ACTIVATED NEUTROPHILS SECRETE STORED ALPHA 1-ANTITRYPSIN

神经弹性蛋白酶（NE）是一种有效的丝氨酸蛋白酶，主要储存在 中性粒细胞的颗粒，并在中性粒细胞活化后释放。 α-1-抗胰蛋白酶（α 1AT）是NE的主要抑制剂， 由成熟的中性粒细胞合成。在维护人权方面， 组织内稳态，我们假设中性粒细胞可能能够 储存α 1AT，从而使其可用于与 NE.免疫荧光和定量流式细胞术研究 中性粒细胞和单核细胞标记的荧光素共轭 α 1AT抗体显示细胞质中α 1AT的量更大 而不是单核细胞。放射性标记的研究 甲硫氨酸和抗α 1AT免疫沉淀分析显示， 虽然中性粒细胞和单核细胞都合成α 1AT， 新合成的细胞内α 1AT的含量在 中性粒细胞多于单核细胞。流式细胞仪分析显示， 细胞松弛素B的表面刺激的存在， N-甲酰-甲硫氨酰-亮氨酰-苯丙氨酸（fMLP），平均细胞内 刺激的中性粒细胞中α 1AT较刺激的中性粒细胞中的α 1AT降低。 静息细胞，表明储存的alpha 1AT迅速释放， 表面触发后。表面刺激的评价 中性粒细胞（放射性蛋氨酸标记和抗α 1 AT） 免疫沉淀显示α 1AT分泌增加 与静息中性粒细胞相比， α 1AT能够与NE形成复合物。因此，中性粒细胞响应 通过分泌NE及其抑制剂来刺激表面， α 1AT。这表明这些细胞具有内在的机制， 抑制NE的局部作用，NE是其最强大的蛋白水解酶。

Neutrophil elastase (NE), a potent serine protease, is stored in primary granules of neutrophils and released following neutrophil activation. Alpha-1-antitrypsin (alpha1AT), the major inhibitor of NE, is synthesized by mature neutrophils. In the context of the maintenance of tissue homeostasis, we hypothesized that neutrophils may be able to store alpha1AT, thus having it available for release concordantly with NE. Immunofluorescence and quantitative flow cytometry studies of neutrophils and monocytes labeled with fluorescein conjugated alpha1AT-antibody demonstrated larger amounts of cytoplasmic alpha1AT in neutrophils than in monocytes. Study with radioactively labeled methionine and anti-alpha1AT immunoprecipitation analysis showed that, while both neutrophils and monocytes synthesize alpha1AT, the proportion of newly synthesized intracellular alpha1AT was much higher in neutrophils than in monocytes. Flow cytometric analysis showed that in the presence of surface stimulation with cytochalasin B followed by N-formyl-methionyl-leucyl-phenylalanine (fMLP), mean intracellular alpha1AT was decreased in stimulated neutrophils compared with that in resting cells, suggesting that the stored alpha1AT was rapidly released following surface triggering. Evaluation of surface stimulated neutrophils by radioactive methionine labeling and anti-alpha1AT immunoprecipitation demonstrated increased secretion of alpha1AT compared to that of resting neutrophils, with some of the secreted alpha1AT capable of forming complexes with NE. Thus, neutrophils respond to surface stimulation by secreting not only NE but also its inhibitor, alpha1AT. This suggests that these cells have an inherent mechanism for dampening the local effects of NE, its most powerful proteolytic enzyme.