Malawista S E, De Boisfleury Chevance A
J Cell Biol. 1982 Dec;95(3):960-73. doi: 10.1083/jcb.95.3.960.
We examined the formation of motile, chemotactically active, anucleate fragments from human blood polymorphonuclear leukocytes (PMN, granulocytes), induced by the brief application of heat. These granule-poor fragments are former protopods (leading fronts, lamellipodia) that become uncoupled from the main body of the cell and leave it, at first with a connecting filament that breaks and seals itself. The usual random orientation of such filaments can be controlled by preorientation of cells in a gradient of the chemotactic peptide, N-formylmethionylleucylphenylalanine (F-Met-Leu-Phe) (2x10(-9) M- 1x10(-8)). Cytochalsin B, 2.5-5 mug/ml, prevents fragment formation; colchicine, 10(-5) M, does not. In scanning electron micrographs, fragments are ruffled and the cell body rounded up and rather smooth. In transmission electron micrographs, fragments contain microfilaments but lack centrioles and microtubules. Like intact cells, both bound and free fragments can respond chemotactically to an erythrocyte destroyed by laser microirradiation (necrotaxis); the free, anucleate fragments may do so repeatedly, even after having been held overnight at ambient temperatures. We propse the name cytokineplast for the result of this self-purification of motile apparatus. The exodus of the motile machinery from the granulocyte requires anchoring of the bulk of the cell to glass and uncoupling, which may involve heat-induced dysfunction of the centrosome. In ultrastructural studies of the centrosomal region after heat, centriolar structure remains intact, but pericentriolar osmiophilic material appears condensed, and microtubules are sparse. These changes are found in all three blood cell types examined: PMN, eosinophil, and monocyte. Of these, the first two make fragments under our conditions; the more sluggish monocyte does not. Uncoupling is further linked to centrosomal dysfunction by the observation that colchicines-treated granulocytes (10(-5)M, to destroy the centrosome's efferent arm) make fragments after less heat than controls. If motive force and orientation are specified mainly from the organelle-excluding leading front, then endoplasmic streaming in PMN is a catch-up phenomenon, and microtubules do not provide the vector of locomotion but rather stabilize and orient the "baggage" (nucleus, granuloplasm)-i.e., they prevent fishtailing. Moreover, constraints emanating from the centrosome may now be extended to include, maintenance of the motile machinery as an integral part of the cell.
我们研究了通过短暂加热诱导人血多形核白细胞（PMN，粒细胞）形成有运动能力、具有趋化活性的无核碎片的过程。这些颗粒较少的碎片是先前的原生质足（前沿、片状伪足），它们与细胞主体分离并离开，最初带有一条会断裂并自行封闭的连接细丝。这种细丝通常的随机取向可通过在趋化肽N-甲酰甲硫氨酰亮氨酰苯丙氨酸（F-Met-Leu-Phe）（2×10⁻⁹ M - 1×10⁻⁸）梯度中对细胞进行预取向来控制。2.5 - 5微克/毫升的细胞松弛素B可防止碎片形成；10⁻⁵ M的秋水仙碱则不能。在扫描电子显微镜图像中，碎片表面呈波纹状，细胞主体变圆且相当光滑。在透射电子显微镜图像中，碎片含有微丝，但缺乏中心粒和微管。与完整细胞一样，结合的和游离的碎片都能对激光微照射破坏的红细胞产生趋化反应（坏死趋化）；游离的无核碎片甚至在室温下放置过夜后仍可能反复产生这种反应。我们提议将这种运动装置自我净化的产物命名为细胞因子质体。粒细胞中运动机制的外流需要细胞大部分附着在玻璃上并分离，这可能涉及中心体的热诱导功能障碍。在对加热后的中心体区域进行超微结构研究时，中心粒结构保持完整，但中心粒周围的嗜锇物质似乎浓缩，微管稀少。在所有检测的三种血细胞类型中都发现了这些变化：PMN、嗜酸性粒细胞和单核细胞。其中，前两种在我们的条件下会形成碎片；较为迟缓的单核细胞则不会。通过观察发现，用秋水仙碱处理的粒细胞（10⁻⁵ M，以破坏中心体的传出臂）在比对照更少的加热后就会形成碎片，这进一步将分离与中心体功能障碍联系起来。如果动力和方向主要由不包括细胞器的前沿决定，那么PMN中的内质流是一种追赶现象，微管不提供运动的矢量，而是稳定并定向“行李”（细胞核、颗粒质），即它们防止细胞尾部摆动。此外，可以推断出中心体产生的限制现在可能扩展到包括将运动机制维持为细胞的一个组成部分。
