Full Breakdown
Cryo-Expansion Microscopy Reveals 3-D Architecture of Cytotoxic T Cells Within Human Tumors
5/9/2026, 6:25:02 AM
Breakthrough Imaging of Killer T Cells in Tumors
Researchers from the University of Geneva (UNIGE) and Lausanne University Hospital (CHUV) used cryo-expansion microscopy to capture images of cytotoxic T lymphocytes engaging cancer cells. The Cell Reports (1 April 2026) study revealed a dome-shaped membrane at the immune synapse and granules with single- or multi-core structures, features previously unresolved in intact cells.
Scientific Background and Lead Researchers
Cytotoxic T lymphocytes, the immune system’s “killer” cells, destroy infected or malignant cells by forming an immune synapse that directs toxic granules while sparing tissue. Imaging this interface is limited by preparation methods that can distort structures. The team—Florent Lemaître (UNIGE), Virginie Hamel (UNIGE) and Benita Wolf (CHUV)—was funded by the ISREC Foundation TANDEM program.
Methodology and Key Findings
The researchers used cryo-expansion microscopy, vitrifying cells to prevent ice crystals and embedding them in a hydrogel that expands isotropically. This maintains near-native architecture while enlarging features for imaging. Expanded samples revealed a dome-shaped membrane at the immune synapse and granules with single-core or multi-core internal structures.
Implications for Immuno-Oncology
The three-dimensional view of the immune synapse and granule architecture in tumor-infiltrating T cells offers a structural basis for understanding variable cytotoxic efficacy. The authors propose that these insights could inform therapies that boost T-cell engagement or granule delivery, potentially enhancing immuno-oncology outcomes.
Official Statements & Responses
Virginie Hamel noted that rapid vitrification and hydrogel expansion preserve cellular architecture, allowing detailed observation. Florent Lemaître emphasized the dome-shaped membrane at the contact site and its link to adhesion and organization. Benita Wolf highlighted that applying the method to human tumor samples enables nanometer-scale study of T-cell activity clinically, guiding therapeutic development.
Verbatim Quotes
> “This technique involves instantaneously freezing cells at very high speed, placing them in a so-called vitreous state, where water solidifies without forming crystals and thus faithfully preserves biological structures.” — Virginie Hamel, Senior Lecturer, UNIGE
> “The samples are then physically expanded using an absorbent hydrogel, making it possible to observe their internal organization with great precision while maintaining their near-native architecture,” explains Virginie Hamel, Senior Lecturer in the Department of Molecular and Cellular Biology at the Faculty of Science of UNIGE.” — Virginie Hamel, Senior Lecturer, UNIGE
> “Our work reveals that at the point of contact between the immune cell and its target, the membrane forms a kind of dome, whose structure appears to be linked to adhesion interactions and to the internal organization of the cell,” — Florent Lemaître, Postdoctoral Researcher, UNIGE
> “We extended this approach to human tumor tissues, making it possible to directly observe T lymphocytes infiltrating tumors and their cytotoxic machinery at the nanometer scale. This allows us to study immune responses directly in their clinical context and to better understand the mechanisms that determine their effectiveness,” — Benita Wolf, Chief Resident and Associate Researcher, CHUV
What’s Next
The researchers plan to apply cryo-expansion microscopy to additional tumor types and to correlate structural observations with functional assays, aiming to identify biomarkers that predict T-cell efficacy in patients.
