Shenoy A M, Sidner R A, Brahmi Z
Department of Microbiology/Immunology, Indiana University School of Medicine, Indianapolis 46202-5128.
Cell Immunol. 1993 Apr 1;147(2):294-301. doi: 10.1006/cimm.1993.1070.
Our laboratory has previously demonstrated that natural killer (NK) cell-mediated cytotoxicity is protein kinase C (PKC)-dependent and that PKC is translocated from the cytoplasm to the plasma membrane during NK cell activation. Furthermore, exposuring NK cells to a sensitive target cell for 4-6 hr at 37 degrees C rendered NK cells functionally inactive and these inactivated effector cells (i) do not turn over PI in response to K562 stimulation and (ii) lose mRNA for perforin and granzyme A and B less than 30 min after contact with K562. In this study, we first confirmed earlier findings that the interaction of sensitive target cells with human NK cells triggers an influx of extracellular calcium into NK cells. In addition, using flow cytometry we demonstrated that there was a delayed maximum uptake of extracellular calcium into functionally inactive NK cells when these cells were reexposed to fresh K562. Finally, we demonstrated that exposuring NK cells to K562 for 4 hr leads to a loss of NK cytotoxic activity and to the maximal expression of CD69.
我们实验室先前已证明，自然杀伤（NK）细胞介导的细胞毒性依赖于蛋白激酶C（PKC），并且在NK细胞激活过程中PKC从细胞质转移至质膜。此外，将NK细胞在37℃下与敏感靶细胞接触4至6小时会使NK细胞功能失活，这些失活的效应细胞（i）在受到K562刺激时不会翻转磷脂酰肌醇（PI），且（ii）在与K562接触后不到30分钟就会丢失穿孔素和颗粒酶A及B的mRNA。在本研究中，我们首先证实了早期的发现，即敏感靶细胞与人类NK细胞的相互作用会触发细胞外钙流入NK细胞。此外，通过流式细胞术我们证明，当这些功能失活的NK细胞再次暴露于新鲜的K562时，细胞外钙进入细胞的最大摄取会延迟。最后，我们证明将NK细胞暴露于K562 4小时会导致NK细胞毒性活性丧失以及CD69的最大表达。
