Single-nucleus multimodal spatial transcriptomics reveals spatial colocalization of neoantigen-expressing tumor cells and cognate T cells.

Improved methods to identify therapeutically relevant tumor neoantigens and their cognate T cells would aid the development of precision medicines for cancer. Here, we developed Slide-GoTags, a droplet-based single-nucleus spatial transcriptomics approach that characterizes neoantigen-specific immunity by integrating targeted transcript genotyping and T cell receptor (TCR) sequencing with single-nucleus RNA sequencing from the same slice of frozen tissue. Application of Slide-GoTags to mouse and human tumors revealed colocalization of clonally expanded, neoantigen-specific T cells with tumor cells expressing their cognate neoantigen. We also identified distinct spatial immune landscapes shaped by anti-PD1 or anti-CTLA4 blockade in mouse colorectal tumors. Across human tumor types, Slide-GoTags detected TCR-neoantigen interactions through spatial proximity and identified an enrichment of interferon-driven immunogenicity niches in immunologically 'hot' tumors compared to 'cold' tumors. These niches harbored three T cell clonotypes that colocalized with genotyped neoantigens, highlighting a spatially organized antitumor immune response. Collectively, Slide-GoTags establishes a framework for in situ mapping of T cell-tumor interactions directly from individual tissue.