Human follicular dendritic cells and vascular cells produce interleukin-7: A potential role for interleukin-7 in the germinal center reaction
Human follicular dendritic cells and vascular cells produce interleukin-7: A potential role for interleukin-7 in the germinal center reaction
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DOI：
10.1002/eji.1830261040
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发表时间：
1996-10-01
影响因子：
5.4
通讯作者：
Gerdes, J
中科院分区：
文献类型：
--
作者：
Kroncke, R;Loppnow, H;Gerdes, J
白细胞介素-7（IL-7）长期以来被认为是淋巴细胞发育中的一种有效生长因子。然而，最近在体外获得的数据揭示了这种细胞因子的额外功能，例如IL-7影响细胞毒性T细胞和NK细胞的产生，并且在较高浓度下，以类似于细菌脂多糖的方式激活单核细胞。此外，人扁桃体B细胞能够在IL-7刺激和B细胞受体交联后增殖。考虑到IL-7对B细胞增殖的后一种作用，我们研究了人体免疫系统的哪些细胞在体内表达IL-7。扁桃体细胞的mRNA表达进行了分析，使用逆转录聚合酶链反应，蛋白质表达进行了评估，通过免疫组化染色的冷冻切片。在从人扁桃体分离的多种不同免疫细胞类型中，只有滤泡树突状细胞（FDC）表达特异性IL-7产物，而B和T细胞始终呈阴性。扁桃体切片的免疫组织化学染色显示免疫反应性IL-7蛋白在FDC上的表达，并且在口腔粘膜和血管内皮细胞中也可以检测到显著的表达。对于后者，我们也可以证明在原代培养细胞中的mRNA表达。根据先前的发现，IL-7可以作为诱导扁桃体B细胞增殖的共刺激物，这些数据表明IL-7在生发中心反应中的作用。很容易推测，FDC可能在扁桃体中的B细胞发育中起调节细胞的作用，因为上皮养育细胞被认为控制胸腺中的T细胞发育。
Interleukin-7 (IL-7) has long been known as a potent growth factor in lymphocyte development. However, recent data obtained in vitro revealed additional functions for this cytokine, e.g. IL-7 influences the generation of cytotoxic T cells and NK cells, and in higher concentrations, activates monocytes in a manner similar to bacterial lipopolysaccharide. Furthermore, human tonsillar B cells are able to proliferate upon stimulation by IL-7 and cross-linking of the B cell receptor. Considering the latter role of IL-7 for B cell proliferation, we investigated which cells of the human immune system express IL-7 in vivo. mRNA expression of tonsillar cells was analyzed using the reverse transcription polymerase chain reaction, and protein expression was assessed by immunohistochemical staining of frozen sections. Among a variety of different immune cell types isolated from human tonsils, only follicular dendritic cells (FDC) expressed specific IL-7 products, whereas B and T cells were consistently negative. Immunohistochemical staining of tonsillar sections revealed the expression of immunoreactive IL-7 protein on FDC, and a pronounced expression could also be detected in oral mucosa and vascular endothelial cells. For the latter, we could also demonstrate mRNA expression in primary cultured cells. In light of the previous finding that IL-7 can act as a co-stimulus for the induction of proliferation in tonsillar B cells, these data suggest a role of IL-7 in the germinal center reaction. It is tempting to speculate that FDC may function as regulatory cells in B cell development in the tonsil, as epithelial nurse cells are thought to govern T cell development in the thymus.