Das G, Gould D S, Augustine M M, Fragoso G, Sciutto E, Stroynowski I, Van Kaer L, Schust D J, Ploegh H, Janeway C A
Section of Immunobiology, Yale University School of Medicine, and the Howard Hughes Medical Institute, New Haven, Connecticut 06520-8011, USA.
J Exp Med. 2000 Nov 20;192(10):1521-8. doi: 10.1084/jem.192.10.1521.
Murine intestinal intraepithelial lymphocytes (iIELs) are made up of a heterogeneous mix of T cells with unique phenotypes. Whereas CD8(+) T cells in peripheral lymphoid organs use CD8alpha/beta and are selected on MHC class Ia molecules, a majority of iIELs use CD8alpha/alpha. Here, we report that the presence of CD8alpha/alpha TCR-alpha/beta cells in iIELs is independent of classical MHC class I molecules K(b) and D(b), as illustrated by their presence in K(b)/D(b) double-knockout mice and in mice lacking a nonclassical MHC class I molecule, CD1d. Most strikingly, their presence is decreased by approximately 70% in mice lacking transporter associated with antigen processing (TAP). The TAP-dependent nonclassical MHC class I molecule Qa-2 is strongly implicated in the presence of these cells, as inferred from the low numbers of CD8alpha/alpha TCR-alpha/beta T cells in mice deficient in Qa-2 genes. Second, a Qa-2-transgenic mouse made in a Qa-2(-) strain showed an increase in the numbers of CD8alpha/alpha cells among its iIELs. Thus, the presence of CD8alpha/alpha TCR-alpha/beta cells in iIELs is mainly dependent on the nonclassical MHC class I molecule Qa-2.
小鼠肠道上皮内淋巴细胞（iIELs）由具有独特表型的T细胞异质性混合组成。在外周淋巴器官中，CD8(+) T细胞使用CD8α/β，并在MHC I类分子上进行选择，而大多数iIELs使用CD8α/α。在此，我们报告iIELs中CD8α/α TCR-α/β细胞的存在独立于经典MHC I类分子K(b)和D(b)，这在K(b)/D(b)双敲除小鼠以及缺乏非经典MHC I类分子CD1d的小鼠中得到了证明。最引人注目的是，在缺乏与抗原加工相关转运体（TAP）的小鼠中，它们的存在减少了约70%。从Qa-2基因缺陷小鼠中CD8α/α TCR-α/β T细胞数量较少可以推断，TAP依赖的非经典MHC I类分子Qa-2与这些细胞的存在密切相关。其次，在Qa-2(-)品系中构建的Qa-2转基因小鼠，其iIELs中CD8α/α细胞数量增加。因此，iIELs中CD8α/α TCR-α/β细胞的存在主要依赖于非经典MHC I类分子Qa-2。
