André Sébastien, Kerfourn Fabienne, Affaticati Pierre, Guerci Aline, Ravassard Philippe, Fellah Julien S
UMR 7622, National Centre for Scientific Research, and Hôpital Pitié Salpêtrière, Pierre and Marie Curie University, Paris, France.
Eur J Immunol. 2007 Jun;37(6):1621-33. doi: 10.1002/eji.200636375.
Gammadelta T cells localize at mammalian epithelial surfaces to exert both protective and regulatory roles in response to infections. We have previously characterized the Mexican axolotl (Ambystoma mexicanum) T cell receptor delta (TRD) chain. In this study, TRD repertoires in spleen, liver, intestine and skin from larvae, pre-adult and adult axolotls were examined and compared to the thymic TRD repertoire. A TRDV transcript without N/D diversity, TRDV1S1-TRDJ1, dominates the TRD repertoires until sexual maturation. In adult tissues, this canonical transcript is replaced by another dominant TRDV1S1-TRDJ1 transcript. In the thymus, these two transcripts are detected early in development. Our results suggest that gammadelta T cells that express the canonical TRDV1S1-TRDJ1 transcript emerge from the thymus and colonize the peripheral tissues, where they are selectively expanded by recurrent ligands. This particular situation is probably related to the neotenic state and the slow development of the axolotl. In thymectomized axolotls, TRD repertoires appear different from those of normal axolotls, suggesting that extrathymic gammadelta T cell differentiation could occur. Gene expression analysis showed the importance of the gut in T cell development.
γδ T细胞定位于哺乳动物上皮表面，在应对感染时发挥保护和调节作用。我们之前已对墨西哥钝口螈（Ambystoma mexicanum）的T细胞受体δ（TRD）链进行了表征。在本研究中，我们检测了幼体、亚成体和成体钝口螈脾脏、肝脏、肠道和皮肤中的TRD谱系，并与胸腺TRD谱系进行了比较。一种没有N/D多样性的TRDV转录本TRDV1S1-TRDJ1在性成熟前主导着TRD谱系。在成体组织中，这种典型转录本被另一种占主导地位的TRDV1S1-TRDJ1转录本所取代。在胸腺中，这两种转录本在发育早期即可检测到。我们的结果表明，表达典型TRDV1S1-TRDJ1转录本的γδ T细胞从胸腺中产生并定殖于外周组织，在那里它们被反复出现的配体选择性扩增。这种特殊情况可能与钝口螈的幼态持续状态和缓慢发育有关。在胸腺切除的钝口螈中，TRD谱系似乎与正常钝口螈不同，这表明可能发生了胸腺外γδ T细胞分化。基因表达分析显示了肠道在T细胞发育中的重要性。
