HUMAN LIPOPOLYSACCHARIDE-BINDING PROTEIN POTENTIATES BACTERICIDAL ACTIVITY OF HUMAN BACTERICIDAL PERMEABILITY-INCREASING PROTEIN
HUMAN LIPOPOLYSACCHARIDE-BINDING PROTEIN POTENTIATES BACTERICIDAL ACTIVITY OF HUMAN BACTERICIDAL PERMEABILITY-INCREASING PROTEIN
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DOI：
10.1128/iai.63.2.522-527.1995
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发表时间：
1995-02-01
影响因子：
3.1
通讯作者：
NOWAKOWSKI, G
中科院分区：
文献类型：
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作者：
HORWITZ, AH;WILLIAMS, RE;NOWAKOWSKI, G
来自中性粒细胞的人杀菌/通透性增加蛋白（BPI）和重组氨基末端片段rBPI（23）在体外和离体血浆或全血中与革兰氏阴性菌结合并对革兰氏阴性菌具有细胞毒性。为了在体内发挥细胞外杀菌剂的作用，rBPI（23）必须在脂多糖结合蛋白（LBP）存在下起作用，LBP也结合革兰氏阴性菌，但没有报道对革兰氏阴性菌具有细胞毒性。LBP在健康人中以5至10 μ g/ml存在，在脓毒症患者中以高得多的水平存在，介导对革兰氏阴性感染的促炎宿主应答。在这些先前观察的基础上，我们检测了重组LBP（rLBP）对rBPI（23）体外对大肠杆菌J5的杀菌活性的影响。生理浓度的rLBP（5 - 20 μ g/ml）几乎没有或没有杀菌活性，但在测定（i）固体培养基上CFU形式的细胞存活力或肉汤培养物中的生长和（ii）用BPI处理后的蛋白质合成的测定中，其杀菌或相关活性所需的BPI浓度降低了10，000倍。LBP还增强了BPI介导的E.大肠杆菌外膜对放线菌素D的透化作用可达100倍左右，但本身无透化活性。在最佳的增强条件下，需要少于100个BPI分子才能杀死单个E。coliJ 5细菌。
Human bactericidal/permeability-increasing protein (BPI) from neutrophils and a recombinant aminoterminal fragment, rBPI(23), bind to and are cytotoxic for gram-negative bacteria both in vitro and ex vivo in plasma or whole blood. To function in vivo as an extracellular bactericidal agent, rBPI(23) must act in the presence of the lipopolysaccharide binding protein (LBP), which also binds to but has no reported cytotoxicity for gram-negative bacteria. LBP, which is present at 5 to 10 mu g/ml in healthy humans and at much higher levels in septic patients, mediates proinflammatory host responses to gram-negative infection. On the basis of these previous observations, we have examined the effect of recombinant LBP (rLBP) on the bactericidal activity of rBPI(23) against Escherichia coli J5 in vitro. Physiological concentrations of rLBP (5 to 20 mu g/ml) had little or no bactericidal activity but reduced by up to similar to 10,000-fold the concentration of BPI required for bactericidal or related activities in assays which measure (i) cell viability as CFUs on solid media or growth in broth culture and (ii) protein synthesis following treatment with BPI. LBP also potentiated BPI-mediated permeabilization of the E. coli outer membrane to actinomycin D by about 100-fold but had no permeabilizing activity of its own. Under optimal conditions for potentiation, fewer than 100 BPI molecules were required to kill a single E. coli J5 bacterium.