Crestani B, Cornillet P, Dehoux M, Rolland C, Guenounou M, Aubier M
Institut National de la Santé et de la Recherche Médicale INSERM U 408, Faculté Xavier Bichat, Paris, France.
J Clin Invest. 1994 Aug;94(2):731-40. doi: 10.1172/JCI117392.
The aims of this study were (a) to determine if rat alveolar type II (ATII) cells and human pulmonary epithelial-derived cells (A549 cell line) could generate IL-6 in vitro, (b) to characterize the cytokine regulation of IL-6 gene and protein expression in these cells, and (c) to detect the in vivo expression of immunoreactive IL-6 by human ATII cells. Rat ATII cells in primary culture secreted bioactive IL-6 and immunostained with an anti-IL-6 antiserum. Spontaneous IL-6 secretion by rat ATII cells amounted to 5,690 +/- 770 pg/ml/10(6) cells (n = 12) and was fivefold higher than spontaneous rat alveolar macrophages IL-6 secretion (1,052 +/- 286 pg/ml/10(6) cells, n = 8, P = 0.001). Rat alveolar macrophage conditioned media (CM) increased IL-6 secretion by rat ATII cells through the effect of IL-1 and TNF. IL-6 gene expression and IL-6 secretion by A549 cells was induced by IL-1 beta, TNF alpha, and by human alveolar macrophages and THP1 cells CM. Induction was abolished when CM were preincubated with anti-IL-1 beta and anti-TNF alpha antibody. The combination of IFN gamma and LPS induced the expression of IL-6 mRNA by A549 cells whereas LPS alone had no effect. Immunohistochemical staining evidenced the expression of immunoreactive IL-6 by hyperplastic ATII cells in fibrotic human lung, a condition in which alveolar macrophages are known to be activated. ATII cells in normal human lung did not express immunoreactive IL-6. Our findings demonstrate that ATII cells may be an important source of IL-6 in the alveolar space thereby participating to the regulation of the intra-alveolar immune response.
(a) 确定大鼠肺泡Ⅱ型（ATII）细胞和人肺上皮来源细胞（A549细胞系）是否能在体外产生白细胞介素-6（IL-6）；(b) 阐明这些细胞中IL-6基因和蛋白表达的细胞因子调控机制；(c) 检测人ATII细胞在体内免疫反应性IL-6的表达情况。原代培养的大鼠ATII细胞分泌生物活性IL-6，并能用抗IL-6抗血清进行免疫染色。大鼠ATII细胞自发分泌的IL-6量为5,690±770 pg/ml/10⁶细胞（n = 12），比大鼠肺泡巨噬细胞自发分泌的IL-6量高5倍（1,052±286 pg/ml/10⁶细胞，n = 8，P = 0.001）。大鼠肺泡巨噬细胞条件培养基（CM）通过IL-1和肿瘤坏死因子（TNF）的作用增加大鼠ATII细胞的IL-6分泌。A549细胞的IL-6基因表达和IL-6分泌受到IL-1β、TNFα以及人肺泡巨噬细胞和THP1细胞CM的诱导。当CM与抗IL-1β和抗TNFα抗体预孵育时，诱导作用消失。干扰素γ（IFNγ）和脂多糖（LPS）的组合诱导A549细胞IL-6 mRNA的表达，而单独的LPS则无此作用。免疫组织化学染色证明，在人肺纤维化时增生的ATII细胞表达免疫反应性IL-6，已知在这种情况下肺泡巨噬细胞被激活。正常人肺中的ATII细胞不表达免疫反应性IL-6。我们的研究结果表明，ATII细胞可能是肺泡腔中IL-6的重要来源，从而参与肺泡内免疫反应的调节。
