Scientists decipher how T cells sense enemies—such as cancer—at point of contact - Medical Xpress

What the report says

Medical Xpress reported on July 27, 2026, that researchers led by the University of Oxford have identified nanoscale contact sites where T cells rapidly weigh activating and inhibitory signals when they encounter potential targets, including cancer cells. The work, carried out with collaborators in Austria and China and published in Science Immunology, focuses on the first moments of contact between immune cells and target cells.

According to the report, T cells use tiny finger-like structures called microvilli to probe other cells. The researchers examined how T cell receptors and the immune checkpoint protein PD-1 behave at these close-contact points. Using in vitro microscopy approaches and changes to receptor levels, binding properties, molecular dimensions and cell shape, the team found that PD-1 can be captured at microvillar contacts as they form. Once engaged, PD-1 limited T cell receptor signaling, recruited the signaling molecule SHP2 and reduced the T cell’s ability to spread against the target, a step linked to killing activity.

The findings matter because PD-1 is a central target of checkpoint blockade cancer immunotherapies, which aim to prevent tumors from suppressing immune attack. Medical Xpress noted an unexpected result involving nivolumab, sold as Opdivo: under certain experimental conditions, the antibody briefly encouraged the inhibitory signaling it is intended to block. The researchers also tested modified checkpoint-blocking antibodies that avoided trapping PD-1 at close contacts and produced stronger T cell activation in vitro.

The study does not by itself establish a new treatment, but it offers a more detailed view of where and how immune decisions are made at cell-to-cell interfaces. The authors and accompanying commentary suggest the work could inform future antibody design for cancer immunotherapy.