Here we imaged the exocytosis of lytic granules from human CD8(+) cytotoxic T lymphocytes using rapid total internal reflection microscopy, Lamp-1 tagged with mGFP to follow the fate of the lytic granule membrane, and granzyme A, granzyme B or serglycin tagged with mRFP to follow the fate of lytic granule cargo. Lytic granules were released by full fusion with the plasma membrane, such that the entire granule content for all three cargos visualized was released on a subsecond time scale. The behavior of GFP-Lamp-1 was, however, more complex. While it entered the plasma membrane in all cases, the extent to which it then diffused away from the site of exocytosis varied from nearly complete to highly restricted. Finally, the diffusion properties upon release of the three cargos examined put an upper limit on the size of the macromolecular complex of granzyme and serglycin that is presented to the target cell.

中文翻译：

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CD8+ 细胞毒性 T 淋巴细胞中溶解颗粒胞吐作用的成像揭示了完全融合的改良形式。


在这里，我们使用快速全内反射显微镜对来自人CD8（+）细胞毒性T淋巴细胞的裂解颗粒的胞吐作用进行成像，用mGFP标记的Lamp-1以跟踪裂解颗粒膜的命运，以及用mRFP 跟踪溶解颗粒货物的命运。溶解颗粒通过与质膜完全融合而释放，使得所有三种可视化货物的全部颗粒内容物在亚秒级时间尺度上释放。然而，GFP-Lamp-1 的行为更为复杂。虽然在所有情况下它都进入质膜，但它随后从胞吐作用位点扩散出去的程度从几乎完全到高度受限不等。最后，所检测的三种货物释放时的扩散特性对呈现给靶细胞的颗粒酶和丝甘氨酸的大分子复合物的大小设定了上限。