Fig. 1

Galunisertib blocks TGFβ1 mediated suppression of naïve T cell proliferation and blocks Treg mediated suppression of naïve T cells. a Human CD8⁺ cells purified from healthy donor whole blood where labeled with CFSE and stimulated with anti-CD3/CD28 beads in the presence of TGFβ1 and galunisertib. CD8⁺ T cell proliferation was measured by assessing CFSE dilation by flow cytometry after 5 days of culture. Percent recovery of CD8⁺ T cell proliferation at different concentrations of galunisertib (0-10 μM) as indicated and representative histograms are shown. DMSO was used as vehicle control. Data shown are combined data of 4 healthy donors. b Human CD4⁺CD25⁺ cells purified from healthy donor whole blood where labeled with CFSE and stimulated with anti-CD3/CD28 beads in the presence of galunisertib. Autologous CD4⁺CD25⁻ Treg were added at a 1:1 ratio of Treg cells to naïve T cells. Naïve CD4⁺CD25⁻ T cell proliferation was measured by assessing CFSE dilation by flow cytometry after 5–7 days of culture. Percent recovery of CD4⁺CD25⁻ T cell proliferation at different concentrations of galunisertib (0-10 μM) as indicated and representative histograms are shown. Data shown are combined data of 4 healthy donors; representative of 3 independent experiments. One-way ANOVA with Dunnett’s test was used to compare the galunisertib treatments to the DMSO treatment. ****: p ≤ 0.0001; ***: p ≤ 0.001; **: p ≤ 0.01; *: p ≤ 0.05; ns: p ≥ 0.05