Different bacterial species selectively induce TH1 cells

不同菌种选择性诱导TH1细胞

• 批准号: 7446562
• 负责人: SANDRA C KIM
• 金额: $ 13.21万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7446562
• 关键词: Address; Adherence; Antigens; Bacteria; Bacterial Antigens; CD4 Positive T Lymphocytes; Cells; Chronic; Colitis; Crohn' s disease; Data; Disease; Distal; Engineering; Enterobacteriaceae; Enterococcus faecalis; Epithelial; Epitopes; Escherichia coli; Exhibits; Expression Library; HLA-B27 Antigen; Human; Immune; Immune response; Immunodeficient Mouse; Individual; Inflammation; Inflammatory disease of the intestine; Interferon Type II; Interferons; Interleukin-10; Intestines; Invasive; Kinetics; Mediating; Mesentery; Mucosal Immune Responses; Mus; Mutagenesis; Numbers; Patients; Phenotype; Recombinants; Relapse; Serological; T-Lymphocyte; Virulence Factors; Wild Type Mouse; commensal microbes; disease phenotype; duodenitis; germ free condition; in vivo; interest; lymph nodes; regional difference; response

DESCRIPTION (provided by applicant): Chronic relapsing intestinal inflammation appears to be mediated by dysregulated innate and acquired immune responses to commensal (nonpathogenic) enteric bacteria in genetically predisposed individuals. We hypothesize that (1) various non-pathogenic commensal bacteria induce distinct disease phenotypes in genetically susceptible hosts due to either regionally restricted mucosal immune responses to bacterial antigens or b. selective epithelial adherence/ invasion in different regions of the intestine, and (2) a discrete number of E.faecalis antigens induce dysregulated T cell immune responses, leading to the induction and perpetuation of chronic intestinal inflammation. These hypotheses are addressed in the following Specific aims: 1. Identify the mechanisms by which E.faecalis and E. coli, alone and in combination, induce different disease phenotypes in the same genetically susceptible host, the IL-10-/- mouse, by: a. Comparing virulence factors (epithelial adherence and invasion) of E. coli and E.faecalis shown to differentially induce distinct disease phenotypes in monoassociated IL-10-/- mice to known adherent/ invasive E. coli (AIEC) strains isolated from human Crohn's disease patients, and randomly isolated commensal E.coli and E.faecalis strains from SPF IL-10-/- mice with colitis and WT mice. b. Determining in vivo regional differences in mucosal adherence and invasion by each bacterial species in IL-10-/- mice co-colonized with these two bacterial species. c. Investigating the ability of adoptively transferred CD4+ cells isolated from colitic IL-10-/'- mice monoassociated with E. coli or E.faecalis to induce regionally specific intestinal inflammation and variable disease kinetics in immunodeficient mice colonized with either or both bacterial species. 2. Identify dominant E.faecalis antigens activating T cells in monoassociated IL-10-/- mice by: a. Determining the dominant antigens (identified in an expression library screened by serologic responses) that induce interferon-gamma (IFN-gamma) responses in CD4+ T cells from the mesenteric lymph nodes of E.faecalis - monoassociated IL-10-/- mice with colitis. b. Identifying the specific epitope(s) involved in immune activation and subsequent perpetuation of intestinal inflammation in IL-10-/- mice through truncation mutagenesis. c. Determining if recombinant nonpathogenic bacteria engineered to expressing the dominant E.faecalis epitope can induce T cell - mediated colitis and duodenitis.

描述（由申请人提供）： 慢性复发性肠道炎症似乎是由遗传易感个体对肠道细菌（非致病性）的先天性和获得性免疫应答失调介导的。我们假设：（1）由于对细菌抗原或B的区域限制性粘膜免疫应答，各种非致病性肠道细菌在遗传易感宿主中诱导不同的疾病表型。肠的不同区域中的选择性上皮粘附/侵袭，和（2）离散数量的粪肠球菌抗原诱导失调的T细胞免疫应答，导致慢性肠道炎症的诱导和持续。这些假设在以下具体目标中得到解决：1。确定粪肠球菌和肠球菌的作用机制。单独和组合的IL-10-/-大肠杆菌通过以下方式在相同的遗传易感宿主IL-10-/-小鼠中诱导不同的疾病表型： a.比较E.大肠杆菌和粪肠球菌显示在单相关IL-10-/-小鼠中与已知的粘附/侵袭性大肠杆菌差异诱导不同的疾病表型。大肠杆菌（AIEC）菌株，以及从患有结肠炎的SPF IL-10-/-小鼠和WT小鼠中随机分离的大肠杆菌和粪大肠杆菌菌株。 B.确定在与这两种细菌共定殖的IL-10-/-小鼠中每种细菌物种的粘膜粘附和侵袭的体内区域差异。 C.研究从结肠炎IL-10-/-小鼠分离的过继转移的CD 4+细胞与E.大肠杆菌或粪肠球菌的感染，以诱导区域特异性肠道炎症和可变的疾病动力学在免疫缺陷小鼠定殖的任一种或两种细菌物种。2.通过以下方法鉴定单相关IL-10-/-小鼠中激活T细胞的显性粪肠球菌抗原： a.确定在来自患有结肠炎的粪肠球菌单相关IL-10-/-小鼠的肠系膜淋巴结的CD 4 + T细胞中诱导干扰素-γ（IFN-γ）应答的显性抗原（在通过血清学应答筛选的表达文库中鉴定）。 B.通过截短诱变鉴定参与IL-10-/-小鼠中免疫激活和随后肠道炎症持续的特异性表位。 C.确定经工程改造以表达优势粪肠球菌表位的重组非致病性细菌是否可诱导T细胞介导的结肠炎和肠炎。