Inserm U986, Diabetes & Autoimmunity Research Laboratory, Paris, France.
Blood. 2011 Aug 25;118(8):2128-37. doi: 10.1182/blood-2010-12-326231. Epub 2011 Jun 28.
Detection of human Ag-specific T cells is limited by sensitivity and blood requirements. As dendritic cells (DCs) can potently stimulate T cells, we hypothesized that their induction in PBMCs in situ could link Ag processing and presentation to Ag-specific T-cell activation. To this end, unfractionated PBMCs (fresh or frozen) or whole blood were incubated for 48 hours with protein or peptide Ag together with different DC-activating agents to rapidly and sequentially induce, pulse, and mature DCs. DC activation was therefore lined up with Ag recognition by neighboring T cells, thus telescoping the sequential steps of T-cell activation. Efficient processing of protein Ags made prior knowledge of epitopes and HLA restrictions dispensable. While reducing stimulation time, manipulation and blood requirements, in situ DC induction specifically amplified Ag-specific T-cell responses (cytokine secretion, proliferation, CD137/CD154 up-regulation, and binding of peptide-HLA multimers). IL-1β, although released by DCs, was also secreted in an Ag-specific fashion, thus providing an indirect biomarker of T-cell responses. These accelerated cocultured DC (acDC) assays offered a sensitive means with which to evaluate T-cell responses to viral and melanoma Ag vaccination, and may therefore find application for immune monitoring in viral, tumor, autoimmune, and transplantation settings.
人 Ag 特异性 T 细胞的检测受到灵敏度和血液需求的限制。由于树突状细胞 (DCs) 能够强烈刺激 T 细胞，我们假设它们在 PBMCs 原位的诱导可以将 Ag 加工和呈递与 Ag 特异性 T 细胞的激活联系起来。为此，使用未分馏的 PBMCs（新鲜或冷冻）或全血，与不同的 DC 激活剂一起孵育 48 小时，以快速、连续地诱导、脉冲和成熟 DCs。因此，DC 的激活与邻近 T 细胞对 Ag 的识别相吻合，从而缩短了 T 细胞激活的顺序步骤。高效处理预先存在的蛋白 Ag，不需要抗原表位和 HLA 限制的知识。原位 DC 诱导在减少刺激时间、操作和血液需求的同时，特异性地扩增了 Ag 特异性 T 细胞反应（细胞因子分泌、增殖、CD137/CD154 上调以及肽-HLA 多聚体的结合）。IL-1β 虽然由 DC 释放，但也以 Ag 特异性的方式分泌，因此提供了 T 细胞反应的间接生物标志物。这些加速的共培养 DC（acDC）测定提供了一种敏感的方法来评估病毒和黑色素瘤 Ag 疫苗接种后的 T 细胞反应，因此可能在病毒、肿瘤、自身免疫和移植环境中的免疫监测中得到应用。
