The thymoproteasome in shaping the CD8 + T-cell repertoire.

The thymoproteasome is a type of proteasome expressed specifically in thymic cortical epithelial cells. Thymoproteasome affects antigen processing of major histocompatibility complex (MHC)-I-associated peptides and optimizes positive selection of CD8 T cells. However, it remains unanswered whether and how thymoproteasome-dependent MHC-I-associated self-peptides contribute to positive selection of cortical thymocytes. This short piece discusses the potential mechanisms of thymoproteasome contribution to positive selection of MHC-I-restricted CD8 T cells.