An unconventional integrin b3 and CD103 heterodimer improves the anti-tumor immunity of tissue-resident T cells

Current cancer immunotherapies promote recovery of CD103+ tissue-resident memory T cells (Trm) population of the tumor-infiltrating T lymphocytes (TILs). However, not all treated patients exhibit improved anti-tumor immunity and survival, likely due to the immunophenotypical diversity among the CD103+ Trm TILs. Utilising multifaceted proteomics approaches and patients’ clinical analyses, we discovered an unusual subset of CD8+ Trm TILs expressing non-canonical integrin β3 early during T cells activation. The integrin β3 surprisingly heterodimerises with CD103 on T cells, leading to unconventional granulysin-mediated cytotoxicity, elevated alternative bioenergy usage and efficient T cell migration, with minimal overall exhaustion. Importantly, early-stage non-small cell lung carcinoma (NSCLC) patients with enriched presence of integrin β3+CD103+ Trm TILs exhibited better clinical prognosis, with improved T cell immunophenotype, hence confirming the beneficial role of this unusual subset of Trm TILs. These unconventional anti-tumor T cell features provide new avenues and future opportunities for designing better translational immunotherapy strategies.