Figure 5.

Long-term survivors have durable immune memory. A, Mice with no tumor by postimplantation day 100 were rechallenged with 2 × 10⁶ GL261-luc2 cells in the right flank and compared with 4 naïve control animals. Control mice developed flank tumors of 1,000 mm³ volume by postrechallenge week 7. None of the long-term survivors developed flank tumors by week 10. B, IVIS imaging on day 10 demonstrates strong bioluminescence in naïve controls, and no signal in the long-term survivors, with the exception of one mouse in the PD-1–treated group that showed weak signal. By day 14, the signal was no longer detectable in this animal (not shown). Rechallenge experiments were repeated in duplicate using all remaining survivors.