Intratumoral Vaccine Chimera Enables Immune Memory To Target Cancer

Chinese scientists report a new approach to cancer treatment that uses an intratumoral vaccine molecule to reshape immune responses. The molecule blocks tumour immune suppression and pulls on existing immune memory, helping the body recognise and attack cancer cells more effectively.

The work by researchers from Shenzhen Bay Laboratory and Peking University appears in the journal Nature. It addresses patients who do not respond to immune checkpoint blockade therapy, which, despite wide use in cancer treatment, still fails to benefit many individuals.

The team focused on tumours with a low mutational burden and few neoantigens. Such cancers often escape detection because immune cells struggle to distinguish malignant tissue from normal tissue. This situation reduces the impact of existing immunotherapy methods for many patients.

Researchers instead looked at bystander T cells, an immune resource present in most adults. These T cells form after earlier infections, including cytomegalovirus, and then stay in the body as memory cells. They usually remain inactive but can react quickly if they recognise their target.

The scientists suggested that tumours could be forced to display cytomegalovirus antigens on their surface. In that case, the many memory T cells specific to cytomegalovirus might be redirected to recognise tumour tissue, turning a viral defence mechanism into a potential cancer treatment tool.

To test this idea, the group created a synthetic construct called an intratumoral vaccination chimera. This dual-action molecule is designed to bind to tumour cells, remove the PD-L1 protein that suppresses immunity, and at the same time deliver a defined cytomegalovirus antigen epitope.

Laboratory results on the intratumoral vaccine and immune memory in cancer treatment intratumoral vaccine immune memory

Once tumours carry this viral marker, the body’s pool of anti-cytomegalovirus T cells can more easily detect them. The redirected T cells are then able to attack cancer cells that previously avoided immune surveillance, strengthening the overall anti-tumour response.

Evidence came from both animal studies and human samples. In mouse models and patient-derived tumour clusters, the intratumoral vaccination chimera activated T cells and showed strong anti-tumour effects. The findings suggest immune memory to common viruses could support broader cancer therapy strategies.

Researchers at Shenzhen Bay Laboratory are now working on translational molecules based on this mechanism. The group, led by senior investigator Chen Peng, aims to refine the intratumoral vaccine approach and move the technology towards clinical testing in future cancer treatment studies.

With inputs from WAM