非结核分枝杆菌感染患者抗 IFN-γ 自身抗体的功能中和作用。

Functional neutralization of anti-IFN-γ autoantibody in patients with nontuberculous mycobacteria infection.

机构信息

Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.

Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.

出版信息

Sci Rep. 2019 Apr 5;9(1):5682. doi: 10.1038/s41598-019-41952-1.

Interferon (IFN)-γ is crucial for normal immune surveillance and exhibits immunomodulatory, antimicrobial, and anticancer activity. Patients with nontuberculous mycobacteria (NTM) infection commonly express high levels of anti-IFN-γ autoantibodies (autoAbs) and suffer from recurrent infections due to adult-onset immunodeficiency with defects in IFN-γ immune surveillance. In this study, we developed the methods for determination of anti-IFN-γ autoAbs and then characterized their neutralizing activity in patients with NTM infection. A modified sandwich ELISA-based colorimetric assay followed by immunoblot analysis detected the presence of autoAbs in three out of five serum samples. Serum levels of IFN-γ were decreased. Synthetic peptide binding assay showed variable patterns of epitope recognition in patients positive for anti-IFN-γ autoAbs. Functional tests confirmed that patient serum blocked IFN-γ-activated STAT1 activation and IRF1 transactivation. Furthermore, IFN-γ-regulated inflammation, chemokine production and cytokine production were also blocked. These results provide potentially useful methods to assay anti-IFN-γ autoAbs and to characterize the effects of neutralizing autoAbs on IFN-γ signaling and bioactivity.

干扰素 (IFN)-γ 对于正常的免疫监视至关重要，具有免疫调节、抗微生物和抗癌活性。分枝杆菌（NTM）感染患者通常表达高水平的抗 IFN-γ 自身抗体（autoAbs），并且由于 IFN-γ 免疫监视缺陷导致成人获得性免疫缺陷而遭受反复感染。在这项研究中，我们开发了检测抗 IFN-γ 自身抗体的方法，并随后表征了它们在 NTM 感染患者中的中和活性。改良的夹心 ELISA 比色法结合免疫印迹分析检测到五份血清样本中的三份存在自身抗体。血清 IFN-γ 水平降低。合成肽结合试验显示出患者中针对 IFN-γ 自身抗体的表位识别的可变模式。功能测试证实患者血清阻断了 IFN-γ 激活的 STAT1 激活和 IRF1 反式激活。此外，IFN-γ 调节的炎症、趋化因子产生和细胞因子产生也被阻断。这些结果提供了有用的方法来检测抗 IFN-γ 自身抗体，并表征中和自身抗体对 IFN-γ 信号传导和生物活性的影响。