Lee M J, Silver R K, O'Connell P D, Caplan M S
Division of Maternal-Fetal Medicine, Northwestern University Medical School Evanston Hospital, Illinois 60201.
Prostaglandins. 1994 Mar;47(3):221-31. doi: 10.1016/0090-6980(94)90062-0.
Enhanced endothelial cell 1-acyl platelet-activating factor (1-acylPAF) synthesis has been identified as a consequence of anticardiolipin-antibody-positive serum exposure. While this observation suggests that PAF analogues may play a role in antibody-mediated vasculopathy, it has not been determined whether the antibodies themselves are directly responsible for stimulating 1-acylPAF production. The objective of the current study was to determine whether extracted immunoglobulins or non-immunoglobulin serum constituents are responsible for the increased endothelial cell 1-acylPAF production previously observed. Sera from six ACA-positive, non-pregnant women were precipitated with ammonium sulfate and dialyzed to extract their respective immunoglobulin fractions. IgG, A and M concentrations were measured by nephelometry before and after precipitation and enzyme immunoassay was used to quantify anticardiolipin antibody activity in both whole serum and immunoglobulin suspensions. Paired endothelial cell monolayers were incubated separately with 20% whole serum and the corresponding immunoglobulin fraction from each patient source. After ionophore A23187 stimulation, intracellular PAF production was measured by lipid extraction and radiolabeling. RadylPAF species were distinguished by zonal thin-layer chromatography. Mean radylPAF synthesis was compared between experimental conditions by paired T-test. Significantly more endothelial cell radylPAF synthesis was observed subsequent to whole serum exposure as compared to incubation with the corresponding immunoglobulin fractions (19154 +/- 1916 vs 11785 +/- 1778; dpm, mean +/- SE; p = 0.007); the majority of recovered radylPAF was the sn-1-acyl derivative. Serum samples recovered after immunoglobulin extraction, retained similar stimulatory activity for radylPAF (23045 +/- 4175 dpm) in comparison to intact whole serum (19635 +/- 1266 dpm; p = 0.25). These findings suggest that in ACA-positive serum, non-immunoglobulin constituents provide greater stimulation of 1-acylPAF synthesis than the immunoglobulins themselves.
抗心磷脂抗体阳性血清暴露会导致内皮细胞1-酰基血小板活化因子（1-酰基PAF）合成增强。虽然这一观察结果表明PAF类似物可能在抗体介导的血管病变中起作用，但尚未确定抗体本身是否直接导致1-酰基PAF生成增加。本研究的目的是确定先前观察到的内皮细胞1-酰基PAF生成增加是由提取的免疫球蛋白还是非免疫球蛋白血清成分所致。对6名抗心磷脂抗体阳性的非妊娠女性的血清进行硫酸铵沉淀和透析，以提取各自的免疫球蛋白组分。沉淀前后通过散射比浊法测定IgG、A和M浓度，并采用酶免疫测定法定量全血清和免疫球蛋白悬浮液中的抗心磷脂抗体活性。将成对的内皮细胞单层分别与20%全血清和来自每个患者来源的相应免疫球蛋白组分一起孵育。在用离子载体A23187刺激后，通过脂质提取和放射性标记测量细胞内PAF生成。通过区带薄层色谱法区分放射性PAF种类。通过配对t检验比较实验条件下的平均放射性PAF合成。与相应免疫球蛋白组分孵育相比，全血清暴露后观察到的内皮细胞放射性PAF合成显著更多（19154±1916对11785±1778；dpm，平均值±标准误；p = 0.007）；回收的放射性PAF大部分是sn-1-酰基衍生物。与完整全血清（19635±1266 dpm；p = 0.25）相比，免疫球蛋白提取后回收的血清样品对放射性PAF仍保留类似的刺激活性（23045±4175 dpm）。这些发现表明，在抗心磷脂抗体阳性血清中，非免疫球蛋白成分比免疫球蛋白本身对1-酰基PAF合成的刺激作用更大。
