Institute of Molecular Biology and Pathology, National Research Council (CNR), Rome, Italy.
Department of Molecular Medicine, University of Rome "Sapienza", Rome, Italy.
Scand J Immunol. 2019 Feb;89(2):e12735. doi: 10.1111/sji.12735. Epub 2019 Jan 15.
Although clonal expansion is a hallmark of adaptive immunity, the location(s) where antigen-responding T cells enter cell cycle and complete it have been poorly explored. This lack of knowledge stems partially from the limited experimental approaches available. By using Ki67 plus DNA staining and a novel strategy for flow cytometry analysis, we distinguished antigen-specific CD8 T cells in G , in G and in S-G /M phases of cell cycle after intramuscular vaccination of BALB/c mice with antigen-expressing viral vectors. Antigen-specific cells in S-G /M were present at early times after vaccination in lymph nodes (LNs), spleen and, surprisingly, also in the blood, which is an unexpected site for cycling of normal non-leukaemic cells. Most proliferating cells had high scatter profile and were undetected by current criteria of analysis, which under-estimated up to 6 times antigen-specific cell frequency in LNs. Our discovery of cycling antigen-specific CD8 T cells in the blood opens promising translational perspectives.
虽然克隆扩增是适应性免疫的一个标志，但抗原反应性 T 细胞进入细胞周期并完成细胞周期的位置（部位）尚未得到很好的探索。这种知识的缺乏部分源于可用的实验方法有限。通过使用 Ki67 加 DNA 染色和一种新的流式细胞术分析策略，我们在 BALB/c 小鼠肌肉内接种表达抗原的病毒载体后，区分了细胞周期 G 期、G 和 S-G / M 期的抗原特异性 CD8 T 细胞。在接种后早期，淋巴结（LN）、脾脏中存在抗原特异性细胞 S-G / M，令人惊讶的是，血液中也存在抗原特异性细胞 S-G / M，这是正常非白血病细胞循环的意外部位。大多数增殖细胞具有高散射谱，并且无法通过当前的分析标准检测到，这使 LN 中抗原特异性细胞的频率低估了多达 6 倍。我们在血液中发现了循环抗原特异性 CD8 T 细胞，这为转化研究开辟了有希望的前景。
