SALIVARY IMMUNE RESPONSE TO COMMENSAL ORAL BACTERIA

对口腔共生细菌的唾液免疫反应

• 批准号: 2129982
• 负责人: MICHAEL F. COLE
• 金额: $ 19.3万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-12-01 至 1997-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2129982
• 关键词: SDS polyacrylamide gel electrophoresis; Streptococcus mitis; Streptococcus mutans; antibacterial antibody; antibody specificity; bactericidal immunity; blood; endopeptidases; enzyme linked immunosorbent assay; genetic strain; genotype; host organism interaction; human milk; human subject; humoral immunity; immunoglobulin A; immunoregulation; infant human (0-1 year); longitudinal human study; microorganism culture; oral bacteria; preschool child (1-5); restriction fragment length polymorphism; saliva; secretory immune system; western blottings

At birth pioneer bacterial colonize the mouth and are succeeded by other populations to form the normal flora which plays an important role in host defense by excluding exogenous pathogens. However, dental caries and periodontal disease, are caused by bacteria that are often isolated from the normal flora. Furthermore, some commensal bacteria are opportunistic pathogens that cause severe systemic disease when the immune system is compromised. Secretory immunoglobulin A (SigA) antibodies reactive with commensal bacteria are present in saliva but their impact ont he normal flora is not known. the objective of this competing continuation is to define the salivary immune response to commensal oral bacteria and studies will focus on the pioneer bacterium S. mitis biovar 1, and the late colonizer S. mutans, for the following reasons: (1) pioneer bacteria are the first to colonize the mucosal surfaces and to be exposed to the secretory immune system; (2) pioneer bacteria are exclusively streptococci of limited phenotype; (3) S. mitis biovar 1 is the principal pioneer Streptococcus; (4) the immune response to the "late" colonizing streptococcus S. mutans, which is exposed to a more developed secretory immune system, can be compared to the early response to the pioneer S. mitis biovar 1. Saliva, breast milk, cord blood, serum and isolates of S. mitis biovar 1 and S. mutans obtained from the infant-mother pairs during an ongoing longitudinal study and its extension to the third year of the infants' life will be analyzed to test the following hypothesis: Commensal bacteria colonize and persist in the mouth because they subvert SigA antibodies and/or because secretory antibodies are of low avidity, low level or the wrong specificities. The Specific Aims are as follows: Aim 1: Determine the incidence of pioneer viridans streptococci producing IgA1 protease. Isolates of pioneer streptococci will be incubated with IgA1 and IgA1 protease activity will be detected by SDS-PAGE to test the hypothesis that IgA1 protease is an ecological determinant in colonization by destroying the biological activity of SigA1 antibodies. Aim 2: Analyze the clonal diversity of S. mitis biovar 1 and S. mutans. Isolates of these streptococci obtained from the infant-mother pairs during the ongoing longitudinal study will be examined by DNA fingerprinting and ribotyping to test the hypotheses that: (a) there is limited genetic heterogeneity within the strains of these species in each infants mouth; (b) different infants harbor different genotypes of these species; (c) clonotypes of these species are stable in the mouth over time; (d) an infant acquires these bacteria from the mother. Aim 3: Analyze the diversity of secretory and systemic antibodies reactive with S. mitis biovar 1 and S. mutans. Saliva, breast milk, cord blood and serum obtained from the infant-mother pairs will be analyzed by Western blotting and by ELISA to test the hypotheses that: (a) antibodies reactive with S. mitis biovar 1 and S. mutans are composed of (1) cross-reactive antibodies induced by related oral and/or gut bacteria and (2) specific antibodies induced by colonization of the homologous strain; (b) antibody specificities differ in the secretory and systemic compartments of the humoral immune system. Aim 4: Analyze the avidity of SigA, SigA1, and SigA2 antibodies reactive with S. mitis biovar 1 and S. mutans. Chaotrope dissociation ELISA and immunoblots will be used to test the hypothesis that commensal bacteria induce low avidity SigA antibodies that do not exhibit affinity maturation and are ineffective in immune elimination of these bacteria.

在出生时，先锋细菌在口腔中定植， 种群，形成正常植物群，发挥重要作用， 通过排除外源病原体的宿主防御。 然而，龋齿 和牙周病，是由细菌引起的， 从正常的植物群中分离出来。 此外，一些细菌 机会性病原体导致严重的全身性疾病时， 免疫系统受损 分泌型免疫球蛋白A（SigA） 与唾液细菌反应的抗体存在于唾液中， 它们对正常植物群的影响尚不清楚。 的目的 竞争性的延续是定义唾液免疫反应， 口腔细菌和研究将集中在先锋细菌 S. mitis biovar 1和晚期定居者S.变种人，对于以下 原因：（1）先锋菌是最先在粘膜定植的细菌 表面和暴露于分泌免疫系统;（2）先锋 细菌仅为有限表型的链球菌;缓症 生物型1是链球菌的主要先驱;（4）免疫应答 到"晚期"殖民的街道。变形杆菌，暴露于 更发达的分泌免疫系统，可以与早期相比， 对先驱S.缓症菌生物变种1. 唾液、母乳、脐带 血液、血清和分离的S. mitis biovar 1和S.获得的变异株 在一项正在进行的纵向研究中， 将对婴儿生命的第三年进行分析， 以下假设：共生细菌定殖并持续存在于 口腔，因为它们破坏SigA抗体和/或因为分泌 抗体具有低亲合力、低水平或错误的特异性。 的 具体目标如下：目标1：确定先锋的发生率 产生IgA1蛋白酶的草绿色链球菌。 先锋分离株 链球菌将与IgA 1一起孵育，IgA 1蛋白酶活性将 通过SDS-PAGE检测，以检验IgA1蛋白酶是一种蛋白酶的假设。 生态决定因素在殖民地通过破坏生物 SigA1抗体的活性。 目的2：分析克隆多样性 S. mitis biovar 1和S.变异人 这些链球菌的分离株 在正在进行的纵向研究中， 通过DNA指纹分析和核糖体分型来检验假设 （a）在菌株中存在有限的遗传异质性， 这些物种在每个婴儿口中;（B）不同的婴儿港 这些物种的不同基因型;（c）这些物种的克隆型是 在口腔中随时间稳定;（d）婴儿从以下途径获得这些细菌： 母亲 目的3：分析分泌型和全身型的差异 与S. mitis biovar 1和S.变异体 唾液，乳房 从婴儿-母亲对中获得的乳汁、脐带血和血清将被 通过Western印迹和ELISA分析，以检验以下假设： (a)与S. mitis biovar 1和S.变异人由 （1）相关口服和/或肠道诱导的交叉反应性抗体 细菌和（2）由细菌定殖诱导的特异性抗体 同源菌株;（B）抗体特异性在分泌型和 体液免疫系统的全身区室。 目标4：分析 与S.缓症 biovar 1和S.变异体 离液解离ELISA和免疫印迹 将被用来检验假设，即肠道细菌诱导低 亲合力SigA抗体不表现出亲和力成熟， 对这些细菌的免疫消除无效。