Suppression Of CD8~+T Cells By Regulatory Dendritic Cells

ObjectiveTo investigate the suppression of antigen-specific CD8+T cells by DCreg induced by liver stromal cells.Method1 MACS immunomagnetic beads were used to sort OT1 CD8+T cells, DCreg, mouse bone marrow-derived mature dendritic cells.2 Flowcytometry was used to analyze the surface marker of DCreg, mDCs, imDCs, antigen-specific CD8+T activation, proliferation and secretion of cytokines in the supernatant.3 CFSE-labeled antigen-specific CD8+T cells were used to detect cell proliferation.4 RT-PCR was used to detect the secretion of cytokines and che-mokines from liver stromal cells.5 Adoptive transfusion of DCreg, mDCs and CD8+T cells to detect the inhibition of DCreg in vivo.6 Griess test kit was used to detect the NO content in culture supernatant.Results1 We established a stable liver stromal cells and the induction of DCreg.2 DCreg induced by liver stromal cells can inhibit antigen-specific CD8+T cell proliferation, but can not influence the antigen-specific CD8+T cells activation in vitro.3 DCreg cocultured with mDCs and CD8+T secreted more IL-10, but the blocking of IL-10 did not affect the antigen-specific CD8+T cell proliferation.4 The NO secreted by DCreg can inhibit antigen-specific CD8+T cell proliferation. Conclusion1 LSCs express many kinds of cytokines and chemokines.2 LSCs can make mDCs continue to proliferate and differentiate into DCreg which has the negative regulation of the immune function.3 DCreg induced by LSCs can inhibit antigen-specific CD8+T cell proliferation, but does not affect CD8+T cell activation, NO in the inhibition played a key role.4 DCreg induced by LSCs can also inhibite antigen-specific CD8+ T cell proliferation in vivoMeaningThis study shows that liver stromal microenvironment can contrib-ute to the differentiation of mDCs to DCreg, which inhibit the proli-feration of antigen-specific CD8+T cells. This inhibition mediated by DCreg was associated with NO. Our study helps to understand the role of immune tolerance in liver homeostasis. Our findings help to understand the role of the microenvironment in liver tolerance and immune homeost-asis,design stragies to eradicate chronic liver infections, treat liver ca-ncer, or prolong liver allograft survival.