Stimulation of thymocyte proliferation by phosphorothioate DNA oligonucleotides.
Stimulation of thymocyte proliferation by phosphorothioate DNA oligonucleotides.
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DOI：
10.1006/cimm.2000.1635
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发表时间：
2000-04
影响因子：
4.3
通讯作者：
R. Mannon;C. Nataraj;D. Pisetsky
中科院分区：
文献类型：
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作者：
R. Mannon;C. Nataraj;D. Pisetsky
DNA是一种复杂的大分子，其免疫学特性取决于称为CpG基序或免疫刺激序列（ISS）的短序列基序。这些序列对B细胞具有促有丝分裂作用，并可刺激巨噬细胞细胞因子的产生。虽然这些序列不直接激活T细胞，但它们可以通过TCR增强刺激的效果。此外，ISS可以影响T细胞，因为巨噬细胞产生IL-12和IFN-α/β。在这些研究中，我们进一步评估了DNA对T细胞的免疫作用，测试了某些T细胞群可以直接对这种刺激做出反应的可能性。因此，我们测试了胸腺细胞的体外反应，一系列的磷酸二酯（Po）和硫代磷酸（Ps）的寡核苷酸（ODNs）的序列不同。在体外培养中，含CpG基序的硫代磷酸ODN（sODN）诱导小鼠胸腺细胞显著增殖，尽管磷酸二酯化合物缺乏活性。刺激的大小随CpG基序侧翼的序列而变化，因为dA和dT序列都增强了CpG基序的刺激能力。此外，CpG sODNs是抗CD 3介导的胸腺细胞活化的强共刺激因子，与不存在DNA的抗CD 3相比增加增殖。这种激活仅部分抑制环孢菌素A，并不依赖于钙内流。总之，这些结果表明，含有CpG基序的硫代磷酸寡核苷酸可以直接诱导胸腺细胞增殖以及增强TCR活化。因此，这些观察结果扩展了CpG DNA的作用范围，并提出了其作为免疫调节剂或佐剂的功能的其他机制。
DNA is a complex macromolecule the immunological properties of which depend on short sequence motifs called CpG motifs or immunostimulatory sequences (ISS). These sequences are mitogenic for B cells and can stimulate macrophage cytokine production. While these sequences do not directly activate T cells, they can augment effects of stimulation via the TCR. Furthermore, ISS can affect T cells because of macrophage production of IL-12 and IFN-alpha/beta. In these studies, we further evaluated the immune effects of DNA on T cells, testing the possibility that certain T cell populations can respond directly to this stimulus. We therefore tested the in vitro responses of thymocytes to a series of phosphodiester (Po) and phosphorothioate (Ps) oligonucleotides (ODNs) varying in sequence. In in vitro cultures, phosphorothioate ODNs (sODNs) containing CpG motifs induced significant proliferation of murine thymocytes, although phosphodiester compounds lacked activity. The magnitude of stimulation varied with sequences flanking the CpG motifs, as both dA and dT sequences enhanced the stimulatory capacity of the CpG motif. Furthermore, CpG sODNs were strong costimulators of anti-CD3-mediated thymocyte activation, increasing proliferation compared to anti-CD3 in the absence of DNA. This activation was only partially inhibited by cyclosporine A and was not dependent on a calcium influx. Together, these results indicate that phosphorothioate oligonucleotides containing CpG motifs can directly induce thymocyte proliferation as well as augment TCR activation. These observations thus extend the range of actions of CpG DNA and suggest additional mechanisms for its function as an immunomodulatory agent or adjuvant.