Seddiki N, Ben Younes-Chennoufi A, Benjouad A, Saffar L, Baumann N, Gluckman J C, Gattegno L
Laboratoire de Biologie Cellulaire, Université Paris-Nord, Bobigny, France.
AIDS Res Hum Retroviruses. 1996 May 20;12(8):695-703. doi: 10.1089/aid.1996.12.695.
The membrane glycolipids galactosylceramide (GalCer) and sulfatide (SGalCer) have been reported to act as receptors of human immunodeficiency virus (HIV) on CD4- cell lines. We show here that these glycolipids are present on CD4+ cells purified from human blood and on in vitro-differentiated monocyte-derived macrophages (MDMs). We investigated the role they could play in HIV infection. Glycolipids of MDMs were characterized at the molecular level by immunolabeling and thin-layer chromatography immune overlay, using a panel of human-, rabbit-, or murine-specific antibodies. GalCer and SGalCer were expressed at the surface of MDMs as assessed by indirect immunofluorescence and flow cytometry analysis, and they could be characterized with specific antibodies in the cellular glycolipid extracts in addition to GM1, GM3, and GD1b gangliosides. Recombinant 125-I-labeled gp160 specifically bound to GalCer, SGalCer, GM1, and GM3 as well as to phospholipids (phosphatidylethanolamine and phosphatidylserine) from MDM extracts. Anti-SGalCer monoclonal antibodies (MAbs), but not anti-GalCer antibodies, entailed limited (30-40%) but significant inhibition of gp160 binding to MDMs. However, the four human anti-SGalCer MAbs and the three murine or rabbit ant-GalCer antibodies tested did not inhibit HIV infection of MDMs, in contrast to CD4 antibody anti-Leu3a tested in parallel. These findings suggests that although HIV envelope glycoprotein can bind to SGalCer and GalCer from CD4+ MDM extracts, these glycolipids do not apparently act as HIV coreceptors nor are they involved in HIV infection of these cells.
据报道，膜糖脂半乳糖基神经酰胺（GalCer）和硫苷脂（SGalCer）可作为人类免疫缺陷病毒（HIV）在CD4⁺细胞系上的受体。我们在此表明，这些糖脂存在于从人血液中纯化的CD4⁺细胞以及体外分化的单核细胞衍生巨噬细胞（MDM）上。我们研究了它们在HIV感染中可能发挥的作用。通过使用一组人、兔或鼠特异性抗体，通过免疫标记和薄层色谱免疫印迹在分子水平上对MDM的糖脂进行了表征。通过间接免疫荧光和流式细胞术分析评估，GalCer和SGalCer在MDM表面表达，除了GM1、GM3和GD1b神经节苷脂外，它们还可以在细胞糖脂提取物中用特异性抗体进行表征。重组¹²⁵I标记的gp160特异性结合GalCer、SGalCer、GM1和GM3以及来自MDM提取物的磷脂（磷脂酰乙醇胺和磷脂酰丝氨酸）。抗SGalCer单克隆抗体（MAb）而非抗GalCer抗体对gp160与MDM的结合产生了有限（30 - 40%）但显著的抑制作用。然而，与平行测试的抗CD4抗体抗Leu3a相反，所测试的四种人抗SGalCer MAb以及三种鼠或兔抗GalCer抗体均未抑制MDM的HIV感染。这些发现表明，尽管HIV包膜糖蛋白可以与CD4⁺MDM提取物中的SGalCer和GalCer结合，但这些糖脂显然既不作为HIV共受体起作用，也不参与这些细胞的HIV感染。
