The neoantigen quality model: Is closer to self more non-self?

T cells recognize antigens from pathogens and transformed cells. Yet what antigen is "ideal"? We propose a theoretical framework in which recognition is governed by T cell selection maximized near, not far from, self. Genomic errors generate antigens closer to self that paradoxically overlap with pathogen antigens and are immunogenic and non-self. We formalize this concept as the Neoantigen Quality Model, recasting antigen recognition as an adaptation to surveil the self and non-self living worlds.