Fig. 3: Notch/STAT3 co-stimulation enhances expression of several co-inhibitory receptors on human effector memory CD4⁺ T cells.

a FACS-purified human effector memory CD4⁺ T cells were cultivated in vitro w/ or w/o DLL4/Cyt (Cyt = IFN-α/IL-6/IL-21) co-stimulation. Representative flow cytometric profiles of CD49b vs. LAG-3 expression (left) and quantification of CD49b⁺LAG-3⁺ co-expressing cells (right) are shown. b Expression of PD-1, TIGIT and TIM3 by effector memory CD4⁺ T cells after cultivation and co-stimulaton w/ or w/o DLL4/Cyt (Cyt = IFN-α/IL-6/IL-21). Representative histograms (upper row). Quantification of PD-1 MFI, TIGIT⁺ and TIM3⁺ cells among effector memory CD4⁺ T cells (lower row) is shown. Each dot represents one healthy donor (n = 8–26). Two-tailed paired t test was performed (**P < 0.01; ***P < 0.001) to assess significance. Data are cumulative from up to seven experiments.