The effects of blocking endogenous activin-A with follistatin on influenza matrix specific CD8⁺ T-cell expansion. Immature MoDCs were pulsed with inactivated influenza particles together with ISCOMATRIX adjuvant for 6 hours before washing and coculture with purified autologous CD8⁺ T cells with or without addition of 400 ng/mL follistatin. After 9 days, cultures were counted and restimulated with influenza matrix peptide pulsed T2 cells together with anti-CD107a antibody in the presence of brefeldin-A. (A-C) Typical analysis. (D) Percentage of IFN-γ⁺ CD8⁺ T cells. (E) Total IFN-γ⁺ CD107a⁺ CD8⁺ T cells, calculated from 4 individual donors. *P ≤ .02, **P ≤ .05 versus no follistatin.