Activated integrins identify functional antigen-specific CD8 ⁺ T cells within minutes after antigen stimulation

Abstract

Significance Assessing antigen-specific T cells is crucial for our understanding of immune reactions against pathogens and tumors, and for evaluating immunotherapies in patients. Existing techniques to evaluate the functionality of T lymphocytes all rely on de novo expression of proteins, typically intracellular cytokines, and therefore require elaborated protocols and reagents. We have established a simple flow cytometry-based method to assess the functionality of CD8 + T cells by identifying immediate changes in the conformation and valency of cell surface integrins that occur within minutes following antigenic stimulation. Because of its robustness, sensitivity, and broad applicability, the assay can be rapidly implemented for the measurement and isolation of functional T cells for basic research and in the clinical setting.