Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Cytokine. 2012 Apr;58(1):20-6. doi: 10.1016/j.cyto.2011.12.017. Epub 2012 Jan 15.
We have previously described an alternatively spliced isoform of IL-4 mRNA that omits exon 2 and is termed IL-4δ2. However, the natural production of IL-4δ2 protein and its association with disease have not been previously assessed due to unavailability of an antibody that interacts with IL-4δ2 without cross-reactivity with full length IL-4. We used a unique monoclonal antibody (mAb) that reacts with IL-4δ2, but not with IL-4, and observed that IL-4δ2 is naturally produced by T cells from patients with asthma, but not from healthy controls. The kinetics of IL-4δ2 and IL-4 production by phorbol myristate acetate (PMA)/ionomycin-activated cells differed, with IL-4δ2 increasing at 48-72h and IL-4 peaking at 24h. The steady-state levels of IL-4δ2 mRNA varied significantly among the donors and were discordant with the corresponding protein levels, suggesting post-transcriptional regulation of protein production. Polarized Th1 or Th2 lymphocytes were not a major source of IL-4δ2. Stimulation of cultured T lymphocytes with IL-4δ2 caused elevated production of IFN-γ, IL-10, IL-6, MCP-1, and TNF-α, with notable differences between patients and controls in the production of IFN-γ, IL-10, and IL-6. Thus, IL-4δ2 is natively produced not only as mRNA but also as a protein by cells other than Th1 or Th2. It is regulated post-transcriptionally, is associated with allergic asthma, and regulates production of other cytokines by primary T lymphocytes. Alternatively spliced interleukin-4 may be a new biomarker, a pathophysiological player, and possibly a molecular target for future therapies in asthma.
我们之前描述了一种 IL-4 mRNA 的选择性剪接异构体，它缺失外显子 2 并被称为 IL-4δ2。然而，由于缺乏与 IL-4δ2 相互作用而不与全长 IL-4 发生交叉反应的抗体，IL-4δ2 蛋白的自然产生及其与疾病的关联以前尚未得到评估。我们使用了一种独特的单克隆抗体 (mAb)，该抗体与 IL-4δ2 反应，但不与 IL-4 反应，并观察到 IL-4δ2 是由哮喘患者的 T 细胞自然产生的，但不是由健康对照者产生的。佛波醇肉豆蔻酸酯 (PMA)/离子霉素激活细胞产生的 IL-4δ2 和 IL-4 的动力学不同，IL-4δ2 在 48-72 小时增加，而 IL-4 在 24 小时达到峰值。IL-4δ2 mRNA 的稳态水平在供体之间差异显著，与相应的蛋白水平不一致，提示蛋白产生的转录后调节。极化的 Th1 或 Th2 淋巴细胞不是 IL-4δ2 的主要来源。用 IL-4δ2 刺激培养的 T 淋巴细胞会导致 IFN-γ、IL-10、IL-6、MCP-1 和 TNF-α 的产生增加，患者和对照者在 IFN-γ、IL-10 和 IL-6 的产生方面存在显著差异。因此，IL-4δ2 不仅以 mRNA 形式，而且以 Th1 或 Th2 以外的细胞表达的蛋白形式天然产生。它受到转录后调节，与过敏性哮喘有关，并调节原代 T 淋巴细胞产生其他细胞因子。选择性剪接的白细胞介素 4 可能是一种新的生物标志物、病理生理因子，并且可能是哮喘未来治疗的分子靶点。
