Château M T, Caravano R
INSERM U65, Département de Biologie Santé, Université Montpellier II, France.
FEMS Immunol Med Microbiol. 1997 Jan;17(1):57-66. doi: 10.1111/j.1574-695X.1997.tb00996.x.
The bacterial and serum factors involved in the oxidative response triggered by Salmonella typhimurium in differentiated U937 cells were investigated. Complement activation was shown to be required, using sera deficient in complement factors. An original dot-blot technique was developed to study the activation of complement by either bacteria or purified lipopolysaccharide (LPS). Both O-specific and lipid A segments of LPS were found to play a role in the triggering of the oxidative response. Lipid A was responsible for bacterial C3-derived opsonization by inducing an antibody-independent activation of complement classical pathway, whereas O-specific polysaccharide chains (O-Ag) were involved in cellular activation. Inhibition experiments using anti-cell surface marker monoclonal antibodies showed the involvement of the alpha chain of CR3 (CD11b) in the oxidative response developed by differentiated U937 cells in response to S. typhimurium infection. Whether both iC3b and O-Ag interact with different domains of CR3 or whether the binding of O-Ag occurs via a not yet identified receptor remains to be determined.
研究了鼠伤寒沙门氏菌在分化的U937细胞中引发的氧化反应所涉及的细菌和血清因子。使用缺乏补体因子的血清表明补体激活是必需的。开发了一种原始的斑点印迹技术来研究细菌或纯化的脂多糖（LPS）对补体的激活作用。发现LPS的O特异性和脂质A部分在氧化反应的触发中均起作用。脂质A通过诱导补体经典途径的抗体非依赖性激活来负责细菌C3衍生的调理作用，而O特异性多糖链（O-Ag）参与细胞激活。使用抗细胞表面标志物单克隆抗体的抑制实验表明，CR3（CD11b）的α链参与了分化的U937细胞对鼠伤寒沙门氏菌感染产生的氧化反应。iC3b和O-Ag是否与CR3的不同结构域相互作用，或者O-Ag的结合是否通过尚未确定的受体发生，仍有待确定。
