Fick R B
Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City 52242.
Eur J Clin Microbiol Infect Dis. 1989 Jan;8(1):29-34. doi: 10.1007/BF01964117.
Immunoglobulin G (IgG) is quantitatively the predominent immunoglobulin protein in the distal airway of the human host. IgG enters the distal lung from circulating pools and plasma cells located largely in the interstitium. Although all four IgG subclasses are present in human lung secretions, only subclasses G3 and, to a lesser degree, G1 attach to pulmonary macrophage membrane receptors. IgG opsonic antibodies are essential for the optimal clearance of a very troubling pathogen. Pseudomonas aeruginosa. Nosocomial pneumonia caused by this gram-negative bacillus responds poorly to potent antimicrobial agents and is associated with a 70% mortality. To a great extent the morbidity and mortality resulting from nosocomial pneumonia caused by Pseudomonas spp. are attributable to ineffective humoral immune response to this bacterium. IgG2 antibodies in response to pseudomonal lipopolysaccharide are poorly opsonic in the macrophage system, and derepression of the potent pseudomonal elastase, an enzyme with broad substrate specificity, contributes to the disruption of other IgG antibodies.
免疫球蛋白G（IgG）在人体宿主远端气道中是含量占主导的免疫球蛋白蛋白。IgG从循环池和主要位于间质中的浆细胞进入远端肺。虽然所有四种IgG亚类都存在于人类肺分泌物中，但只有G3亚类以及程度较轻的G1亚类能附着于肺巨噬细胞膜受体。IgG调理素抗体对于清除一种非常棘手的病原体——铜绿假单胞菌至关重要。由这种革兰氏阴性杆菌引起的医院获得性肺炎对强效抗菌药物反应不佳，且死亡率为70%。在很大程度上，由假单胞菌属引起的医院获得性肺炎导致的发病率和死亡率可归因于对该细菌的体液免疫反应无效。针对铜绿假单胞菌脂多糖产生的IgG2抗体在巨噬细胞系统中调理作用较差，而具有广泛底物特异性的强效铜绿假单胞菌弹性蛋白酶的去抑制作用会导致其他IgG抗体的破坏。
