高迁移率族盒蛋白1 (HMGB1)是一种内源性分子，在胁迫下可以释放到细胞外环境中(Andersson U et al. 2000;scaffold P et al. 2002;Bonaldi T et al. 2003;陈刚等2004;Bell CW et al. 2006;拜尔C等人2012;Yang H et al. 2013)。

通过表面等离子体共振(SPR)分析，重组HMGB1以浓度依赖的方式结合TLR4:LY96(MD2) (Yang H et al. 2010;Yang H et al. 2015)。结合需要在106位置的半胱氨酸，而C106A HMGB1突变体未能结合TLR4:LY96 (Yang H et al. 2010)。此外，C106A和C106S HMGB1未能刺激小鼠腹腔巨噬细胞释放TNF (Yang H et al. 2010)。研究发现HMGB1的活性依赖于23、45和106位(C23、C45和C106)半胱氨酸的氧化还原状态(Urbonaviciute V et al. 2009;et al. 2012, 2013;杨华等，2012,2013)。串联质谱分析显示，HMGB1的炎症活动既需要在C23和C45之间形成分子内二硫键，也需要C106的还原态(硫醇态，C106- sh) (Yang H et al. 2012;Venereau E et al. 2012)。在培养的人原代巨噬细胞和小鼠巨噬细胞样RAW 264.7细胞中，这些半胱氨酸被活性氧(ROS)终端氧化为磺酸盐(CySO3-)和完全还原为硫醇(CySH)都消除了HMGB1的细胞因子刺激活性(Yang H et al. 2012; Venereau E et al. 2012). Biosensor-based SPR analysis confirmed that only the disulfide bond (C23-S-S-C45)-containing HMGB1 binds to LY96 (MD2) with high affinity (apparent Kd = 12 nM) regardless of whether LY96 or HMGB1 was immobilized on the sensor chip (Yang H et al. 2015). Moreover, TLR4 and LY96 (MD2) were recruited into CD14-containing lipid rafts of mouse RAW264.7 macrophages after stimulation with HMGB1, suggesting that an optimal HMGB1-dependent TLR4 activation in vitro required the co-receptor CD14 (Kim S et al. 2013). In addition to stimulating cells by direct interaction with innate immune receptors, HMGB1 was found to form immunostimulatory complexes with cytokines and other endogenous and exogenous ligands such as bacterial lipopolysaccharide (LPS) (Youn JH et al. 2008; Wahamaa H et al. 2011; Hreggvidsdottir HS et al. 2009) HMGB1 in complex with LPS, IL1alpha or IL1beta boosted proinflammatory cytokine- and matrix metalloproteinase (MMP3) production in synovial fibroblasts obtained from rheumatoid arthritis (RA) and osteoarthritis (OA) patients (Wahamaa H et al. 2011; He ZW et al. 2013). HMGB1 was reported to associate and amplify the activity of LPS (TLR4 ligand), CpG-ODN (TLR9 ligand) or Pam3CSK4 (TLR1:TLR2 ligand) in a synergistic manner when added to the cultures of human peripheral blood mononuclear cell (PBMC) (Hreggvidsdottir HS et al. 2009).