BACTERIAL MEMBRANE PROTEINS IN GRAM-NEGATIVE SEPSIS

革兰氏阴性败血症继续导致大量发病率和死亡率。许多病理生理被认为是由毒性细菌细胞壁分子引起的，包括脂多糖（LPS），这些分子引起直接毒性和/或诱导继发性促炎反应。我们的初步数据表明，LPS从垂死的细菌释放到血液中，形成含有三种保守外膜蛋白（OMPs）的复合物，这些OMPs本身可能具有生物活性。这三种细菌膜蛋白分别为外膜蛋白A （OmpA）、肽聚糖相关脂蛋白（PAL）和鼠蛋白脂蛋白（MLP）。该提案的总体目标是评估OmpA， PAL和MLP在革兰氏阴性脓毒症中的作用，最终目标是制定一种用交叉反应抗omp抗体治疗脓毒症的策略。我们的第一个具体目标是扩大研究，表明有一种形式的PAL从细菌表面释放出来，与人类脂蛋白一起以低密度漂浮。我们的第三个具体目标是研究针对OmpA， PAL和MLP表位的单克隆和多克隆IgG结合和中和每种外膜蛋白的生物学效应以及促进LPS/OMP复合物的opsinophagocy吞噬的能力。我们最后的具体目的是研究针对OmpA、PAL和MLP的单克隆和多克隆免疫球蛋白G对两种革兰氏阴性感染模型的保护作用。这些研究应该促进我们对革兰氏阴性脓毒症病理生理学的基本认识。每个omp在革兰氏阴性菌的临床菌株中高度保守。因此，该项目的成功结果将为开发用于人类治疗败血症的抗omp抗体提供直接和即时的方法。

Gram-negative sepsis continues to cause substantial morbidity and mortality. Much of the pathophysiology is believed to be caused by toxic bacterial cell wall molecules, including lipopolysaccharides (LPS), that cause direct toxicity and/or induce a secondary pro-inflammatory response. Our preliminary data indicate that LPS is released from dying bacteria that blood in complexes that contain three conserved outer membrane proteins (OMPs), and that these OMPs may have biological activity themselves. The three bacterial membrane proteins have been identified as outer membrane protein A (OmpA), peptidoyglycan associated lipoprotein (PAL), and murein lipoprotein (MLP). The overall objective of the proposal is to evaluate the role(s) of OmpA, PAL, and MLP in Gram-negative sepsis, with the ultimate goal of developing a strategy of treating sepsis with cross-reacting anti-OMP antibodies. Our first specific aim is to expand studies suggesting that there is a form of PAL released from the bacterial surface that floats at low density together with human lipoproteins. Our third specific aim is to study monoclonal and polyclonal IgG directed to epitopes on OmpA, PAL, and MLP for their ability to bind and neutralize the biological effects of each outer membrane protein and to promote opsinophagocyosis of LPS/OMP complexes. Our final specific aim is to study the protective efficacy of monoclonal and polyclonal immunoglobulin G directed to OmpA, PAL, and MLP in two models of Gram-negative infection. The studies should advance our fundamental understanding of the pathophysiology of Gram-negative sepsis. Each of the OMPs are highly conserved amongst clinical strains of Gram-negative bacteria. Therefore, a successful outcome of the project would provide a direct and immediate approach to developing anti-OMP antibodies for human use for the treatment of sepsis.