Cole E H, Neil G, Myers-Mason N, Fung L S, Levy G A
Department of Medicine, University of Toronto, Canada.
J Autoimmun. 1995 Feb;8(1):47-59. doi: 10.1006/jaut.1995.0004.
Plasma procoagulant activity inducing factor (PIF) is a spontaneously occurring, potent inducer of macrophage procoagulant activity (PCA) in the male BXSB murine model of systemic lupus erythematosus. The physical characteristics of PCA induction by PIF, aggregated mouse IgG, and lipopolysaccharide (LPS) were compared. Both aggregated IgG and PIF-induced PCA were heat, acid and alkali sensitive. In contrast, LPS-induced PCA was heat resistant and only partially acid and alkali sensitive. Plasma containing PIF was fractionated on Sephacryl S-300. The PIF activity localized to the first protein peak, molecular weight 400,000 to 900,000 daltons. Analysis of peak 1 by an enzyme-linked immunosorbent assay showed the presence of IgM, IgA and IgG. This was confirmed by Western blot analysis using 125I-labelled goat anti-mouse IgM, IgA and IgG probes. The concentration of PIF increased with Sephacryl S-300 chromatography and was reduced by removal of IgG, but not IgA or IgM by affinity chromatography. Peak 1 did not contain DNA as revealed by ethidium bromide staining. Thus, IgG from the plasma of BXSB mice, a strain which develops lupus nephritis, stimulates macrophages to express PCA, accounting for PCA induction in the BXSB model of murine lupus.
血浆促凝活性诱导因子（PIF）是在雄性BXSB系统性红斑狼疮小鼠模型中自发产生的巨噬细胞促凝活性（PCA）的强效诱导剂。比较了PIF、聚集的小鼠IgG和脂多糖（LPS）诱导PCA的物理特性。聚集的IgG和PIF诱导的PCA对热、酸和碱敏感。相比之下，LPS诱导的PCA耐热，仅对酸和碱部分敏感。含有PIF的血浆在Sephacryl S-300上进行分级分离。PIF活性定位于第一个蛋白峰，分子量为400,000至900,000道尔顿。通过酶联免疫吸附测定对峰1进行分析，结果显示存在IgM、IgA和IgG。使用125I标记的山羊抗小鼠IgM、IgA和IgG探针进行的蛋白质印迹分析证实了这一点。PIF的浓度随着Sephacryl S-300色谱法而增加，通过亲和色谱法去除IgG后浓度降低，但去除IgA或IgM后浓度未降低。溴化乙锭染色显示峰1中不含有DNA。因此，来自发生狼疮性肾炎的BXSB小鼠血浆中的IgG刺激巨噬细胞表达PCA，这解释了小鼠狼疮的BXSB模型中PCA的诱导。
