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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. View Publication

OBJECTIVE As an inhibitor of the AhR signalling pathway,StemRegenin 1 (SR1) not only promotes the expansion of CD34+ cells but also increases CD34- cell numbers. These CD34- cells influenced the ex vivo expansion of CD34+ cells. In this work,the effects of periodically removing CD34- cells combined with SR1 addition on the ex vivo expansion and biological functions of HSCs were investigated. MATERIALS AND METHODS CD34- cells were removed periodically with SR1 addition to investigate cell subpopulations,cell expansion,biological functions,expanded cell division mode and supernatant TGF-$\beta$1 contents. RESULTS After 10-day culture,the expansion of CD34+ cells in the CD34- cell removal plus SR1 group was significantly higher than that in the control group and the SR1 group. Moreover,periodically removing CD34- cells with SR1 addition improved the biological function of expanded CD34+ cells and significantly increased the percentage of self-renewal symmetric division of CD34+ cells. In addition,the concentration of total TGF-$\beta$1 and activated TGF-$\beta$1 in the supernatant was significantly lower than those in the control group and the SR1 group. RT-qPCR results showed that the periodic removal of CD34- cells with cooperation from SR1 further reduced the expression of AhR-related genes. CONCLUSIONS Periodic removal of CD34- cells plus cooperation with SR1 improved the expansion of CD34+ cells,maintained better biological function of expanded CD34+ cells and reduced the TGF-$\beta$1 contents by downregulating AhR signalling. View Publication