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. Author manuscript; available in PMC: 2016 May 4.
Published in final edited form as: Nat Rev Cancer. 2012 Mar 22;12(4):252–264. doi: 10.1038/nrc3239

Figure 5. Implications of the adaptive immune resistance mechanism for combinatorial immunotherapy of cancer.

Figure 5

The adaptive immune resistance mechanism implies that the blockade of an induced immune-checkpoint protein, such as programmed cell death protein 1 (PD1), as a single intervention will only induce tumour regressions when there is a pre-existing antitumour immune response to be ‘unleashed’ when the pathway is blocked. Multiple interventions, such as vaccines, that activate a de novo antitumour immune response may not induce tumour regressions because tumours respond by upregulating immune-checkpoint ligands. Therefore, combining the two approaches may induce tumour regressions in patients that would not have responded to either treatment alone. PDL1, PD1 ligand 1; TAM, tumour-associated macrophage.