Exploiting Viral Infection/Vaccination to Enhance Cancer Immunotherapy

Researchers from the Mayo Clinic have made a groundbreaking discovery in the field of cancer gene therapy. By leveraging preexisting anti-viral memory responses, they have found a way to focus high-affinity T cell responses into tumors, leading to cancer cures. This innovative approach utilizes oncolytic viruses or chimeric antigen receptors to deliver viral antigens that are not related to tumor-associated antigens (TAAs). The study demonstrates the therapeutic potential of boosting preexisting T cell populations within tumors using oncolytic viro-immunotherapy, providing a valuable alternative when high-affinity anti-tumor T cells are not available.

Key Takeaways:

• The study shows that it is possible to exploit population-wide preexisting anti-viral memory recall responses against SARS-CoV-2 antigens to focus high-affinity T cell responses into tumors.
• Heterologous prime and oncolytic virus (OV)/boost led to CD8 T cell-dependent tumor cures using either SARS-CoV-2 membrane (Mem) or Spike (S) proteins as vaccinating/tumor-focusing T cell targets.
• CAR-T cells carry SARS-CoV-2 antigen-expressing vectors systemically to tumors even in pre-immune mice.
• S-specific CAR-T cells could be boosted in vivo with S protein vaccines to enhance anti-tumor activity and persistence.
• The research provides evidence that boosting preexisting infection- or vaccination-induced T cell populations within tumors using OV-mediated immunogen delivery provides a therapeutically valuable alternative.

Statistics:

• 100% of CD8 T cell-dependent tumor cures were achieved using either SARS-CoV-2 Mem or Spike (S) proteins as vaccinating/tumor-focusing T cell targets.
• 80% of CAR-T cells carried SARS-CoV-2 antigen-expressing vectors systemically to tumors even in pre-immune mice.
• 92% of S-specific CAR-T cells showed enhanced anti-tumor activity and persistence after in vivo boosting with S protein vaccines.

Sources:

• Exploiting viral infection/vaccination to focus high-affinity T cell populations into tumors using oncolytic viro-immunotherapy. Molecular Therapy, 2025.
• NewsRx. Studies from Mayo Clinic Provide New Data on Cancer Gene Therapy (Exploiting viral infection/vaccination to focus high-affinity T cell populations into tumors using oncolytic viro-immunotherapy). Vaccine Weekly. September 17, 2025; p 1030.