Figure 6.

In vivo suppression of allograft rejection by Ts1 cells re-cultured with PVG stimulators and rIL-12p70. Ts1 cells generated by culture of CD4⁺CD25⁺ T cells with PVG alloantigen and rIL-2 for 3 days were re-cultured with rIL-12p70 and PVG alloantigen for 4 days to produce Th1-like Treg (●). 5 × 10⁶ of the Th1-like Treg were given 3 days after grafting, as we expected by that time the rejection response producing IL-2, IL-12p70, and IFN-γ would be induced in the host, as described (32). These delayed PVG (top panel) but not third party Lewis (bottom panel) allograft rejection compared to normal rejection controls (○) (n = 5/group) (p < 0.01). In comparison, 5 × 10⁶ Ts1 cells that had been re-cultured with rIL-2 and PVG for 4 days (▴) did not delay rejection (n = 4), this demonstrated re-culture of Ts1 cells with rIL-12p70 was required to induce potent alloantigen-specific Treg that could suppress rejection.