Development of Cd8α/α and Cd8α/β T Cells in Major Histocompatibility Complex Class I–Deficient Mice

Peripheral CD8(+) T cells mainly use CD8α/β, and their development is mainly dependent on the major histocompatibility complex (MHC) class I proteins K(b) and D(b) in H-2(b) mice. In this report, we have shown that the development of CD8α/β TCR-α/β cells in lymphoid organs as well as in intestinal intraepithelial lymphocytes (iIELs) is dependent on the MHC class I K(b) and D(b) proteins. In contrast, TCR-α/β CD8α/α cells are found mainly in iIELs, and their numbers are unaffected in K(b)D(b) double knockout mice. Most of the TCR-γ/δ cells in the iIELs also bear CD8α/α, and they are also unaffected in K(b)D(b) −/− mice. In β2-microglobulin (β2m)-deficient mice, all of the TCR-α/β CD8α/α and CD8α/β T cells disappear, but TCR-γ/δ cells are unaffected by the absence of β2m.