Hamadeh R M, Estabrook M M, Zhou P, Jarvis G A, Griffiss J M
Centre for Immunochemistry, University of California, San Francisco, USA.
Infect Immun. 1995 Dec;63(12):4900-6. doi: 10.1128/iai.63.12.4900-4906.1995.
alpha 1,3-Galactosyl antibodies (anti-Gal) are ubiquitous natural human serum and secretory polyclonal antibodies that bind to terminal galactose-alpha 1,3-galactose (alpha-galactosyl) residues. Serum immunoglobulin G (IgG) anti-Gal can block alternative complement pathway-mediated lysis of representative gram-negative enteric bacteria that bind it to lipopolysaccharide alpha-galactosyl structures, thereby promoting survival of such bacteria in the nonimmune host. We wanted to know whether anti-Gal also could bind to the lipooligosaccharides (LOS) of Neisseria meningitidis. To our surprise, we found that serum and secretory anti-Gal bound to pili but not to LOS of certain strains. This suggested the presence of an immunogenic pilus carbohydrate epitope. Mild periodate oxidation of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated outer membrane preparations from strains that bound anti-Gal followed by labeling of the neoaldehyde groups resulted in the labeling of bands that corresponded to pilin and LOS, confirming that pilin contains carbohydrate structures. A Bandeiraea simplicifolia lectin that also binds terminal alpha 1,3-galactosyl residues also bound to pilin. Serum IgG, IgA, and IgM anti-Gal as well as colostral secretory IgA anti-Gal bound to pilin, as judged by immunoblotting, and to the pili of intact piliated organisms, as judged by immunoelectron microscopy. Total serum anti-Gal (IgG, IgA, and IgM) and purified serum IgA1 anti-Gal, but not its purified IgG isotype, blocked complement-mediated lysis of a piliated meningococcal strain that bound anti-Gal to its pili. Colostral anti-Gal secretory IgA blocked killing of the same strain. Thus, anti-Gal IgA may promote disease when it binds to the pili of N. meningitidis strains.
α1,3-半乳糖基抗体（抗Gal）是普遍存在于人体血清和分泌物中的多克隆抗体，可与末端半乳糖-α1,3-半乳糖（α-半乳糖基）残基结合。血清免疫球蛋白G（IgG）抗Gal可阻断替代补体途径介导的对具有代表性的革兰氏阴性肠道细菌的裂解，这些细菌将其与脂多糖α-半乳糖基结构结合，从而促进此类细菌在非免疫宿主中的存活。我们想知道抗Gal是否也能与脑膜炎奈瑟菌的脂寡糖（LOS）结合。令我们惊讶的是，我们发现血清和分泌型抗Gal与某些菌株的菌毛结合，但不与LOS结合。这表明存在一种免疫原性菌毛碳水化合物表位。对结合抗Gal的菌株进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分离的外膜制剂进行轻度高碘酸盐氧化，然后对新醛基进行标记，结果导致与菌毛蛋白和LOS相对应的条带被标记，证实菌毛蛋白含有碳水化合物结构。一种也能结合末端α1,3-半乳糖基残基的单叶豆凝集素也与菌毛蛋白结合。通过免疫印迹判断，血清IgG、IgA和IgM抗Gal以及初乳分泌型IgA抗Gal与菌毛蛋白结合，通过免疫电子显微镜判断，与完整菌毛生物体的菌毛结合。血清总抗Gal（IgG、IgA和IgM）和纯化的血清IgA1抗Gal，但不是其纯化的IgG同种型，可阻断补体介导的对一种将抗Gal结合到其菌毛上的菌毛化脑膜炎球菌菌株的裂解。初乳抗Gal分泌型IgA可阻断对同一菌株的杀伤。因此，抗Gal IgA与脑膜炎奈瑟菌菌株的菌毛结合时可能会促进疾病发生。
