Choy M Y, Manyonda I T
Department of Cellular and Molecular Sciences, St George's Hospital Medical School, London, UK.
Hum Reprod. 1998 Oct;13(1O):2941-9. doi: 10.1093/humrep/13.10.2941.
It has been suggested previously that phagocytic activity in the human placenta is confined to cells of the macrophage lineage. However, earlier studies were hampered by the paucity and poor viability of cells inherent in primary trophoblast cell cultures, contamination by other cell types which themselves have phagocytic activity, lack of reliable markers of trophoblasts, and by limitations of methods available to demonstrate unequivocally the internalization of particulate material. We have overcome these limitations by using: (i) DNA transfection to provide unlimited supplies of pure trophoblast cell lines; (ii) human placental lactogen as a marker unique to trophoblast; and (iii) confocal microscopy to demonstrate unequivocally the intracellular locality of phagocytosed material. We found that both untransfected primary culture extravillous trophoblast cells, as well as the cell lines, had the capacity to phagocytose sheep red blood cells, Staphylococcus aureus and baker's yeast cells, and that this activity was inhibited by cytochalasin B and by culture at 4 degrees C. Phagocytic activity in trophoblast cells was less avid than that seen in a professional phagocyte. In physiological and pathological situations where tissue remodelling occurs, such as the rapid turnover in the periodontal ligament or during inflammation, epithelial cells and other cells that are not considered professional phagocytes actively phagocytose components of the extracellular matrix. We postulate that phagocytosis by human trophoblasts may play an important role in the extensive tissue remodelling that occurs during trophoblastic invasion of the decidua.
此前有人提出，人类胎盘中的吞噬活性仅限于巨噬细胞谱系的细胞。然而，早期研究受到原代滋养层细胞培养中细胞数量稀少且活力不佳、被自身具有吞噬活性的其他细胞类型污染、缺乏可靠的滋养层标记物以及用于明确证明颗粒物质内化的现有方法的局限性等因素的阻碍。我们通过以下方法克服了这些局限性：（i）DNA转染以提供无限量的纯滋养层细胞系；（ii）人胎盘催乳素作为滋养层特有的标记物；（iii）共聚焦显微镜以明确证明吞噬物质的细胞内定位。我们发现，未转染的原代培养绒毛外滋养层细胞以及细胞系都有吞噬绵羊红细胞、金黄色葡萄球菌和面包酵母细胞的能力，并且这种活性受到细胞松弛素B和4℃培养的抑制。滋养层细胞中的吞噬活性不如专业吞噬细胞中的活性强烈。在发生组织重塑的生理和病理情况下，例如牙周韧带的快速更新或炎症期间，上皮细胞和其他不被视为专业吞噬细胞的细胞会积极吞噬细胞外基质的成分。我们推测，人类滋养层细胞的吞噬作用可能在滋养层侵入蜕膜期间发生的广泛组织重塑中起重要作用。
