🧬 Scientists captured a first-of-its-kind 3D view of how killer T cells attack cancer

Cytotoxic T cells do not destroy cancer by simply flooding tissue with toxic molecules. They work with remarkable precision.

Their attack depends on a tiny contact zone called the immune synapse — a specialized interface where a killer T cell locks onto a target cell and delivers cytotoxic granules directly toward it.

Now researchers from the University of Geneva and CHUV/UNIL have visualized this machinery in 3D with nanometer-scale detail, using cryo-expansion microscopy. The technique rapidly freezes cells in a near-native state, then physically expands them in a hydrogel, making fine cellular architecture easier to resolve without destroying the tissue structure.

What they found:

🔹 the contact zone between the T cell and the cancer cell forms a complex dome-like membrane structure;
🔹 cytotoxic granules are not all the same — some contain a single active core, while others contain several;
🔹 the method was applied not only to isolated cells, but also to human tumor samples, allowing researchers to observe T cells and their killing machinery directly inside tissue;
🔹 this could help explain why immune attacks against tumors succeed in some cases and fail in others.

The real breakthrough is not just the image itself. It is the ability to study the architecture of immune killing in a more realistic biological context — a potentially powerful tool for improving cancer immunotherapy.

The study was published in Cell Reports in April 2026. Lead author: Florent Lemaître; co-supervisors: Virginie Hamel and Benita Wolf. https://www.sciencedaily.com/releases/2026/04/260429102021.htm