Granucci Francesca, Feau Sonia, Angeli Véronique, Trottein François, Ricciardi-Castagnoli Paola
Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy.
J Immunol. 2003 May 15;170(10):5075-81. doi: 10.4049/jimmunol.170.10.5075.
Dendritic cells (DCs) are professional APCs able to initiate innate and adaptive immune responses against invading pathogens. Different properties such as the efficient Ag processing machinery, the high levels of expression of costimulatory molecules and peptide-MHC complexes, and the production of cytokines contribute in making DCs potent stimulators of naive T cell responses. Recently we have observed that DCs are able to produce IL-2 following bacterial stimulation, and we have demonstrated that this particular cytokine is a key molecule conferring to early bacterial activated DCs unique T cell priming capacity. In the present study we show that many different microbial stimuli, but not inflammatory cytokines, are able to stimulate DCs to produce IL-2, indicating that DCs can distinguish a cytokine-mediated inflammatory process from the actual presence of an infection. The capacity to produce IL-2 following a microbial stimuli encounter is a feature shared by diverse DC subtypes in vivo, such as CD8 alpha(+) and CD8 alpha(-) splenic DCs and epidermal Langerhans cells. When early activated DCs interact with T cells, IL-2 produced by DCs is enriched at the site of cell-cell contact, confirming the importance of DCs-derived IL-2 in T cell activation.
树突状细胞（DCs）是专职抗原呈递细胞，能够启动针对入侵病原体的先天性和适应性免疫反应。不同的特性，如高效的抗原加工机制、共刺激分子和肽-MHC复合物的高表达水平以及细胞因子的产生，都有助于使DCs成为幼稚T细胞反应的有效刺激物。最近我们观察到，DCs在细菌刺激后能够产生白细胞介素-2（IL-2），并且我们已经证明这种特定的细胞因子是赋予早期细菌激活的DCs独特T细胞启动能力的关键分子。在本研究中，我们表明许多不同的微生物刺激物，而不是炎性细胞因子，能够刺激DCs产生IL-2，这表明DCs能够将细胞因子介导的炎症过程与感染的实际存在区分开来。在遇到微生物刺激后产生IL-2的能力是体内多种DC亚型共有的特征，如CD8α(+)和CD8α(-)脾DCs以及表皮朗格汉斯细胞。当早期激活的DCs与T细胞相互作用时，DCs产生的IL-2在细胞-细胞接触部位富集，证实了DCs来源的IL-2在T细胞激活中的重要性。
