Fig. 2. The current landscape of known TCR–antigen pairs.
a, Number of T cell receptors (TCRs) containing α-chains, β-chains or paired chains, showing variation in numbers according to the data set (manually curated catalogue of pathology-associated TCR sequences (McPas-TCR), VDJ database (VDJdb), Immune Epitope Database (IEDB) and multiplex identification of TCR antigen specificity (MIRA)). b, Number of TCRs per antigen species of origin, showing that the majority of all antigens reported as binding a TCR are of viral origin. c, Cumulative frequency of antigens, showing that a group of 100 antigens makes up 70% of TCR–antigen pairs. d, Number of TCRs by HLA-A type, showing that known antigens are reported in complex with only a few common HLA alleles. e, Frequency histogram showing that most antigens have only one known cognate TCR in the combined data set5–8.