Rajasekaran Narendiran, Wang Nan, Truong Phi, Rinderknecht Cornelia, Macaubas Claudia, Beilhack Georg F, Shizuru Judith A, Mellins Elizabeth D
Stanford University School of Medicine, Stanford, California 94305-5164, USA.
Arthritis Rheum. 2013 Mar;65(3):681-92. doi: 10.1002/art.37800.
In the K/BxN mouse model of inflammatory arthritis, T cells carrying a transgenic T cell receptor initiate disease by helping B cells to produce arthritogenic anti-glucose-6-phosphate isomerase (anti-GPI) autoantibodies. We found that lethally- irradiated lymphocyte-deficient C57BL/6 (B6).g7 (I-A(g7) +) recombinase-activating gene-deficient (Rag(-/-)) mice reconstituted with K/BxN hematopoietic stem and progenitor cells exhibit arthritis by week 4. In contrast, healthy B6.g7 recipients of K/BxN hematopoietic stem and progenitor cells show only mild arthritis, with limited extent and duration. The objective of this study was to investigate the factors responsible for the attenuation of arthritis in B6.g7 recipients.
Antibody responses were measured by enzyme-linked immunosorbent assay. Fluorescence-activated cell sorting analyses were performed for testing chimerism, expression of markers of activation and suppression, tetramer binding, and intracellular cytokines in CD4+ T cells. Suppressive activity of CD4+ T cells was studied by adoptive transfer.
Titers of anti-GPI antibodies in reconstituted B6.g7 mice were ∼60-fold lower than in reconstituted B6.g7 Rag(-/-) mice. Examination of chimerism in the reconstituted B6.g7 mice showed that B cells and myeloid cells in these mice were donor derived, but CD4+ T cells were primarily host derived and enriched for cells expressing the conventional regulatory markers CD25 and FoxP3. Notably, CD4+CD25-FoxP3- T cells expressed markers of suppressive function (CD73 and folate receptor 4), and delayed disease after adoptive transfer. Activation of donor-derived CD4+ T cells was reduced, and thymic deletion of these cells appeared increased.
Despite myeloablation, host CD4+ T cells having a regulatory phenotype emerge in these mice and attenuate autoimmunity.
在炎性关节炎的K/BxN小鼠模型中，携带转基因T细胞受体的T细胞通过帮助B细胞产生致关节炎的抗葡萄糖-6-磷酸异构酶（抗GPI）自身抗体引发疾病。我们发现，用K/BxN造血干细胞和祖细胞重建的经致死性照射的淋巴细胞缺陷型C57BL/6（B6）.g7（I-A(g7)+）重组激活基因缺陷型（Rag(-/-)）小鼠在第4周时出现关节炎。相比之下，接受K/BxN造血干细胞和祖细胞的健康B6.g7受体仅表现出轻度关节炎，程度和持续时间有限。本研究的目的是调查导致B6.g7受体中关节炎减轻的因素。
通过酶联免疫吸附测定法测量抗体反应。进行荧光激活细胞分选分析以检测嵌合现象、激活和抑制标志物的表达、四聚体结合以及CD4+ T细胞中的细胞内细胞因子。通过过继转移研究CD4+ T细胞的抑制活性。
重建的B6.g7小鼠中抗GPI抗体的滴度比重建的B6.g7 Rag(-/-)小鼠低约60倍。对重建的B6.g7小鼠的嵌合现象检查表明，这些小鼠中的B细胞和髓细胞是供体来源的，但CD4+ T细胞主要是宿主来源的，并且富含表达传统调节标志物CD25和FoxP3的细胞。值得注意的是，CD4+CD25-FoxP3- T细胞表达抑制功能标志物（CD73和叶酸受体4），并在过继转移后延迟疾病发生。供体来源的CD4+ T细胞的激活减少了，并且这些细胞的胸腺缺失似乎增加了。
尽管进行了骨髓消融，但这些小鼠中出现了具有调节表型的宿主CD4+ T细胞，并减轻了自身免疫。
