Anti-endothelial cell antibodies from lupus patients bind to apoptotic endothelial cells promoting macrophage phagocytosis but do not induce apoptosis.
Anti-endothelial cell antibodies from lupus patients bind to apoptotic endothelial cells promoting macrophage phagocytosis but do not induce apoptosis.
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DOI：
10.1093/rheumatology/keh633
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发表时间：
2005-07
期刊：
影响因子：
5.5
通讯作者：
Julie M. Williams;R. Colman;C. Brookes;C. O. Savage;Lorraine Harper
中科院分区：
文献类型：
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作者：
Julie M. Williams;R. Colman;C. Brookes;C. O. Savage;Lorraine Harper
目的抗内皮细胞抗体（AECA）可诱导细胞凋亡。我们研究了这些自身抗体诱导的凋亡及其参与凋亡细胞的清除。方法分离自活动期系统性红斑狼疮（SLE）患者的AECA，与人脐静脉内皮细胞（HUVECs）共同孵育。使用基于细胞的ELISA鉴定AECA阳性血清。通过形态学和磷脂酰丝氨酸外化，使用流式细胞术与异硫氰酸荧光素（FITC）结合的膜联蛋白V。流式细胞术用于研究AECA结合凋亡细胞使用FITC结合的抗人免疫球蛋白G（IgG）。凋亡内皮细胞用红色染料（PKH 26）染色，并与巨噬细胞共培养，在相差显微镜下观察吞噬作用。结果与正常IgG（nIgG）相比，SLE患者的AECA在任何时间点均未诱导细胞凋亡，如形态学（24 h，P = 0.167）或磷脂酰丝氨酸外化（24 h，P = 0.098）评估。然而，AECA与凋亡内皮细胞的结合增加（48.8 +/- 11.9，与新鲜分离细胞的25.8 +/- 6.7%相比，P< 0.001）。当用nIgG调理的细胞与AECA（34.8 +/-3.4%n = 5，P = 0.01）相比时，这些调理的内皮细胞显示出更大的巨噬细胞吞噬作用（平均吞噬指数24.9 +/- 4.5%）。结论AECA与凋亡内皮细胞结合，但不诱导内皮细胞凋亡。通过AECA对凋亡内皮细胞的调理作用增加巨噬细胞吞噬作用，AECA是细胞清除的促炎机制。
OBJECTIVE Anti-endothelial cell antibodies (AECA) have been reported to induce apoptosis. We investigated the induction of apoptosis by these autoantibodies and their involvement in the removal of apoptotic cells. METHODS AECA isolated from patients with active systemic lupus erythematosus (SLE) were incubated with human umbilical vein endothelial cells (HUVECs). AECA-positive sera were identified using a cell-based ELISA. Apoptosis was measured by morphology and phosphatidylserine externalization using flow cytometry with fluorescein isothiocyanate (FITC)-conjugated annexin V. Flow cytometry was used to investigate AECA binding to apoptotic cells using FITC-conjugated anti-human immunoglobulin G (IgG). Apoptotic endothelial cells were stained with a red dye (PKH26) and co-cultured with macrophages, and phagocytosis was visualized under phase contrast microscopy. RESULTS AECA from patients with SLE did not induce apoptosis compared with normal IgG (nIgG) at any time point, as assessed by morphology (at 24 h, P = 0.167) or phosphatidylserine externalization (at 24 h, P = 0.098). However, there was increased binding of AECA to apoptotic endothelial cells (48.8 +/- 11.9 compared with 25.8 +/- 6.7% AECA binding to freshly isolated cells, P< 0.001). These opsonized endothelial cells showed greater phagocytosis by macrophages (mean phagocytic index 24.9 +/- 4.5%) when cells opsonized with nIgG were compared with AECA (34.8 +/- 3.4% n = 5, P = 0.01). CONCLUSION In conclusion, AECA bind to apoptotic endothelial cells but do not induce endothelial cell apoptosis. Macrophage phagocytosis is increased by opsonization of apoptotic endothelial cells by AECA, a proinflammatory mechanism of cell removal.