Figure 6.

Fn14×CD3 BiTE mediates the distant migration of T cells, and IL-15 augments proliferation and persistence of Fn14 CAR-T/IL-15 cells in vivo. (A, D) Mouse tumors were subjected to MRI on day 28 (red circle), then specimens were harvested and stained for Fn14 and CD3 in order to evaluate the tumor-lytic activity and distant T cell infiltration. Scale bar, 20 μm. (B, C) Fn14 staining intensity and average percentage of CD3+ cells per field in different groups. (E-G) The peripheral blood of Fn14 CAR-T/IL-15-treated mice showed a higher percentage of CAR+ cells, fewer PD-1+ T cells, and higher level of IL-15 than Fn14 CAR-T cells on days 14 and 21. (H) Fn14 CAR-T/IL-15 cells secreted larger amounts of the inflammatory cytokines IFN-γ and TNF-α than Fn14 CAR-T cells did. **P < 0.01; ***P < 0.001