BACTERIAL POLYSACCHARIDE CROSS-REACTIVE WITH MENINGOCOCCAL GROUP A POLYSACCHARIDE

与其他有包膜的细菌病原体相似， 多糖抗体赋予对侵袭性脑膜炎球菌的免疫力 疾病 A群脑膜炎球菌病有不同的流行病学 模式比其他两个主要的致病性脑膜炎球菌群B和C。 在中部非洲，A组脑膜炎是一种流行病，发病率很高; 在世界其他地区，A群脑膜炎球菌引起流行病。 无论是 在这种情况下，A组微生物的无症状携带率很低。 在 美国，A组脑膜炎球菌脑膜炎或携带几乎已经 过去35年来一直不为人知。 然而，大多数儿童和成人 A群脑膜炎球菌抗体的保护水平。 调查以 阐明这种对A群脑膜炎球菌的"天然"免疫力的起源 发现11 E。来自埃及的645份粪便样本的大肠杆菌菌株交叉反应 A群脑膜炎球菌感染 交叉反应抗原为K51和 K93荚膜多糖。杆菌 随后，K93和K51 通过抗血清琼脂技术鉴定的菌株， 从NIH临床中心的患者中分离的菌株， 从哥本哈根的孩子身上分离出来 分离得到K多糖 并鉴定了它们的结构：K93：3）-D-Gal-（1 - 4）-D-GlcUA-（1-， 在半乳糖苷基和K51的0 - 5和0 - 6处乙酰化：3）-D-GlcNac-1-PO4， 乙酰化在0 - 6。 K93与A组之间的交叉反应 脑膜炎球菌多糖是出乎意料的，因为它们不共享 单糖组分。 用E.大肠杆菌K93或K51 菌株诱导产生抗A群的杀菌和沉淀抗体 脑膜炎球菌 K93和K51 E。大肠杆菌菌株不合成 肠毒素，并且在体外测定中是非侵入性的。 吸收研究， 使用来自注射A组的个体的免疫前和免疫后血清 脑膜炎球菌多糖疫苗，计划研究起源和 "天然"和免疫诱导A群脑膜炎球菌的特异性 美国和非洲居民的抗体。

Similar to other encapsulated bacterial pathogens, serum anti-capsular polysaccharide antibodies confer immunity to invasive meningococcal diseases. Group A meningococcal diseases have a different epidemiological pattern than the other two major pathogenic meningococcal Groups B and C. In central Africa, Group A meningitis is endemic with a high frequency; in other parts of the world, Group A meningococci causes epidemics. In both situations, asymptomatic carriage of Group A organisms is low. In the U.S., Group A meningococcal meningitis or carriage have been virtually unknown for the past 35 years. Yet, most children and adults have protective levels of Group A meningococcal antibodies. Investigations to elucidate the origin of this "natural" immunity to Group A meningococcus revealed 11 E. coli strains of 645 stool samples from Egypt cross-reactive with meningococcal Group A. The cross-reactive antigens were the K51 and K93 capsular polysaccharides of these E. coli. Subsequently, K93 and K51 strains, identified by the antiserum agar technique, were found among isolates from patients at the Clinical Center, NIH, and in a study of stool isolates from children in Copenhagen. The K polysaccharides were isolated and their structures elucidated: K93: 3)-D-Gal-(1-4)-D-GlcUA-(1-, acetylated at 0-5 and 0-6 of the galatosyl and K51: 3)-D-GlcNac-l-PO4, acetylated at 0-6. The cross-reaction between the K93 and the Group A meningoccal polysaccharide was unexpected since they share no monosaccharide components. Immunization of rabbits with E. coli K93 or K51 strains induced bactericidal and precipitating antibodies to Group A meningococci. These K93 and K51 E. coli strains did not synthesize enterotoxins and were non-invasive in in vitro assays. Absorption studies, using pre and post immune sera from individuals injected with the Group A meningococal polysaccharide vaccine, are planned to study the origin and specificity of "natural" and immunization-induced Group A meningococcal antibodies in inhabitants of the U.S. and Africa.