Eradication of spontaneous malignancy by local immunotherapy

Area of Science:

• Immunology
• Oncology
• Cancer Immunotherapy

Background:

• The immune system's potential to cure cancer is increasingly recognized.
• Current immunotherapies include custom-made antigen-targeted therapies and immune checkpoint inhibitors.
• Non-customized approaches like in situ vaccination offer alternative strategies.

Purpose of the Study:

• To evaluate a non-customized in situ vaccination strategy for cancer treatment.
• To identify effective immunoenhancing agents for triggering systemic anti-tumor immune responses.
• To assess the efficacy of combining Toll-like receptor 9 (TLR9) ligands with anti-OX40 antibody therapy.

Main Methods:

• Developed a screening assay using two implanted syngeneic tumors.
• Administered test agents to one tumor and monitored regression of the distant, untreated tumor.
• Investigated the combination of CpG (a TLR9 ligand) and anti-OX40 antibody.

Main Results:

• The combination of CpG and anti-OX40 antibody demonstrated significant anti-tumor efficacy.
• CpG induced OX40 expression on CD4+ T cells, enabling T cell activation by anti-OX40.
• This combination therapy led to the regression of distant tumors, indicating a systemic immune response.

Conclusions:

• In situ vaccination with CpG and anti-OX40 antibody is a potent, non-customized cancer immunotherapy.
• This approach can elicit a T cell immune response specific to tumor antigens.
• The combination therapy shows potential for curing multiple cancer types and preventing spontaneous cancers.