IL-7Rα(抗体对Ⅱ型胶原诱导性关节炎小鼠T细胞作用机制研究

Mechanism for effect of IL-7Rα antibody on T cells from collagenⅡ-induced arthritis mice

本研究探讨应用IL-7Rα抗体对Ⅱ型胶原诱导性关节炎(collagen-induced arthritis,CIA)T细胞的作用机制。采用Ⅱ型胶原(collagenⅡ,CⅡ)免疫DBA/1J小鼠建立CIA模型,二次免疫后分别对治疗组和对照组小鼠给予IL-7Rα抗体及其同型对照抗体进行治疗。通过HE染色检测小鼠关节炎性细胞浸润程度;3 H-TdR掺入法检测小鼠脾脏单个核细胞和CD4+T细胞对CⅡ的增殖反应;ELISA检测脾脏单个核细胞培养上清中细胞因子分泌情况;流式细胞术检测小鼠T细胞亚群分布变化情况;real-time PCR检测相关细胞因子及T细胞亚群转录因子mRNA表达水平。实验结果显示:治疗组小鼠关节炎症细胞浸润程度明显减轻;脾脏单个核细胞及CD4+T细胞增殖程度显著降低;脾脏单个核细胞培养上清中的炎性细胞因子IFN-γ、IL-17A、TNF-α含量明显低于对照组;Th1和Th17细胞亚群数量及相应的转录因子mRNA水平明显降低。以上结果提示应用IL-7Rα抗体治疗可能通过抑制致病性T细胞的增殖、减少致病性T细胞数量等途径缓解CIA发病。本研究阐明了IL-7Rα作为拮抗剂治疗CIA的作用机制,并为临床治疗类风湿性关节炎提供了研究基础。

To study the mechanism of IL-7Rα antibody to T cells from collagen-induced arthritis （CIA）, the CIA mouse model was established by immunization of mice with collagen Ⅱ（CⅡ）. The treatment group and the control group of mice were given IL 7Rα antibody and its isotype control antibody respectively after the secondary immunization. Infiltration of inflammatory cells in the joints was examined by HE staining. Proliferative responses of mononuclear cells and CD4＋ T cells from the spleens of two groups were examined by ^3H-TdR incorporation assay. We also tested the concentration of cytokines in the culture supernatant of splenocytes by ELISA and the pattern of T cell subsets distribution by flow cytometry. Moreover, the mRNA expression of the related cytokines and T cell subset transcription factors were examined by real-time PCR. The results showed that infiltration of inflammatory cells in ioints from the treatment group was reduced. IL-TRα antibody not only could inhibit the proliferation of mononuclear cells and CD4＋T cells from splenocytes, but also reduce the levels of inflammatory cytokines and the number of Thl and Th17 subsets. These results indicate that IL-7Rα antibody treatment may alleviate clinical symp-toms of CIA through inhibiting pathogenic T cell proliferation and reducing the amount of inflammatory T cell subsets. This study has elucidated the mechanism by which antibody to 1L-17Rα alleviates CIA symptom, and this may be used as basis for clinical therapy of rheumatoid arthritis.