Chinese researchers have developed a pioneering partial treatment known as an “intra-tumour vaccine” that prevents cancer cells from suppressing immune functions while redirecting the body’s existing immune memory to attack tumours, offering a promising new approach to cancer treatment.
Although immune checkpoint blockade therapy has transformed cancer care by enhancing the immune system’s ability to target tumours, it remains ineffective for many patients. This limitation is largely due to the immune system’s inability to recognise malignant cells in cases where tumours carry a low mutation burden, resulting in a scarcity of new antigens that would normally trigger an immune response.
To overcome this challenge, the research team turned to a largely underused immune resource known as “bystander T cells”. These cells are generated in response to past infections, such as cytomegalovirus, and remain dormant while retaining immune memory in most adults.
The scientists proposed that if tumours could be made to display cytomegalovirus antigens, the body’s abundant reservoir of memory T cells could be mobilised to fight cancer. To achieve this, they designed a synthetic molecule called the “intra-tumour chimera vaccine”.
This dual-function molecule irreversibly degrades the PD-L1 protein in cancer cells, lifting a key brake on the immune system, while simultaneously delivering cytomegalovirus antigens. By marking tumours with this viral signature, the vaccine redirects virus-specific memory T cells to recognise and destroy cancer cells.
In both mouse models and tumour samples derived from patients, the intra-tumour chimera vaccine successfully activated T cells and demonstrated strong anti-tumour activity. The findings highlight the potential of harnessing immune memory against common viruses as a novel strategy in cancer therapy.
Chen Peng, a researcher at the Shenzhen Bay Laboratory, said the team is now developing translational molecules based on this mechanism and aims to advance the technology towards future clinical trials.
