Vollger L W, Uittenbogaart C H
Department of Microbiology & Immunology, Center for Interdisciplinary Research in Immunologic Diseases (CIRID), UCLA School of Medicine 90024-1747.
Cytokine. 1993 Mar;5(2):157-68. doi: 10.1016/1043-4666(93)90055-a.
IL-7 has been shown to support the proliferation of several cell types including human and murine thymocytes. We have investigated the influence of IL-7 on human thymocyte growth and maturation. In a serum-free culture system, recombinant human interleukin-7 (IL-7) (200 U/ml) stimulated nylon wool purified human thymocytes to express a mature phenotype. IL-7 promoted the generation of a population of large thymocytes which expressed high density CD3, CD4 and/or CD8, and high density CD45RA after 10 to 14 days in culture. The induction of CD45RA was not a transient event, since large CD45RA+ cells remained "bright" CD45RA+ up to 12 days after IL-7 was removed from cultures. IL-7 did support thymocyte proliferation. However, the IL-7-induced generation of large CD45RA+ thymocytes was not due to proliferation of a small subset because large CD45RA+ thymocytes also appeared in the presence of proliferation inhibitors. In order to identify IL-7-responsive thymocyte subsets, highly purified CD45RA- subsets at distinct stages of maturation were tested. CD3-, "dim" CD3+ and "bright" CD3+ subsets each responded to IL-7 with de novo expression of CD45RA. These data provide evidence that IL-7 supports phenotypic changes in both mature and immature subsets of human thymocytes, and indicate that IL-7 may play an important role in T cell development in the thymus.
白细胞介素-7（IL-7）已被证明可支持包括人类和小鼠胸腺细胞在内的多种细胞类型的增殖。我们研究了IL-7对人类胸腺细胞生长和成熟的影响。在无血清培养系统中，重组人白细胞介素-7（IL-7）（200 U/ml）刺激经尼龙毛纯化的人类胸腺细胞表达成熟表型。培养10至14天后，IL-7促进了一群大胸腺细胞的生成，这些细胞表达高密度的CD3、CD4和/或CD8以及高密度的CD45RA。CD45RA的诱导不是一个短暂事件，因为在从培养物中去除IL-7后长达12天，大的CD45RA+细胞仍保持“明亮”的CD45RA+。IL-7确实支持胸腺细胞增殖。然而，IL-7诱导产生大的CD45RA+胸腺细胞并非由于一小部分细胞的增殖，因为在存在增殖抑制剂的情况下也出现了大的CD45RA+胸腺细胞。为了鉴定对IL-7有反应的胸腺细胞亚群，对处于不同成熟阶段的高度纯化的CD45RA-亚群进行了测试。CD3-、“弱阳性”CD3+和“强阳性”CD3+亚群均对IL-7作出反应，重新表达CD45RA。这些数据提供了证据，表明IL-7支持人类胸腺细胞成熟和未成熟亚群的表型变化，并表明IL-7可能在胸腺中T细胞发育中起重要作用。
