Jessop H L, Lambert P A
J Gen Microbiol. 1986 Sep;132(9):2505-14. doi: 10.1099/00221287-132-9-2505.
Two O14:H12 strains of Serratia marcescens with different sensitivities to killing by normal pooled human serum were investigated. Complement binding, studied by measuring hydrophobicity and using rocket immunoelectrophoresis with anti-human C3, showed the sensitive cells (S1220) rapidly bound and fixed complement whereas the resistant cells (4444-60) bound less C3b. The strains had identical membrane protein composition. Crossed immunoelectrophoresis suggested that in S1220 cells the polysaccharide material including LPS was less antigenic and present in smaller amounts than in 4444-60 cells. This was confirmed by examining extracted polysaccharide material chemically and by SDS-PAGE. The resistant strain had 33% more phenol-extractable polysaccharide material than the sensitive strain, possibly comprising LPS with longer O antigen chain lengths, or a microcapsule of O antigen polysaccharide. Extra polysaccharide material on the surface of the resistant strain prevents complement components binding and reaching the hydrophobic membrane where lytic lesions occur.
对两株对正常人混合血清杀伤敏感性不同的粘质沙雷氏菌O14:H12菌株进行了研究。通过测量疏水性以及使用抗人C3的火箭免疫电泳研究补体结合，结果显示敏感细胞（S1220）能快速结合并固定补体，而抗性细胞（4444 - 60）结合的C3b较少。这两株菌具有相同的膜蛋白组成。交叉免疫电泳表明，在S1220细胞中，包括脂多糖在内的多糖物质抗原性较低，且含量比4444 - 60细胞中的少。通过化学分析提取的多糖物质以及SDS - PAGE对此进行了证实。抗性菌株比敏感菌株具有多33%的可酚提取多糖物质，可能是由O抗原链更长的脂多糖或O抗原多糖微胶囊组成。抗性菌株表面额外的多糖物质可阻止补体成分结合并到达发生裂解损伤的疏水膜。
