Cao et al. developed StriMap – a prediction framework for modeling peptide–HLA presentation and TCR recognition as a coupled process based on physicochemical, sequence-context, and structure-informed representations that capture relevant constraints. StriMap was successfully used to screen bacterial peptides and identity candidates to activate TCRs associated with ankylosing spondylitis (AS), and a top candidate in AS was also confirmed in IBD, linking the two autoimmune diseases. In cancer, StriMap demonstrated efficacy for both TCR selection in adoptive cell therapy, and prioritizing potential neoepitopes for personalized cancer vaccines.

Contributed by Lauren Hitchings

ABSTRACT: The interaction between T cell receptors (TCRs), peptides, and human leukocyte antigens (HLAs) underlies antigen-specific T cell immunity. Despite substantial advances in peptide-HLA presentation prediction, accurate modeling of coupled TCR-peptide-HLA recognition remains underdeveloped, limiting applications such as TCR and neoepitope prioritization in cancer and antigen identification in autoimmunity. Here we present StriMap, a unified framework for predicting TCR-peptide-HLA interactions by integrating physicochemical, sequence-context, and structural features at recognition interfaces. StriMap achieves state-of-the-art performance with improved generalizability and enables applications in both cancer and autoimmunity. As a case study in ankylosing spondylitis (AS), we screened 13 million peptides derived from 43,241 bacterial proteins and identified candidate molecular mimics that were experimentally validated to activate T cells expressing an AS-associated TCR. Notably, a top validated peptide was enriched in patients with inflammatory bowel disease (IBD), suggesting potential shared microbial triggers between AS and IBD. Overall, StriMap provides a generalizable framework for rational immunotherapy design and for dissecting antigenic drivers of autoimmunity.

Author Info: (1) Broad Institute of MIT and Harvard, Cambridge, MA, United States. (2) Broad Institute of MIT and Harvard, Cambridge, MA, United States. Department of Molecular Biology, Massach usetts General Hospital and Harvard Medical School, Boston, MA, United States. (3) Broad Institute of MIT and Harvard, Cambridge, MA, United States. (4) Broad Institute of MIT and Harvard, Cambridge, MA, United States. (5) Broad Institute of MIT and Harvard, Cambridge, MA, United States. (6) Broad Institute of MIT and Harvard, Cambridge, MA, United States. Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States. (7) Broad Institute of MIT and Harvard, Cambridge, MA, United States. (8) Broad Institute of MIT and Harvard, Cambridge, MA, United States. Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States. (9) Broad Institute of MIT and Harvard, Cambridge, MA, United States. Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, United States. (10) Broad Institute of MIT and Harvard, Cambridge, MA, United States. Massachusetts Institute of Technology, Cambridge, MA, United States. (11) Broad Institute of MIT and Harvard, Cambridge, MA, United States. Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States. Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, United States. Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Boston, MA, United States.