Jarvis G A
Department of Laboratory Medicine, University of California, San Francisco.
Infect Immun. 1994 May;62(5):1755-60. doi: 10.1128/iai.62.5.1755-1760.1994.
The deposition and degradation of human complement component C3 on the cell surfaces of Neisseria meningitidis and Neisseria gonorrhoeae were studied. Bacteria were incubated in human serum, and ester-linked C3 fragments were analyzed by hydroxylamine release and immunoblot detection. Similar patterns of C3 degradation were found for both serum-resistant and serum-sensitive meningococcal strains of serogroups A, B, C, Y, and W135, as well as for serum-sensitive gonococcal strains and their sialylated serum-resistant variants. The predominant fragments in all cases were the 40-kDa alpha' 2 chain of iC3b and the 75-kDa beta chain common to both C3b and iC3b. The 67-kDa alpha' 1 chain of iC3b was also detected. The 105-kDa alpha' chain of intact C3b represented a minor proportion of deposited C3. Capsule-specific immunoglobulin G or immunoglobulin A1 did not alter the observed degradation patterns, nor did incubation of meningococci in properdin-deficient serum. The degradation of C3 in C5-, C6-, or C8-deficient serum was the same as that in normal serum, although the deposition of C3 was severely limited, based as indicated by the intensity of the fragments. With the use of an enzyme-linked immunosorbent assay that measured total iC3b and C3, I found that both iC3b deposition and C3 deposition varied among meningococcal and gonococcal strains and that the amounts of iC3b and C3 were independent of the relative quantities of cell surface sialic acid and of serum sensitivity for meningococci but not for gonococci. I conclude that complement activation on neisserial cell surface results in the formation of an identical repertoire of predominantly iC3b fragments of ester-linked C3b molecules regardless of the presence of sialic acid in either the capsule or the lipooligosaccharide or of the sensitivity of the organism to complement-mediated lysis but that the quantities of both ester- and amide-linked iC3b molecules deposited exhibit strain variability.
对人补体成分C3在脑膜炎奈瑟菌和淋病奈瑟菌细胞表面的沉积及降解进行了研究。将细菌与人血清一起孵育，通过羟胺释放和免疫印迹检测分析酯连接的C3片段。在血清抗性和血清敏感的A、B、C、Y和W135血清群脑膜炎球菌菌株中，以及血清敏感的淋球菌菌株及其唾液酸化的血清抗性变体中，发现了相似的C3降解模式。在所有情况下，主要片段是iC3b的40 kDa α' 2链以及C3b和iC3b共有的75 kDa β链。还检测到了iC3b的67 kDa α' 1链。完整C3b的105 kDa α'链在沉积的C3中占较小比例。荚膜特异性免疫球蛋白G或免疫球蛋白A1并未改变观察到的降解模式，在备解素缺陷血清中孵育脑膜炎球菌也未改变。在C5、C6或C8缺陷血清中C3的降解与正常血清中相同，尽管C3的沉积受到严重限制，这从片段的强度可以看出。使用测量总iC3b和C3的酶联免疫吸附测定法，我发现iC3b沉积和C3沉积在脑膜炎球菌和淋球菌菌株之间存在差异，并且iC3b和C3的量与细胞表面唾液酸的相对量以及脑膜炎球菌的血清敏感性无关，但与淋球菌的血清敏感性有关。我得出结论，无论荚膜或脂寡糖中是否存在唾液酸，也无论该生物体对补体介导的裂解的敏感性如何，奈瑟菌细胞表面的补体激活都会导致形成相同的主要为酯连接C3b分子的iC3b片段库，但沉积的酯连接和酰胺连接的iC3b分子的量均表现出菌株变异性。
