B 淋巴细胞刺激因子/增殖诱导配体异三聚体在自身免疫性疾病患者的血清中升高，并可被阿巴西普和 B 细胞成熟抗原-免疫球蛋白中和。

B-lymphocyte stimulator/a proliferation-inducing ligand heterotrimers are elevated in the sera of patients with autoimmune disease and are neutralized by atacicept and B-cell maturation antigen-immunoglobulin.

机构信息

Preclinical Research and Development, ZymoGenetics, Inc, 1201 Eastlake Ave East, Seattle, WA 98102, USA.

出版信息

Arthritis Res Ther. 2010;12(2):R48. doi: 10.1186/ar2959. Epub 2010 Mar 19.

DOI:10.1186/ar2959

PMID:20302641

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC2888197/

Abstract

INTRODUCTION

B-lymphocyte stimulator (BLyS) and a proliferation-inducing ligand (APRIL) are members of the tumor necrosis factor (TNF) family that regulate B-cell maturation, survival, and function. They are overexpressed in a variety of autoimmune diseases and reportedly exist in vivo not only as homotrimers, but also as BLyS/APRIL heterotrimers.

METHODS

A proprietary N-terminal trimerization domain was used to produce recombinant BLyS/APRIL heterotrimers. Heterotrimer biologic activity was compared with that of BLyS and APRIL in a 4-hour signaling assay by using transmembrane activator and CAML interactor (TACI)-transfected Jurkat cells and in a 4-day primary human B-cell proliferation assay. A bead-based immunoassay was developed to quantify native heterotrimers in human sera from healthy donors (n = 89) and patients with systemic lupus erythematosus (SLE; n = 89) or rheumatoid arthritis (RA; n = 30). Heterotrimer levels were compared with BLyS and APRIL homotrimer levels in a subset of these samples.

RESULTS

The recombinant heterotrimers consisted mostly of one BLyS and two APRIL molecules. Heterotrimer signaling did not show any significant difference compared with APRIL in the TACI-Jurkat assay. Heterotrimers were less-potent inducers of B-cell proliferation than were homotrimeric BLyS or APRIL (EC(50), nMol/L: BLyS, 0.02; APRIL, 0.17; heterotrimers, 4.06). The soluble receptor fusion proteins atacicept and B-cell maturation antigen (BCMA)-immunoglobulin (Ig) neutralized the activity of BLyS, APRIL, and heterotrimers in both cellular assays, whereas B-cell activating factor belonging to the TNF family receptor (BAFF-R)-Ig neutralized only the activity of BLyS. In human sera, significantly more patients with SLE had detectable BLyS (67% versus 18%; P < 0.0001), APRIL (38% versus 3%; P < 0.0002), and heterotrimer (27% versus 8%; P = 0.0013) levels compared with healthy donors. Significantly more patients with RA had detectable APRIL, but not BLyS or heterotrimer, levels compared with healthy donors (83% versus 3%; P < 0.0001). Heterotrimer levels weakly correlated with BLyS, but not APRIL, levels.

CONCLUSIONS

Recombinant BLyS/APRIL heterotrimers have biologic activity and are inhibited by atacicept and BCMA-Ig, but not by BAFF-R-Ig. A novel immunoassay demonstrated that native BLyS/APRIL heterotrimers, as well as BLyS and APRIL homotrimers, are elevated in patients with autoimmune diseases.

摘要

简介

B 淋巴细胞刺激因子（BLyS）和增殖诱导配体（APRIL）是肿瘤坏死因子（TNF）家族的成员，可调节 B 细胞的成熟、存活和功能。它们在多种自身免疫性疾病中过度表达，据报道，它们不仅以同源三聚体的形式存在于体内，而且还以 BLyS/APRIL 异源三聚体的形式存在。

方法

使用专有的 N 端三聚化结构域来产生重组 BLyS/APRIL 异源三聚体。在通过转染跨膜激活剂和钙调神经磷酸酶相互作用分子（TACI）的 Jurkat 细胞的 4 小时信号转导测定中和在体外原代人 B 细胞增殖测定中，比较异源三聚体的生物活性与 BLyS 和 APRIL 的生物活性。开发了一种基于珠子的免疫测定法来定量来自健康供体（n = 89）和系统性红斑狼疮（SLE；n = 89）或类风湿关节炎（RA；n = 30）患者的人血清中的天然异源三聚体。在这些样本的一部分中，比较了异源三聚体水平与 BLyS 和 APRIL 同源三聚体水平。

结果

重组异源三聚体主要由一个 BLyS 和两个 APRIL 分子组成。与 TACI-Jurkat 测定中的 APRIL 相比，异源三聚体信号没有显示出任何显著差异。与同源三聚体 BLyS 或 APRIL 相比，异源三聚体诱导 B 细胞增殖的能力较弱（EC（50），nMol/L：BLyS，0.02；APRIL，0.17；异源三聚体，4.06）。可溶性受体融合蛋白 atacicept 和 B 细胞成熟抗原（BCMA）-Ig 中和了细胞测定中 BLyS、APRIL 和异源三聚体的活性，而 B 细胞激活因子属于 TNF 家族受体（BAFF-R）-Ig 仅中和了 BLyS 的活性。在人血清中，与健康供体相比，SLE 患者中明显更多的患者可检测到 BLyS（67%与 18%；P < 0.0001）、APRIL（38%与 3%；P < 0.0002）和异源三聚体（27%与 8%；P = 0.0013）水平。与健康供体相比，RA 患者中明显更多的患者可检测到 APRIL，但不能检测到 BLyS 或异源三聚体（83%与 3%；P < 0.0001）。异源三聚体水平与 BLyS 呈弱相关，但与 APRIL 水平不相关。