Chiang Kuei-Chen, Shimada Yayoi, Nakano Toshiaki, Lai Chia-Yun, Hsu Li-Wen, Goto Shigeru, Ohmori Naoya, Mori Kenji, Miyagi Takamitsu, Kawamoto Seiji, Ono Kazuhisa, Chen Chao-Long, Goto Takeshi, Sato Shuji
Kazusa Institute for Drug Discovery, Josai International University, Kisarazu, Chiba, Japan.
J Immunol. 2009 Apr 1;182(7):4282-8. doi: 10.4049/jimmunol.0800641.
We reported that anti-histone H1 autoantibody is one of the main immunosuppressive factors in serum that is induced after orthotopic liver transplantation in a rat tolerogenic model. We generated a novel anti-histone H1 IgM mAb produced by hybridoma 16G9 (16G9 mAb) that shows MLR-inhibitory activity. Identification of a functional epitope responsible for the immunosuppressive activity of 16G9 mAb may lead to the establishment of a novel therapeutic strategy. We used a combinatorial phage display peptide library to screen for peptides that bind to 16G9 mAb. Consequently, two peptides that bind to 16G9 mAb, SSV and LPQ, were selected from the library. The binding of 16G9 mAb to histone H1 was inhibited by SSV. SSV was recognized by rat tolerogenic post-orthotopic liver transplantation serum and the binding to SSV was inhibited by histone H1. Mice were immunized with keyhole limpet hemocyanin-conjugated SSV and LPQ. Abs induced by SSV immunization inhibited Con A-stimulated splenocyte proliferation, and the inhibition was neutralized by preincubation with SSV. Splenocytes stimulated by anti-CD3 Ab were inhibited by SSV-induced Abs using CFSE labeling. SSV immunization in rats before heterotopic heart transplantation resulted in significant prolonged allograft survival. These findings suggested that SSV is a functional histone H1-binding epitope for 16G9 mAb. SSV is capable of determining serum immunoreactivity against histone H1 as an index marker for tolerance. The inhibitory activity of SSV-induced Abs on blast cell proliferation and the prolonged graft survival that results from SSV immunization imply a potential for the development of an immunosuppressive vaccine.
我们报道，抗组蛋白H1自身抗体是大鼠耐受诱导模型原位肝移植后血清中主要的免疫抑制因子之一。我们制备了一种由杂交瘤16G9产生的新型抗组蛋白H1 IgM单克隆抗体（16G9 mAb），其具有混合淋巴细胞反应抑制活性。鉴定负责16G9 mAb免疫抑制活性的功能性表位可能会导致建立一种新的治疗策略。我们使用组合噬菌体展示肽库筛选与16G9 mAb结合的肽。结果，从该库中选择了两种与16G9 mAb结合的肽，即SSV和LPQ。SSV可抑制16G9 mAb与组蛋白H1的结合。SSV可被大鼠原位肝移植后的耐受血清识别，并且组蛋白H1可抑制其与SSV的结合。用钥孔血蓝蛋白偶联的SSV和LPQ免疫小鼠。SSV免疫诱导产生的抗体可抑制伴刀豆球蛋白A刺激的脾细胞增殖，并且通过与SSV预孵育可中和这种抑制作用。使用CFSE标记，SSV诱导的抗体可抑制抗CD3抗体刺激的脾细胞。大鼠在异位心脏移植前用SSV免疫可显著延长同种异体移植物存活时间。这些发现表明，SSV是16G9 mAb的功能性组蛋白H1结合表位。SSV能够将针对组蛋白H1的血清免疫反应性确定为耐受性的指标标志物。SSV诱导的抗体对母细胞增殖的抑制活性以及SSV免疫导致的移植物存活时间延长暗示了开发免疫抑制疫苗的潜力。
