Tadayon Sina, Dunkel Johannes, Takeda Akira, Eichin Dominik, Virtakoivu Reetta, Elima Kati, Jalkanen Sirpa, Hollmén Maija
MediCity Research Laboratory, University of Turku, Turku, Finland.
Turku Graduate School of Molecular Medicine, University of Turku, Turku, Finland.
Front Immunol. 2021 Mar 4;12:602122. doi: 10.3389/fimmu.2021.602122. eCollection 2021.
Clever-1 also known as Stabilin-1 and FEEL-1 is a scavenger molecule expressed on a subpopulation of anti-inflammatory macrophages and lymphatic endothelial cells (LECs). However, its role in regulating dendritic cell (DC) trafficking and subsequent effects on immunity have remained unexplored. In this study, we demonstrate that DC trafficking from the skin into the draining lymph nodes is compromised in the absence of Clever-1. By adoptive transfer approaches we further show that the poor trafficking is due to the impaired entrance of DCs into afferent lymphatics. Despite this, injections of ovalbumin-loaded DCs into the footpads induced a stronger proliferative response of OT II T cells in the draining lymph nodes. This could be explained by the increased MHC II expression on DCs and a less tolerogenic phenotype of LECs in lymph nodes of Clever-1 knockout mice. Thus, although fewer DCs reach the nodes, they are more active in creating antigen-specific immune responses. This suggests that the DCs migrating to the draining lymph node within Clever-1 positive lymphatics experience immunosuppressive interactions with LECs. In conclusion, besides being a trafficking molecule on lymphatic vasculature Clever-1 is immunosuppressive towards migrating DCs and thus, regulates the magnitude of immune responses created by incoming DCs in the draining lymph nodes.
Clever-1也被称为Stabilin-1和FEEL-1,是一种在抗炎巨噬细胞和淋巴管内皮细胞(LEC)亚群上表达的清道夫分子。然而,其在调节树突状细胞(DC)迁移以及对免疫的后续影响方面的作用仍未得到探索。在本研究中,我们证明在缺乏Clever-1的情况下,DC从皮肤向引流淋巴结的迁移受到损害。通过过继转移方法,我们进一步表明迁移不佳是由于DC进入输入淋巴管受损所致。尽管如此,将负载卵清蛋白的DC注射到脚垫中会在引流淋巴结中诱导OT II T细胞产生更强的增殖反应。这可以通过Clever-1基因敲除小鼠淋巴结中DC上MHC II表达增加以及LEC的致耐受性降低来解释。因此,尽管到达淋巴结的DC较少,但它们在产生抗原特异性免疫反应方面更活跃。这表明在Clever-1阳性淋巴管内迁移到引流淋巴结的DC与LEC发生免疫抑制相互作用。总之,除了作为淋巴管系统上的迁移分子外,Clever-1对迁移的DC具有免疫抑制作用,因此调节引流淋巴结中传入DC产生的免疫反应强度。