Interactions of radiolabeled tuftsin with human neutrophils.
Interactions of radiolabeled tuftsin with human neutrophils.
复制标题
放射性标记的促吞噬素与人中性粒细胞的相互作用。
DOI：
10.1016/0161-5890(78)90125-6
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
H. Fudenberg
中科院分区：
文献类型：
--
作者：
Raghavan M.G. Nair;Raghavan M.G. Nair;Bruce E Ponce;H. Fudenberg
在分子的C端或N端用[14C]或[125I]标记吞噬刺激多肽Tuftsin，并在体外研究了相应的放射性标记Tuftsin与人中性粒细胞、淋巴细胞或单核细胞的特异性相互作用。培养上清液中中性粒细胞结合72.2±10.3%的14C或125I标记的Tuftsin。当标记被结合在N-末端部分时，结合减少到10%，表明N-末端是活性所必需的。淋巴细胞和单核细胞也有标记的tuftsin的特异结合部位，但结合率较低。差异不显著。将不同数量的未标记Tuftsin添加到标记的Tuftsin-中性粒细胞复合体中，表明对细胞上的结合位置进行了定量竞争。中性粒细胞与鸡抗凝血素预先孵育取消了结合。这些研究表明，中性粒细胞、淋巴细胞和单核细胞具有吞噬细胞刺激肽的受体位置。白细胞激肽酶在中性粒细胞的作用下，从白细胞激肽中裂解并产生Tuftsin，这是吞噬过程中的一个重要事件。我们目前的工作证明，中性粒细胞上的四肽Tuftsin的受体位置为阐明吞噬-刺激机制提供了有价值的联系。淋巴细胞和单核细胞上存在相似的Tuftsin结合位点，这表明这些细胞群在吞噬过程中的一系列事件中也可能起到作用。脾切除或有频繁感染的脾患者可能存在这些细胞上的Fc受体缺陷，或者这些患者可能缺乏特定的免疫球蛋白亚类和/或从其裂解Tuftsin的特定酶。
Tuftsin, the phagocytosis-stimulating peptide, was labeled with [14C] or [125I] at the C-terminal or N-terminal portions of the molecule and the specific interactions of the corresponding radiolabeled tuftsin with human neutrophils, lymphocytes, or monocytes were studiedin vitro. Neutrophils bound 72.2 ± 10.3%, of the14C- or125I-labeled tuftsin in the incubation medium. When the label was incorporated at the N-terminal portion, the binding was reduced to 10%, indicating that the N-terminus is essential for the activity. Lymphocytes and monocytes also showed specific binding sites for labeled tuftsin, but the percentage binding was lower. The differences were not significant. Addition of varying amounts of unlabeled tuftsin to the labeled tuftsin-neutrophil complex, indicated quantitative competition for the binding sites on the cells. Preincubation of the neutrophils with chicken antituftsin abolished the binding.These studies indicate that neutrophils, lymphocytes and monocytes possess receptor sites for the phagocytosis-stimulating peptide. The enzymatic cleavage and generation of tuftsin from leukokinin by the action of leukokininase on neutrophils has been suggested to be a major event in phagocytosis. The receptor sites on neutrophils for the tetrapeptide tuftsin, evidenced by our present work, provide a valuable link towards the elucidation of the mechanism of phagocytosis-stimulation. The presence of similar binding sites for tuftsin on lymphocytes and monocytes indicates a probable role for these cell populations as well, in the sequence of events during phagocytosis. Splenectomized or asplenic patients who have frequent infections may be having defective Fcreceptors on these cells or these patients may be deficient in the particular subclass of IgG and/or the specific enzyme which cleaves tuftsin from it.