When naive T cells encounter antigen-presenting cells (APCs), membrane and cytoplasmic molecules rearrange at the T cell–APC contact area to form the immune synapse. Finetti et al. now reveal an ...

T cell activation requires a T cell receptor (TCR) to recognize its cognate peptide in the context of an MHC molecule. In addition, the association of CD3 with the TCR–peptide–MHC complex ...