Lundqvist-Gustafsson H, Gustafsson M, Dahlgren C
Division of Pathology II, Faculty of Health Sciences, Linköping University, Sweden.
Cell Calcium. 2000 Jun;27(6):353-62. doi: 10.1054/ceca.2000.0130.
An increase in cytosolic Ca(2+)concentration periphagosomally is critical for phagolysosomal formation and neutrophil elimination of microbes. The Ca(2+)increase could be achieved through release of Ca(2+)from mobilized intracellular stores. Alternatively, Ca(2+)that passively enter the phagosome during phagocytosis could be provided by the phagosome. Intraphagosomal Ca(2+)changes in single human neutrophils was measured during phagocytosis of serum opsonized Fura-2-conjugated zymosan particles, using a digital image processing system for microspectrofluorometry. A decrease in phagosomal Ca(2+)down to nanomolar concentrations was seen within minutes following phagosomal closure. Blockage of plasma membrane Ca(2+)channels by econazole abolished this decrease. The fluorescence properties of Fura-2 zymosan were retained after phagocytosis and stable to pH changes, reactive oxygen species, and proteolytic enzymes. We suggest that Ca(2+)ions present in the phagosome enter the cell cytosol through Ca(2+)channels in the phagosomal membrane, achieving a localized Ca(2+)rise that is important for phagosome processing.
吞噬体周围胞质Ca(2+)浓度的增加对于吞噬溶酶体的形成以及中性粒细胞清除微生物至关重要。Ca(2+)的增加可通过动员细胞内储存库释放Ca(2+)来实现。另外，吞噬过程中被动进入吞噬体的Ca(2+)可由吞噬体提供。在吞噬血清调理的Fura-2偶联酵母聚糖颗粒的过程中，使用数字图像处理系统进行显微分光荧光测定，测量了单个人类中性粒细胞内吞噬体Ca(2+)的变化。吞噬体封闭后数分钟内，吞噬体Ca(2+)浓度降至纳摩尔水平。益康唑对质膜Ca(2+)通道的阻断消除了这种降低。Fura-2酵母聚糖的荧光特性在吞噬后得以保留，并且对pH变化、活性氧和蛋白水解酶稳定。我们认为，吞噬体中存在的Ca(2+)离子通过吞噬体膜上的Ca(2+)通道进入细胞质溶胶，实现局部Ca(2+)升高，这对吞噬体处理很重要。
