CD8 T cells originate from hematopoietic stem cells in the bone marrow but mature in the thymus. During thymic maturation, precursor T cells undergo positive and negative selection processes to ensure that they can recognize MHC class I molecules and are not autoreactive. Successful maturation results in the release of naïve CD8 T cells into the peripheral bloodstream, where they circulate until they encounter their specific antigen presented by an MHC class I molecule.
