Chabannes B, Hosni R, Molière P, Croset M, Pacheco Y, Perrin-Fayolle M, Lagarde M
INSERM U.205, Institut National des Sciences Appliquées, Villeurbanne, France.
Biochim Biophys Acta. 1991 Jun 7;1093(1):47-54. doi: 10.1016/0167-4889(91)90137-m.
Peripheral blood neutrophils from patients with allergic rhinitis and from normal subjects were incubated for 5 min at 37 degrees C with 0.15 microM calcium ionophore A23187 in the absence or presence of exogenous arachidonic acid (2.5 to 10 microM). In neutrophils from allergic patients, the leukotriene B4 (LTB4) level was significantly increased by exogenous arachidonic acid in a concentration-dependent manner (16.2 +/- 4.2 and 38.1 +/- 6.8 pmol/5 min per 2 X 10(6) cells in the absence and presence of 10 microM arachidonic acid, respectively; P less than 0.005; n = 8). The LTB4 level in neutrophils from healthy subjects was only 0.97 +/- 0.17 pmol/5 min per 2 x 10(6) cells (n = 5) and was not enhanced by exogenous arachidonate. When cells from allergic patients were challenged in the presence of exogenous [1-14C]arachidonic acid, released LTB4 was radiolabeled and the incorporated radioactivity increased with the labeled arachidonate concentration. Labeled LTB4 was never detectable after incubating neutrophils from normal donors with exogenous labeled arachidonate. When neutrophils were incubated with [1-14C]arachidonate for 1 h, the different lipid pools of the two cell populations were labeled but both types of neutrophils produced unlabeled LTB4 in response to ionophore stimulation. The hydrolysis of choline and ethanolamine phospholipids into diacyl-, alkenylacyl- and alkylacyl-species revealed that solely the alkylacyl-subclass of phosphatidylcholine was unlabeled. We conclude (i) that neutrophils from allergic patients stimulated by low ionophore concentration produce more LTB4 than neutrophils from healthy subjects and incorporate exogenous arachidonate, (ii) that endogenous arachidonate converted to LTB4 by the 5-lipoxygenase pathway may provide only from 1-O-alkyl-2-arachidonoyl-glycero-3-phosphocholine.
将过敏性鼻炎患者和正常受试者的外周血中性粒细胞在37℃下与0.15微摩尔钙离子载体A23187孵育5分钟，同时分别加入或不加入外源性花生四烯酸（2.5至10微摩尔）。在过敏性患者的中性粒细胞中，外源性花生四烯酸以浓度依赖的方式显著增加白三烯B4（LTB4）水平（在不存在和存在10微摩尔花生四烯酸的情况下，每2×10⁶个细胞分别为16.2±4.2和38.1±6.8皮摩尔/5分钟；P＜0.005；n = 8）。健康受试者中性粒细胞中的LTB4水平仅为每2×10⁶个细胞0.97±0.17皮摩尔/5分钟（n = 5），且外源性花生四烯酸不会使其升高。当过敏性患者的细胞在外源性[1-¹⁴C]花生四烯酸存在下受到刺激时，释放的LTB4被放射性标记，且掺入的放射性随着标记花生四烯酸浓度的增加而增加。用外源性标记花生四烯酸孵育正常供体的中性粒细胞后，从未检测到标记的LTB4。当中性粒细胞与[1-¹⁴C]花生四烯酸孵育1小时时，两个细胞群体的不同脂质池都被标记，但两种类型的中性粒细胞在受到离子载体刺激时都会产生未标记的LTB4。胆碱和乙醇胺磷脂水解为二酰基、烯基酰基和烷基酰基种类，结果显示仅磷脂酰胆碱的烷基酰基亚类未被标记。我们得出结论：（i）低浓度离子载体刺激下，过敏性患者的中性粒细胞比健康受试者的中性粒细胞产生更多的LTB4，并掺入外源性花生四烯酸；（ii）通过5-脂氧合酶途径转化为LTB4的内源性花生四烯酸可能仅来自1-O-烷基-2-花生四烯酰基甘油-3-磷酸胆碱。
