Young J D, Ko S S, Cohn Z A
Proc Natl Acad Sci U S A. 1984 Sep;81(17):5430-4. doi: 10.1073/pnas.81.17.5430.
The concentration of cytosolic free calcium, [Ca2+]i, was measured in J774 mouse macrophages by use of the fluorescent indicator quin-2. Resting [Ca2+]i was 87 nM. Addition of a number of specific ligands to the immunoglobulin gamma 2b/gamma 1 Fc receptor resulted in a transient increase in [Ca2+]i, the magnitude of which depended on the extent of receptor aggregation. Monovalent ligands gave only a small Ca2+ signal but blocked cell response to subsequent addition of multivalent ligands. Incubation with antibody-coated erythrocytes raised macrophage [Ca2+]i to micromolar levels. [Ca2+]i changes were only partially inhibited by the absence of external Ca2+, suggesting the release of Ca2+ from internal stores in addition to an influx of external Ca2+. These internal stores were not limited to mitochondria. An optimal range of [Ca2+]i was required for phagocytosis. Buffering [Ca2+]i with quin-2 and treating cells with quinine in the absence of external Ca2+ resulted in inhibition of phagocytosis. Increasing [Ca2+]i to micromolar levels with the calcium ionophore A23187 also resulted in similar inhibitory effects. We suggest the involvement of localized cytosolic Ca2+ gradients in generating the signals necessary for phagocytosis.
利用荧光指示剂喹啉-2，在J774小鼠巨噬细胞中测量了胞质游离钙浓度[Ca2+]i。静息[Ca2+]i为87 nM。向免疫球蛋白γ2b/γ1 Fc受体添加多种特异性配体，导致[Ca2+]i瞬时升高，其幅度取决于受体聚集程度。单价配体仅产生较小的Ca2+信号，但阻断了细胞对随后添加的多价配体的反应。与抗体包被的红细胞孵育使巨噬细胞[Ca2+]i升高至微摩尔水平。[Ca2+]i的变化仅部分受到细胞外Ca2+缺失的抑制，这表明除了细胞外Ca2+内流外，细胞内储存的Ca2+也有释放。这些细胞内储存不限于线粒体。吞噬作用需要[Ca2+]i的最佳范围。在没有细胞外Ca2+的情况下，用喹啉-2缓冲[Ca2+]i并使用奎宁处理细胞，导致吞噬作用受到抑制。用钙离子载体A23187将[Ca2+]i增加到微摩尔水平也产生了类似的抑制作用。我们认为局部胞质Ca2+梯度参与产生吞噬作用所需的信号。
