Enhanced tumor eradication by combining CTLA-4 or PD-1 blockade with CpG therapy. J Immunother. 2010;33:225-235. [PMID: 20445343 DOI: 10.1097/CJI.0b013e3181c01fcb]

Tumor vaccines and beyond

For the last two decades the immunotherapy of patients with solid and hematopoietic tumors has met with variable success. We have reviewed the field of tumor vaccines to examine what has worked and what has not, why this has been the case, how the anti-tumor responses were examined, and how we can make tumor immunity successful for the majority of individuals rather than for the exceptional patients who currently show successful immune responses against their tumors.

Clinical experiences with anti-CD137 and anti-PD1 therapeutic antibodies

Monoclonal antibodies (mAbs) provide a pharmacological platform to block or activate the function of surface receptors. The immune system has evolved receptor-ligand pairs that repress or empower the cellular immune response, which, if tampered with, unleash more potent cellular immunity against tumor antigens. Agonist antibodies directed against CD137 (4-1BB) on the surface of antigen-primed T lymphocytes increase tumor immunity that is curative against some transplantable murine tumors. A fully human IgG4 anti-CD137 antibody is under development with signs of clinical activity and cases of severe liver toxicity that seem to be on-target and dose-dependent effects. Programmed death-1 (PD1) is a surface molecule delivering inhibitory signals important to maintain T-cell functional silence against their cognate antigens. Interference with PD1 or its ligand PD-L1 (B7-H1) increases antitumor immunity. As a result anti-PD1 and anti-PD-L1 human mAbs are under clinical development. Phase I trials with anti-PD1 mAb have yielded encouraging results with durable objective responses and a reasonable safety profile. As new class of drugs in cancer therapy, immunostimulatory mAbs have resulted in redefinition of tumor response criteria and rethinking of the rationale for combining these among each other and with other strategies.

CpG oligodeoxynucleotides enhance the efficacy of adoptive cell transfer using tumor infiltrating lymphocytes by modifying the Th1 polarization and local infiltration of Th17 cells

Adoptive cell transfer immunotherapy using tumor infiltrating lymphocytes (TILs) was an important therapeutic strategy against tumors. But the efficacy remains limited and development of new strategies is urgent. Recent evidence suggested that CpG-ODNs might be a potent candidate for tumor immunotherapy. Here we firstly reported that CpG-ODNs could significantly enhance the antitumor efficacy of adoptively transferred TILs in vivo accompanied by enhanced activity capacity and proliferation of CD8⁺ T cells and CD8⁺ T cells, as well as a Th1 polarization immune response. Most importantly, we found that CpG-ODNs could significantly elevate the infiltration of Th17 cells in tumor mass, which contributed to anti-tumor efficacy of TILs in vivo. Our findings suggested that CpG ODNs could enhance the anti-tumor efficacy of adoptively transferred TILs through modifying Th1 polarization and local infiltration of Th17 cells, which might provide a clue for developing a new strategy for ACT based on TILs.