priming with lower-affinity peptide ligands leads to enhanced secondary responses but also increased sensitivity to TGFβ-mediated suppression. OT-I splenocytes were primed on peptide-loaded, irradiated EL4 cells for 5 days in vitro prior to restimulation with 100 ng/ml OVA₂₅₇ for all groups. Half of all samples were incubated in 20 ng/ml TGFβ starting at day 2 and during restimulation. Cells were analyzed by flow cytometry for polycytokine production in the CD3⁺CD8⁺CD44^hi antigen-experienced CD8⁺ T-cell gate. a Contour plots demonstrating differential cytokine output by cells primed with OVA₂₅₇ and the V4 APL in the presence and absence of TGFβ. Cytokine output for cells primed for 5 days with OVA257 but not restimulated is also shown. b Pie charts representing the proportion of effector CD8⁺ T cells producing all three cytokines (triple), a set of only two cytokines (double), only a single cytokine (single), or no cytokines (none), or the proportion of cells producing a precise combination of the three cytokines. Data shown are representative of at least three individual experiments with similar results