中文摘要：

目的研究配对免疫球蛋白样受体B（PIR—B）在小鼠树突细胞（Dc）上的表达及其与免疫耐受的关系。方法DC2．4为C57BL／6小鼠来源的不成熟的DC株。脂多糖（LPS）刺激48h为成熟DC（mDC）。分别以重组小鼠IL-10（rmlL-10）、重组人转化生长因子β1（rhTGFβ1）诱导DC2．4为耐受性DC（T—DC），体外化学合成PIR—B特异性RNA小干扰分子（siRNA），以Lip2000转染DC2．4（si．Dc），分别用半定量RT—PCR、Westernblot检测maiL-10、rhTGFβ1、LPS及PIR—B特异的siRNA对DC2．4上PIR—B表达的变化。以。H—TdR标记检测同种异体淋巴细胞反应（MLR），ELISA法测定MLR上清中IFN-γ的水平变化。结果RT—PCR、Westernblot结果显示DC2．4表达PIR—BmRNA及蛋白相对值为0．51±0．08和0．58±0．23；mlL-10、rhTGFβ1诱导的T—DC上PIR—B的mRNA及蛋白表达相对水平均明显升高，相对值分别为0．85±0．07和0．87±0．14；0．79±0．10和0．85±0．34（P值均〈0．05），LPS刺激的mDCPIR—BmRNA及蛋白表达则降低（0．35±0．10和0．32±0．04，P〈0．05），转染PIR—B特异性siRNA后DC2．4上PIR—B的mRNA及蛋白表达水平也明显受抑，干扰48h后分别下降了78．9％和74．2％（P〈0．05）。正常DC2．4可以刺激异基因淋巴细胞增殖；LPS—DC刺激异基因淋巴细胞增殖的能力明显增强，其反应体系中的IFN-γ水平明显升高；T—DC刺激淋巴细胞增殖的能力明显受到抑制，其反应体系中的IFN-γ水平明显下降；而转染PIR—BsiRNA后，DC刺激淋巴细胞增殖的能力得到明显恢复，其反应体系中的IFN-γ水平明显回升。结论高度表达免疫抑制性受体PIR—B是小鼠DC获得免疫耐受的共同特征及分子机制之一。

英文摘要：

Objective To investigate the expression of paired immunoglobin-like receptor B（PIR-B） on dendritic cells （DCs） and its relationship with tolerogenic DCs （T-DCs） in mouse. Methods DC2.4 cells, an immature dendritic cell line derived from C57BL/6 mouse, were stimulated by lipopolysaccharide （LPS） for48 h to induce the mature dendritic cells（mDC） and cultured respectively with the recombined mouse interleukin-10（rmlL-10） or recombined human transforming growth factorβ1 （rhTGF-β1） to develop the tolerogenic dendritic cells （T-DC）. Special small interference RNA （siRNA） molecular of PIR-B was chemically synthesized and transfected into DC2.4 cells （si-DC） by lip2000. The expression of PIR-B on DC2.4 cells was measured by semi-quantitative reverse transcription polymerase chain reaction （RT-PCR） and Western blot. The allogeneic lymphocyte proliferative capacity of DCs was measured by mixed lymphocyte reaction （MLR） using SH-thymidine incorporation test. The concentration of IFN-γ in supernatants of MLR was analyzed by ELISA. Results Semi-quantitative RT-PCR and Western blot showed that PIR-B mRNA and protein were expressed on DC2.4 cells. RmIL-10 and rhTGF-β1 induced the higher PIR-B mRNA and protein level on T-DCs（ Relative values were 0. 51 ± 0. 08 and 0. 58 ± 0. 23 ;0.85 ± 0. 07 and 0. 87 ± 0. 14 ; 0. 79 ± 0. 10 and 0. 85 ± 0. 34, respectively）（ P 〈 0. 05 ）. LPS down-regulated the PIR-B expression on mDC （0.35 ± 0.10 and 0.32 ± 0.04 ） （P 〈 0.05 ）. The PIR-B mRNA and protein expression were inhibited by siRNA transfection （ decreased by 78.9% and 74.2% respectively after 48 h interference） （ P 〈 0.05 ）. DC2.4 cells stimulated the proliferation of BALB/c mouse allogenetic spleen cell. The mDC enhanced alloreactivity in MLR and the IFN-γ secretion in supernatants. The T-DCs alleviated the allogenetic spleen cell proliferation（ P 〈0.05 ） and IFN-γsecretion in MLR （P 〈 0.05 ）. Silence of the PIR-B expression（si-DC）