Fig. 4

Disruption of activin-A signaling in CD4⁺ T cells accelerates lung tumor progression and alters the profile of tumor-infiltrating CD4⁺ T cells. A Survival plot of CD4/ALK4-KO or WT LLC-OVA-tumor bearing mice (n = 12). B Representative macroscopic images of lung lobes. C Representative photomicrographs of H&E-stained lung sections (scale bars: 100 μm). D Representative flow cytometry plots (left) and percentages of CD3⁺CD4⁺ T cells among CD45⁺ lung tumor-infiltrating cells (right). E Cytokine levels in supernatants of lung tumor-infiltrating CD4⁺ T cells. Data are mean ± SEM of triplicate wells. F Representative flow cytometry plots (left) and cumulative MFI values of PD-1, CTLA-4 or LAG-3 expression by CD3⁺CD4⁺ T cells infiltrating lung tumors (right). G Representative flow cytometry plots (left) and cumulative percentages of Foxp3-expressing cells among CD3⁺CD4⁺ T cells infiltrating lung tumors (right). H Representative flow cytometry plots (left) and cumulative percentages of IFN-γ-expressing cells among CD3⁺CD4⁺ T cells infiltrating lung tumors (right). I Representative flow cytometry plot (left) and cumulative percentages of CD3⁺CD4⁺CFSE^low T cells isolated from lung tumors (right). Data are mean ± SEM and are representative of 7 (D-H) and 4 (I) independent experiments. Statistical significance was obtained by Log-rank (Mantel-Cox) test and unpaired Student’s t-test; *P < 0.05, **P < 0.01 and ***P < 0.001