In genetically modified mice, researchers switched off a receptor after gamma-delta T cells had matured and settled in tissues. The cells stayed in place, but soon lost traits needed to monitor damage and respond quickly.
An international study published in Nature shows that the receptor does more than trigger development. Its signals must continue inside tissues to keep these immune cells alert and preserve their tissue-resident features, helping them react to abnormal cells.
The research was co-led by the Francis Crick Institute in England and the Universidad Complutense de Madrid, with help from the Centro de Biología Molecular Severo Ochoa, or CBM-CSIC-UAM. It examined a specialised lymphocyte found particularly often in the skin and intestine.
Gamma-delta T cells patrol tissues and can react fast when they encounter infected or abnormal cells, including damaged ones. Their surface receptor gathers information from the surrounding tissue. That signal helps the cells decide when to stay put and switch on, so they can defend the area.
This makes them a useful example of why the usual line between innate and adaptive immunity does not always hold. The cells respond quickly, like part of the innate immune system, but their readiness depends on continuing signals from an adaptive gamma-delta receptor.
The mouse experiment was designed to test mature cells, not just developing ones. Researchers used animals with an internal genetic switch that let them remove the receptor after the cells had fully developed and moved into tissues.
The effect was quick. The cells remained present, yet began to lose traits that helped them stay in tissue and track damage, making them less able to respond properly to injured cells. That setup separated the receptor's role in development from its role in maintaining an established immune function.
The receptor does more than guide gamma-delta T cells as they form. Its ongoing signals help keep mature cells ready to patrol.
Researchers then tested human gamma-delta T cells grown in the laboratory. Removing the receptor caused similar changes, especially in processes tied to immune defense and the cells' internal functions. Information from CSIC, the effect was not limited to one gamma-delta T-cell population or tissue.
The cancer tests gave the finding its clearest practical weight. In three mouse models of skin cancer and colon cancer, tumours appeared more often or grew larger when the cells lacked the receptor.
Human gamma-delta T cells without the receptor were also less able to slow melanoma and colorectal cancer cells in laboratory tests. The result points to lost function beyond changes in the cells' visible features.
Miguel Muñoz-Ruiz of the CBM-CSIC-UAM said the cells need continuing information from their surroundings to keep their defensive capacity. In this model, rapid immune action does not stay switched on by itself. It depends on an active link with the tissue.
That link helps explain how gamma-delta T cells can show traits tied to adaptive immunity and still respond with the speed usually associated with innate defenses. The receptor connects those two sides by helping mature cells maintain their readiness.
The result also raises a practical issue for cell-based immunotherapy. Transferring or expanding gamma-delta T cells may not be enough if the process strips away the receptor signals that support their work in tissue.
Cells could reach a tumour and remain detectable there, yet have less ability to sense damage or mount a fast response. Simply adding more cells may so fall short if their receptor function is not preserved.
The study is basic research, not a new cancer treatment. Its value lies in identifying a condition these immune cells need to keep monitoring tissue and hold back tumour growth.
The mouse experiments and laboratory tests with human cells support a mechanism and a therapeutic hypothesis. They do not show that the approach works in people.
Gamma-delta T cells remain a possible basis for cell therapy because they can directly damage tumour cells and respond quickly to changes around them. The 2026 review in Frontiers in Immunology lists four ways these cells can damage tumours: perforin and granzyme B, along with FasL and TRAIL. It also stresses that activity differs by cell subset and tumour microenvironment.
The receptor is so a possible target for future efforts to strengthen or control gamma-delta T-cell responses. The current evidence supports one firm finding: mature cells need continuing receptor signals to stay prepared.
