Hancock W W, Pleau M E, Kobzik L
Department of Medicine, University of Connecticut School of Medicine, Farmington 06032.
J Immunol. 1988 May 1;140(9):3021-5.
Recent studies have shown that normal human alveolar macrophages and blood monocytes, as well as HL-60 and U937 monocyte cell lines, newly express IL-2R after stimulation with rIFN-gamma or LPS. In addition, macrophages transiently express IL-2R in vivo during immunologically mediated diseases such as pulmonary sarcoidosis and allograft rejection. We therefore investigated in vitro factors that modulate macrophage expression of IL-2R. IL-2R were induced on normal alveolar macrophages, blood monocytes, and HL-60 cells using rIFN-gamma (24 to 48 h at 240 U/ml), and cells were cultured for an additional 12 to 24 h with rIL-2 (100 U/ml), recombinant granulocyte-macrophage CSF (rGM-CSF, 1000 U/ml), rGM-CSF plus indomethacin (2 X 10(-6) M), PGE2 (0.1 to 10 ng/ml), 1 X 10(-6) M levels of caffeine, theophylline, and dibutyryl cyclic AMP, or medium alone. IL-2R expression was quantitated by cell ELISA (HL-60 cells) or determined by immunoperoxidase staining (alveolar macrophages, blood monocytes, and HL-60 cells), using anti-Tac and other CD25 mAb. PGE production was assayed by RIA. We found greater than 95% of alveolar macrophages, monocytes, and HL-60 cells expressed IL-2R after rIFN-gamma treatment and remained IL-2R+ in the presence of IL-2R or medium alone. By comparison, greater than 95% of cells induced to express IL-2R became IL-2R- after addition of rGM-CSF, and the culture supernatants from GM-CSF-treated cells contained increased levels of PGE. This inhibition of macrophage IL-2R expression by rGM-CSF was blocked by indomethacin, and IL-2R+ macrophages became IL-2R- after addition of PGE2 alone. These findings indicate GM-CSF down-regulates IL-2R expression by human macrophages via induction of PGE synthesis. Moreover, a similar down-regulation of IL-2R expression was seen after stimulation with caffeine, theophylline, or dibutyryl cyclic AMP. Hence, GM-CSF, PGE, and other pharmacologic agents that act to increase intracellular levels of cAMP may play a modulatory role, antagonistic to that of IFN-gamma on cellular expression of IL-2R by human inflammatory macrophages in vivo.
最近的研究表明，正常人肺泡巨噬细胞和血液单核细胞，以及HL-60和U937单核细胞系，在用重组干扰素-γ（rIFN-γ）或脂多糖（LPS）刺激后会新表达白细胞介素-2受体（IL-2R）。此外，在免疫介导的疾病如肺结节病和同种异体移植排斥反应期间，巨噬细胞在体内会短暂表达IL-2R。因此，我们研究了体外调节巨噬细胞IL-2R表达的因素。使用rIFN-γ（240 U/ml，作用24至48小时）在正常肺泡巨噬细胞、血液单核细胞和HL-60细胞上诱导出IL-2R，然后将细胞与重组白细胞介素-2（rIL-2，100 U/ml）、重组粒细胞-巨噬细胞集落刺激因子（rGM-CSF，1000 U/ml）、rGM-CSF加吲哚美辛（2×10⁻⁶ M）、前列腺素E2（PGE2，0.1至10 ng/ml）、1×10⁻⁶ M浓度的咖啡因、茶碱和二丁酰环磷腺苷或单独的培养基再培养12至24小时。通过细胞酶联免疫吸附测定（ELISA）（HL-60细胞）或免疫过氧化物酶染色（肺泡巨噬细胞、血液单核细胞和HL-60细胞），使用抗Tac和其他CD25单克隆抗体（mAb）对IL-2R表达进行定量。通过放射免疫分析（RIA）测定PGE的产生。我们发现，rIFN-γ处理后，超过95%的肺泡巨噬细胞、单核细胞和HL-60细胞表达IL-2R，并且在存在IL-2R或单独培养基的情况下仍保持IL-2R阳性。相比之下，超过95%诱导表达IL-2R的细胞在加入rGM-CSF后变为IL-2R阴性，并且GM-CSF处理细胞的培养上清液中PGE水平升高。rGM-CSF对巨噬细胞IL-2R表达的这种抑制作用被吲哚美辛阻断，并且单独加入PGE2后IL-2R阳性的巨噬细胞变为IL-2R阴性。这些发现表明GM-CSF通过诱导PGE合成下调人巨噬细胞的IL-2R表达。此外，在用咖啡因、茶碱或二丁酰环磷腺苷刺激后也观察到类似的IL-2R表达下调。因此，GM-CSF、PGE和其他作用于增加细胞内cAMP水平的药物制剂可能在体内对人炎症巨噬细胞IL-2R的细胞表达发挥调节作用，与IFN-γ的作用相反。
