Svensson Lena, Dahlgren Claes, Wennerås Christine
Department of Clinical Bacteriology, Sahlgrenska University Hospital, Göteborg, Sweden.
J Leukoc Biol. 2002 Oct;72(4):810-8.
Whereas prokaryotes use L- and D-isomers of amino acids in their protein synthesis, eukaryotic proteins as a rule incorporate only L-isomers. Hence, D-isomers may constitute danger signals to the innate immune system. A D-methionine-containing peptide, Trp-Lys-Tyr-Met-Val-D-Met-NH(2) (WKYMVm), has been shown to be a stronger activator of neutrophils than f-Met-Leu-Phe. The aim of this study was to compare the responsiveness of eosinophils to WKYMVm with that of neutrophils. The peptide was found to induce chemotaxis and respiratory burst in eosinophils. However, it did not mobilize granule constituents, as evidenced by a lack of eosinophil cationic protein, eosinophil peroxidase, and interleukin-5 in the supernatants of stimulated eosinophils. In contrast, WKYMVm caused the release of complement receptor 3 from secretory vesicles in neutrophils. Different members of the formyl peptide receptor family were preferentially engaged by the peptide in the two classes of granulocytes: the formyl peptide receptor itself in eosinophils and formyl peptide receptor-like 1 in neutrophils.
原核生物在蛋白质合成中使用氨基酸的L型和D型异构体，而真核生物的蛋白质通常只包含L型异构体。因此，D型异构体可能对先天免疫系统构成危险信号。一种含D-甲硫氨酸的肽，色氨酸-赖氨酸-酪氨酸-甲硫氨酸-缬氨酸-D-甲硫氨酸-NH(2)（WKYMVm），已被证明是比甲酰甲硫氨酸-亮氨酸-苯丙氨酸更强的嗜中性粒细胞激活剂。本研究的目的是比较嗜酸性粒细胞与嗜中性粒细胞对WKYMVm的反应性。发现该肽可诱导嗜酸性粒细胞的趋化性和呼吸爆发。然而，它并没有动员颗粒成分，这在受刺激的嗜酸性粒细胞上清液中缺乏嗜酸性粒细胞阳离子蛋白、嗜酸性粒细胞过氧化物酶和白细胞介素-5得到证明。相比之下，WKYMVm导致嗜中性粒细胞分泌小泡中补体受体3的释放。在这两类粒细胞中，肽优先与甲酰肽受体家族的不同成员结合：嗜酸性粒细胞中的甲酰肽受体本身和嗜中性粒细胞中的甲酰肽受体样1。
