Role of Macrophage Costimulatory Molecules in Polymicrobial Sepsis

描述（由申请人提供）：脓毒症中的炎症主要由巨噬细胞活化程度控制。共刺激分子是适应性免疫中能够激活巨噬细胞的一类受体。通过CD154、CD28/CTLA4和LFA-1在活化的T细胞上连接表达CD40、CD80/CD86和ICAM的巨噬细胞，增加NF-kB DNA结合和C/EBPb刺激/抑制亚型的比例。这导致大量炎性细胞因子的产生增加。然而，在多微生物脓毒症期间，共刺激分子在先天免疫反应中的作用尚未得到很好的描述。我们最近描述了CD40- /-小鼠在NF-kB活性和刺激/抑制性C/EBPb比值降低的多微生物脓毒症中延迟死亡。我们现在提供的数据表明，中性粒细胞作为败血症先天免疫反应的主要组成部分，可以通过体外共刺激分子CD40、CD80/CD86和ICAM直接激活巨噬细胞。在体内，与WT小鼠相比，CD80/CD86-/-小鼠在CLP后的存活率有所提高。这与NF-kB、刺激/抑制性C/EBPb比值以及BAL和血浆中IL-6和IL-10水平的降低有关。与适应性免疫模型中报道的类似，抑制多种共刺激分子提供了额外的益处。与CD80/86-/-小鼠相比，CD40/CD80/CD86-/-小鼠和CD80/CD86-/-小鼠的ICAM中和均提高了CLP后的存活率。在脓毒症患者中，我们发现与健康对照相比，PMN表达CD28、CTLA4和CD154上调，单核细胞表达CD40、CD80/CD86和ICAM。此外，与健康对照相比，脓毒症患者中CD154、CD28、ICAM和CTLA4的可溶性同工型上调。此外，sCD28和sCD154的水平仅在非幸存者中上调，这表明它们可能作为疾病活动性的生物标志物。总之，这些结果表明共刺激分子在脓毒症中的重要作用。在本建议中，我们计划将这些意见扩展到：1。在小鼠多微生物脓毒症模型中表征CD40-CD154、CD80/CD86-CD28/CTLA4和ICAM-LFA-1系统的动力学和活性2。2 .通过新型CD40/CD80/CD86-/-小鼠测试多种共刺激分子在脓毒症中的抑制作用；充分评估共刺激分子在脓毒症和感染性休克患者体内和体外表达和活性的意义

DESCRIPTION (provided by applicant): Inflammation in sepsis is controlled primarily by the degree of macrophage activation. Costimulatory molecules are a class of receptors capable of macrophage activation in adaptive immunity. Ligation of macrophage expressed CD40, CD80/CD86 and ICAM by CD154, CD28/CTLA4 and LFA-1 on activated T- cells, increases NF-kB DNA binding and the ratio of stimulatory/inhibitory isoforms of C/EBPb. This results in increased production of numerous inflammatory cytokines. However, the role for costimulatory molecules in the innate immune response during polymicrobial sepsis is not well described. We recently described CD40- /- mice have delayed mortality with polymicrobial sepsis with attenuations in NF-kB activity and the ratio of stimulatory/inhibitory C/EBPb. We now present data that neutrophils, a main component of innate immune response in sepsis, can directly activate macrophages via engagement of the costimulatory molecules CD40, CD80/CD86 and ICAM in vitro. In vivo, CD80/CD86-/- mice have improved survival compared to WT mice after CLP. This was associated with a reduction in NF-kB, the ratio of stimulatory/inhibitory C/EBPb and levels of IL-6 and IL-10 in BAL and plasma. Similar to what has been reported in moels of adaptive immunity, inhibtion for multiple costimulatory molecules provided additional benefit. Both CD40/CD80/CD86-/- mice and ICAM neutralization in CD80/CD86-/- mice improved survival compared to CD80/86-/- mice after CLP. In humans with sepsis, we found upregulation of PMN expressed CD28, CTLA4 and CD154, and monocyte expressed CD40, CD80/CD86 and ICAM compared to healthy controls. In addition, the soluble isoforms of CD154, CD28, ICAM and CTLA4 were upregulated in septic patients compared to healthy controls. Furthermore, levels of sCD28 and sCD154 were only upregulated in non-survivors, suggesting a potential role as a biomarker of disease activity. Together, these results suggest an important role for costimulatory molecules in sepsis. In this proposal we plan to extend these observations to: 1. Characterize the kinetics and activity of the CD40-CD154, CD80/CD86-CD28/CTLA4 and ICAM-LFA-1 systems in a murine model of polymicrobial sepsis, 2. Test the effect of inhibition of multiple costimulatory molecules in sepsis via a novel CD40/CD80/CD86-/- mouse, and 3. To fully assess the significance of costimulatory molecule expression and activity both in vivo and ex vivo in humans with sepsis and septic shock