Defining Functional T Cell Receptor Repertoires With Nanovial-Based Screening.

T-cell receptor repertoires are commonly characterized through sequence diversity and antigen binding, while the cellular functions associated with individual receptors are often measured separately. In this review, I consider how functional information can be incorporated more directly into repertoire analysis by linking receptor identity with measurable effector outputs at single-cell resolution. I focus on Nanovial-based technologies that combine antigen-specific capture, stimulation, secretion measurement, viable-cell recovery, and downstream sequencing in workflows compatible with flow cytometry and single-cell sequencing platforms. Studies using conventional peptide-major histocompatibility complex ligands, the non-classical antigen-presenting molecules MR1 and CD1d, and secretion-encoded single-cell sequencing illustrate how these approaches can complement binding-based enrichment by adding information about secretory effector responses. I also discuss the extension of this framework from ligand-defined screening to dyad-resolved assays involving target cells, which can reveal how receptor identity relates to transcriptional and functional programs arising during direct cell-cell interactions. Together, these developments provide tools for studying relationships among TCR sequence, antigen recognition, and cellular response, with potential applications in therapeutic receptor discovery and in generating datasets for predictive models of T-cell function.