B7-H1对HIV/AIDS患者mDCs活化异源性T淋巴细胞的功能影响

摘要

目的 观察HIV感染患者mDCs表面B7-H1表达对T淋巴细胞免疫功能的影响,探讨HIV/AIDS患者细胞免疫功能低下的分子机制.方法 将患者和健康者来源的mDCs与异源健康者的CD3+T细胞按不同比例混合后培养,采用[3H]-TdR掺入法检测T细胞的增殖,并采用流式微球阵列分析(cytometric bead assay,CBA)检测细胞培养上清中细胞因子浓度,细胞染色检测T细胞分泌IFN-γ和IL-4水平,并观察用B7-H1单克隆抗体5H1阻断B7-H1信号后的效果.结果 比较患者来源、健康者来源的mDCs其刺激异源性CD3+T细胞增殖能力,结果显示患者来源mDCs其刺激能力明显降低；加入B7-H1单克隆抗体后,能够恢复患者mDCs对T细胞的刺激能力.CBA结果显示,阻断B7-H1抑制信号细胞培养上清中1型细胞因子IFN-γ、IL-12、TNF-α、TNF-β和IL-1β的浓度明显升高,而2型细胞因子IL-4和IL-10的浓度则明显降低,且流式细胞内因子染色方法结果显示,阻断B7-H1信号能够明显提高T细胞1型细胞因子IFN-γ的产生,而产生2型细胞因子IL-4的CD3+T则减少.结论 HIV/AIDS患者T细胞功能降低可能关键由mDCs上B7-H1表达频率的升高引起,阻断B7-H1负向调控信号,T细胞的免疫功能有所恢复,可能是艾滋病的一个潜在的免疫治疗方法.%Objective The present study aims at elucidating the molecular mechanism of cellular immune functional defects in HIV infection.This study is designed to investigate on the effect of mDCs mediated by B7-H1 signal on immune function of T cells in patients with HIV infection.Methods We cultured mDCs from HIV patients and healthy controls respectively with CD3 + T ceils from a third healthy individual at different ratio of mDCs and T cells.T-cell proliferation was assessed by the incorporation of[3H] thymidine.Meanwhile,ten cytokines such as IFN-γ,IL-10,IL-12 and IL-4 et al in the co-cultured supernatants were detected by Multiplex cytometric bead assay (CBA),and intracellular IFN-γ and IL-4 were detected by intracellular cytokine staining.Results The results showed that mDCs from HIV patients had a significantly reduced capacity to stimulate allogeneic CD3 + T cell proliferation at all ratios tested compared with healthy controls,while blockade of B7-H1 pathway with 5-H 1 (anti-B7-H1) could significantly reverse the capacity.Blockade of B7-H1 signal,mDCs of HIV patients showed a significantly increased capacity to stimulate allogeneic CD3 + T cells to produce type 1 cytokines such as IFN-γ,IL-12,TNF-α,TNF-β and IL-1 β at the 1∶20 ratio and decreased type 2 cytokines such as IL-4 and IL-10 production compared with a group treated with control Ig.This result was confirmed by intracellular cytokine staining which showed increased mDCs stimulating IFN-γ + CD3 + T cells and declined IL-4 + CD3 + T cells by blocking B7-H1 signal.Conclusion These data suggest that B7-H1 up-regulation on mDCs may be responsible for the defective T-cell immune function in HIV infection.Blockade of B7-H1 in vitro strongly enhances mDC-mediated allostimulatory capacity of T cells proliferation and type 1 cytokines production.Our findings begin to shed light on the notion that B7-H1 blockade represents a potential therapeutic approach for this disease.