Analysis of regulatory mechanisms for HMGB1 secretion and signal transduction and their clinical significance

我们分离了高迁移率族（HMG）非组蛋白染色体蛋白1和2本研究发现，抗HMGB 1单克隆抗体FBH 7的主要B细胞表位是由52-56位氨基酸残基组成的组合结构，并且该部分在嗜中性粒细胞衍生的和淋巴细胞衍生的HMGB 1之间是不同的（J.Biochem.136; 155，2004）。我们还分析了HMGB 1表位，这些表位被来自各种自身免疫性疾病患者的血清抗体所识别：风湿性疾病，炎症性肠病和自身免疫性肝病。虽然我们还没有完成表位定位，但迄今为止获得的数据表明，一些血清识别相似的表位。我们发现HMGB 112 -20的9-mer显示出与已知的CTL表位p17-WT相似的亲和力。这些结果提示HMGB 1可诱导HLA-A2.1特异性CTL。我们还建立了一种新的致死性小鼠模型，其中90%的肝血流被手术阻断。所有小鼠在结扎后60小时死亡，平均存活时间为30小时。这些小鼠显示血清HMG 1水平升高，并且通过同时腹膜内注射单克隆抗HMG 1抗体提高了存活率（J. Surg.Res.124：59，2005）。综上所述，这些数据表明，HMG 1蛋白可能在某种致命性疾病中发挥重要作用，而血清HMG 1水平的干预可能成为这种临界状态的新策略。为此，我们开始建立一种可以有效吸收HMGB 1的生物膜。

We isolated high mobility group (HMG) nonhisitone chromosomal proteins 1 and 2 (HMGB1/HMGB2) as target antigens of anti-neutrophil cytoplasmic antibody, and have been analyzing the roles of those autoantibodies as well as the autoantigens.In this study, we found that the major B-cell epitope of a monoclonal anti-HMGB1 antibody, FBH7, is a combinatorial structure which is constructed by amino acid residue 52-56, ant that this portion is different between neutrophil-derived and lymphocyte-derived HMGB1 (J.Biochem.136;155,2004). We also analyzed the HMGB1 epitopes that were recognized by serum antibodies derived from patients with various autoimmune diseases : rheumatic diseases, inflammatory bowel diseases, and autoimmune liver diseases. Although we have not completed the epitope mapping, data obtained so far indicate that some sera recognize the similar epitope.The T-cell epitope of HMGB1 was investigated by measuring the affinity to bind to HLA-A2.1. We revealed that the 9-mer of HMGB1 12-20 showed the similar affinity as a well-known CTL epitope, p17-WT. These results suggest that HMGB1 may induce CTL restricted to HLA-A2.1.We also established a novel fatal mouse model, in which 90% of the hepatic blood flow was blocked by a surgical procedure. All mice died 60 hr after the ligation with a median survival time of 30 hr. These mice showed an elevated level of serum HMG1, and the survival rate increased by a simultaneous i.p.injection of monoclonal anti-HMG1 antibody (J.Surg.Res.124:59,2005). Taken together, these data indicates that HMG1 protein may play an important role in a certain fatal condition, and that the intervention of serum HMG1 levels may serve as a new strategy for such a critical state. For that purpose, we started to establish a biological membrane that can absorb HMGB1 effectively.