Lin T, Matsuzaki G, Yoshida H, Kenai H, Omoto K, Umesue M, Singaram C, Nomoto K
Section of Gastroentrology, University of Wisconsin Hospitals, Middleton 53792, USA.
Cell Immunol. 1996 Jul 10;171(1):132-9. doi: 10.1006/cimm.1996.0183.
Murine T cell receptor (TCR) alpha beta intestinal intraepithelial lymphocytes (IEL), which express the CD8 molecule as a homodimer (CD8 alpha alpha), can be divided into two subsets: those which are CD4+ (CD4+CD8+alpha alpha) and those which are CD4- (CD4-CD8+alpha alpha). Here, we demonstrate that most TCR alpha beta CD4+CD8+alpha alpha IEL and TCR alpha beta CD4-CD8+alpha alpha IEL subsets appear to be of thymus origin, as neonatal thymectomy of BALB/c mice on Day 3 nearly eliminated both subsets. To further support this hypothesis, we demonstrate by grafting the thymus of CBF1 (BALB/c x C57BL/6) mice into nude mice that the thymus is capable of generating both TCR alpha beta CD4-CD8+alpha alpha IEL and TCR alpha beta CD4+CD8+alpha alpha IEL. However, which of the two TCR alpha beta IEL subsets is generated depends largely on the age of the thymus. The thymus from fetal up to 2 weeks of age generates predominantly TCR alpha beta CD4-CD8+alpha alpha IEL, but very scant amounts CD4+CD8+alpha alpha IEL. In contrast, the thymus after 2 weeks of age generates very little TCR alpha beta CD4-CD8+alpha alpha IEL, but generates an abundant amount of TCR alpha beta CD4+CD8+alpha alpha IEL. These results are consistent with the observation in euthymic mice that TCR alpha beta CD4-CD8+alpha alpha IEL precede the appearance of TCR alpha beta CD4+CD8+alpha alpha IEL by several weeks, thus further suggesting that the thymus is the major source of both TCR alpha beta IEL subsets.
表达同型二聚体CD8分子（CD8αα）的小鼠T细胞受体（TCR）αβ肠上皮内淋巴细胞（IEL）可分为两个亚群：CD4 +（CD4 + CD8 +αα）亚群和CD4 -（CD4 - CD8 +αα）亚群。在此，我们证明大多数TCRαβCD4 + CD8 +αα IEL和TCRαβCD4 - CD8 +αα IEL亚群似乎起源于胸腺，因为在第3天对BALB / c小鼠进行新生期胸腺切除几乎消除了这两个亚群。为了进一步支持这一假设，我们通过将CBF1（BALB / c×C57BL / 6）小鼠的胸腺移植到裸鼠中证明，胸腺能够产生TCRαβCD4 - CD8 +αα IEL和TCRαβCD4 + CD8 +αα IEL。然而，产生的两个TCRαβ IEL亚群中的哪一个很大程度上取决于胸腺的年龄。从胎儿期到2周龄的胸腺主要产生TCRαβCD4 - CD8 +αα IEL，但产生的CD4 + CD8 +αα IEL数量很少。相反，2周龄后的胸腺产生的TCRαβCD4 - CD8 +αα IEL很少，但产生大量的TCRαβCD4 + CD8 +αα IEL。这些结果与正常胸腺小鼠中TCRαβCD4 - CD8 +αα IEL比TCRαβCD4 + CD8 +αα IEL提前数周出现的观察结果一致，从而进一步表明胸腺是两个TCRαβ IEL亚群的主要来源。
