The mechanisms of soluble CD83 in promoting proliferation ability of tolerant DCs and T reg cells and in sustaining immune tolerance status

Acta Universitatis Medicinalis Anhui 2023 08 v.58 1300-1305+1312     font:big middle small

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Authors:Song Qifeng; Gao Lianghui; Li Wang; Zhang Yizhong

Keywords:immunosuppressive agent;soluble CD83;tolerant DCs;T cells ;RelB;indoleamine 2,3-dioxygenase

DOI:10.19405/j.cnki.issn1000-1492.2023.08.009

〔Abstract〕 Objective To explore the molecular mechanisms of immunosuppressive activity of soluble CD83(sCD83). Methods Bone marrow-derived dendritic cells(DCs) and CD4+T cells in the spleen were isolated from bone marrow progenitor cells of 6-8-week-old C57B/6 mice. DCs and CD4+T cells were treated with 10 μl PBS(Control group) or 10 μl 10 μg/ml soluble CD83(sCD83 group), respectively. Immature DCs(imDCs) in DCs and CD4+CD25+FOXP3+T cells(Tregcells) in CD4+T cells were determined by flow cytometry. Western blot was used to determine the expression levels of indoleamine 2,3-dioxygenase(IDO) in imDCs and the expres-sion levels of phosphatase and tensin homolog(PTEN), phosphorylated-Akt serine/threonine kinase 1(p-Akt), Akt, nucleus NF-κB subunit(RelB), cytoplasm RelB and programmed cell death 1(PD-1) in Tregcells. ELISA was used to determine the level of kynurenine in DCs culture supernatant, and the levels of interleukin-10(IL-10), transforming growth factor-β(TGF-β) and IL-12 in imDCs and CD4+T cells co-culture system. Results Compared with Control group, the percentage of DCs cell counts expressing the surface markers of CD40, CD83, CD86 and major histocompatibility complex class-Ⅱ(MHC Ⅱ) in sCD83 group decreased(P<0.05), with the level of kynurenine in DCs culture supernatant increased(P<0.05). Compared with Control group, the percentage of Tregcell counts in sCD83 group increased(P<0.05), with the expression levels of PTEN and cytoplasm RelB enhanced(P<0.05), while the expression levels of p-Akt, nucleus RelB and PD-1 decreased(P<0.05). There was no significant difference in the expression level of Akt between the two groups. In the imDCs and CD4+T cells co-cultured supernatants, compared with Control group, the levels of IL-10 and TGF-β increased, and the level of IL-12 decreased in sCD83 group(P<0.05). Conclusion sCD83 can inhibit CD4+T cells nucleus RelB levels and regulate cytokines secretion so as to have an effects on cellular crosstalk of imDCs and Tregcells and promote imDCs and Tregcells proliferation.