Single-cell TCR mapping reveals spatially coordinated T cell states in head and neck cancer.

Current spatial T cell receptor (TCR) profiling approaches lack the resolution needed to link clonal identity, transcriptional state, and spatial positioning of individual T cells in the tumor microenvironment. Here, we introduce a spatial TCR profiling strategy that resolves individual T cell clones together with their transcriptional states at single-cell resolution and applied the method to human head and neck squamous cell carcinoma. Presumed tumor-specific T cells were broadly dispersed throughout the tumor microenvironment, and cells of the same clone occupied distinct transcriptional states in different locations: Immune-rich regions contained more plastic or progenitor cells, whereas tumor-dense regions were enriched for exhausted states. Patients exhibited notably different spatial architectures of antitumor T cell responses, revealing variation that was not captured by high-resolution, spatially agnostic methods such as spectral flow cytometry and single-cell RNA sequencing. These results provide a blueprint for dissecting antigen-specific T cell states in human tumors and reveal how T cell states are spatially coordinated with local cues across the tumor microenvironment.