Monoclonal antibodies against oxidized low-density lipoprotein bind to apoptotic cells and inhibit their phagocytosis by elicited macrophages:: Evidence that oxidation-specific epitopes mediate macrophage recognition
Monoclonal antibodies against oxidized low-density lipoprotein bind to apoptotic cells and inhibit their phagocytosis by elicited macrophages:: Evidence that oxidation-specific epitopes mediate macrophage recognition
复制标题
DOI：
10.1073/pnas.96.11.6353
复制
发表时间：
1999-05-25
影响因子：
11.1
通讯作者：
Witztum, JL
中科院分区：
文献类型：
--
作者：
Chang, MK;Bergmark, C;Witztum, JL
细胞凋亡被认为是多细胞生物体中正常细胞稳态的重要因素。虽然我们对调节凋亡的分子事件的认识有了很大的进展，但对负责凋亡细胞识别和吞噬的吞噬细胞上的受体或介导这种识别的凋亡细胞上的配体知之甚少。凋亡细胞的氧化应激增加，氧化低密度脂蛋白（OxLDL）与凋亡细胞竞争巨噬细胞结合的观察建议的假设，OxLDL和凋亡细胞共享氧化修饰的部分在其表面上，作为巨噬细胞识别的配体。为了验证这一假设，我们使用了鼠单克隆自身抗体结合氧化低密度脂蛋白上的氧化特异性表位。特别地，抗体EO 6和EO 3识别氧化磷脂，包括1-棕榈酰2-（5-氧代戊酰）磷脂酰胆碱（POVPC），抗体EO 12和EO 14识别丙二酰去赖氨酸，如在丙二酰去-LDL中。使用FAGS分析，我们证明了这些EO抗体中的每一个与凋亡细胞结合，但不与正常细胞结合，而对照IgM抗体不与凋亡细胞结合。共聚焦显微镜显示凋亡细胞上氧化特异性表位的细胞表面表达。此外，这些抗体中的每一种都抑制了诱导的腹膜巨噬细胞对凋亡细胞的吞噬作用，就像OxLDL一样。此外，POVPC与BSA的加合物也有效地阻止了吞噬作用。这些数据表明，凋亡细胞表达氧化特异性表位，包括氧化磷脂，在他们的细胞表面，这些作为识别和诱导巨噬细胞吞噬的配体。
Apoptosis is recognized as important for normal cellular homeostasis in multicellular organisms. Although there have been great advances in our knowledge of the molecular events regulating apoptosis, much less is known about the receptors on phagocytes responsible for apoptotic cell recognition and phagocytosis or the ligands on apoptotic cells mediating such recognition. The observations that apoptotic cells are under increased oxidative stress and that oxidized low-density lipoprotein (OxLDL) competes with apoptotic cells for macrophage binding suggested the hypothesis that both OxLDL and apoptotic cells share oxidatively modified moieties on their surfaces that serve as ligands for macrophage recognition. To test this hypothesis, we used murine monoclonal autoantibodies that bind to oxidation-specific epitopes on OxLDL. in particular, antibodies EO6 and EO3 recognize oxidized phospholipids, including l-palmitoyl 2-(5-oxovaleroyl) phosphatidylcholine (POVPC), and antibodies EO12 and EO14 recognize malondialdehydelysine, as in malondialdehyde-LDL. Using FAGS analysis, we demonstrated that each of these EO antibodies bound to apoptotic cells but not to normal cells, whereas control IgM antibodies did not. Confocal microscopy demonstrated cell-surface expression of the oxidation-specific epitopes on apoptotic cells. Furthermore, each of these antibodies inhibited the phagocytosis of apoptotic cells by elicited peritoneal macrophages, as did OxLDL. In addition, an adduct of POVPC with BSA also effectively prevented phagocytosis. These data demonstrate that apoptotic cells express oxidation-specific epitopes-including oxidized phospholipids-on their cell surface, and that these serve as ligands for recognition and phagocytosis by elicited macrophages.