Advanced Eye Centre, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
Department of Microbiology and Immunology and the Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
Scand J Immunol. 2022 Nov;96(5). doi: 10.1111/sji.13214. Epub 2022 Aug 25.
CpG Oligodeoxynucleotides (ODNs) are established TLR9 ligands; however, their functional responses in CD4+ T cells are believed to be independent of TLR9 and MyD88. We studied ligand-receptor interactions of ODN 2216 and TLR9 in human CD4+ T cells and assessed their consequences in terms of TLR9 signalling and cell phenotype. We demonstrated that the uptake of ODN 2216, a synthetic TLR9 agonist, is controlled by TLR9 signalling molecules and results in an increase in the expression of TLR9 signalling molecules, regulated via a feedback mechanism. Next, the uptake of ODN 2216 resulted in TLR9 signalling dependent but MyD88 independent increase in expression of TGF-β. Finally, ODN 2216 treated CD4+ T cells showed an anti-inflammatory phenotype that was similar to Th3 type of regulatory T cells. These Th3-like cells were able to suppress the proliferation of untreated CD4+ T cells. Collectively, our results demonstrate a direct and interdependent relationship between ODN 2216 uptake and TLR9 signalling in CD4+ T cells. Our findings thus pave the way for future research to explore direct modulation of adaptive immune cells, using innate immune ligands, to subvert exaggerated inflammatory responses.
CpG 寡脱氧核苷酸(ODNs)是已确立的 TLR9 配体;然而,人们认为它们在 CD4+T 细胞中的功能反应独立于 TLR9 和 MyD88。我们研究了 ODN 2216 与 TLR9 在人 CD4+T 细胞中的配体-受体相互作用,并评估了它们在 TLR9 信号转导和细胞表型方面的后果。我们证明,TLR9 信号分子控制着合成 TLR9 激动剂 ODN 2216 的摄取,导致 TLR9 信号分子的表达增加,这是通过反馈机制调节的。接下来,ODN 2216 的摄取导致 TLR9 信号依赖性但 MyD88 非依赖性 TGF-β表达增加。最后,ODN 2216 处理的 CD4+T 细胞表现出抗炎表型,类似于 Th3 型调节性 T 细胞。这些 Th3 样细胞能够抑制未处理的 CD4+T 细胞的增殖。总之,我们的研究结果表明 ODN 2216 摄取与 CD4+T 细胞中的 TLR9 信号之间存在直接和相互依赖的关系。我们的研究结果为未来的研究铺平了道路,这些研究旨在探索使用先天免疫配体直接调节适应性免疫细胞,以颠覆过度的炎症反应。