Parnaik R, Raff M C, Scholes J
Medical Research Council Laboratory for Molecular Cell Biology, Medical Research Council Developmental Neurobiology Programme, University College London, London, WC1E 6BT, UK.
Curr Biol. 2000 Jul 13;10(14):857-60. doi: 10.1016/s0960-9822(00)00598-4.
Both professional and non-professional phagocytes [1] participate in clearing the massive numbers of cells that undergo apoptosis during animal development [2], but it is not known how they divide this task. Using time-lapse recordings of cells in culture, we show that professional phagocytes (brain macrophages or microglia) are highly motile, ingest apoptotic cells immediately, and digest them quickly. Non-professionals such as BHK and lens epithelial cells are sessile, often recognize apoptotic cells as soon as they die by showing characteristic palpating movements, but delay ingestion until several hours later. By pre-ageing apoptotic cells, we show that this delay is because the apoptotic cells must undergo further changes before non-professionals can ingest them. The difference was also apparent in vivo, using immunofluorescence and electron microscopy of the developing central nervous system. This arrangement favours prompt clearance by professionals if present in adequate numbers; if they are scarce, however, non-professional bystanders will reluctantly clear the apoptotic cells.
专业吞噬细胞和非专业吞噬细胞[1]都参与清除动物发育过程中大量发生凋亡的细胞[2]，但尚不清楚它们如何分工完成这项任务。通过对培养细胞进行延时记录，我们发现专业吞噬细胞（脑巨噬细胞或小胶质细胞）具有高度的运动性，能立即摄取凋亡细胞并迅速将其消化。像BHK细胞和晶状体上皮细胞这样的非专业吞噬细胞是静止不动的，通常在凋亡细胞一死亡时就能通过表现出特征性的触诊运动识别它们，但会延迟摄取，直到数小时后才进行。通过对凋亡细胞进行预先老化处理，我们发现这种延迟是因为凋亡细胞在非专业吞噬细胞摄取它们之前必须经历进一步的变化。在发育中的中枢神经系统中使用免疫荧光和电子显微镜观察，这种差异在体内也很明显。如果有足够数量的专业吞噬细胞，这种安排有利于它们迅速清除凋亡细胞；然而，如果专业吞噬细胞数量稀少，非专业的旁观者细胞就会勉强清除凋亡细胞。
