Antigen discrimination by T cells relies on size-constrained microvillar contact

T cells can use TCR on microvilli to interact with peptide-MHC (pMHC) complexes on antigen presenting cells. Here the authors characterise how T cells use microvilli to interrogate reconstituted membranes for pMHC complexes and how this is regulated by a balance between glycoproteins/glycocalyces that reduce detection, and the small adhesion protein CD2, which enhances detection.