CD8 T cell self-tolerance permits responsiveness but limits tissue damage.

Self-specific CD8T cells can escape clonal deletion, but the properties and capabilities of such cells in a physiological setting are unclear. We characterized polyclonal CD8 T cells specific for the melanocyte antigen tyrosinase-related protein 2 (Trp2) in mice expressing or lacking this enzyme (due to deficiency in , which encodes Trp2). Phenotypic and gene expression profiles of pre-immune Trp2/K-specific cells were similar; the size of this population was only slightly reduced in wild-type (WT) compared to -deficient () mice.