FUNCTIONS OF SHIGA LIKE TOXIN RECEPTORS IN IMMUNE RESPONSES

志贺样毒素受体在免疫反应中的功能

• 批准号: 6107390
• 负责人: MARK D MALONEY
• 金额: $ 5.64万
• 依托单位: SPELMAN COLLEGE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6107390
• 关键词: B lymphocyte; Escherichia coli; Escherichia coli infections; MHC class II antigen; SCID mouse; antigen antibody reaction; antigen presenting cell; bacterial toxins; biological signal transduction; cell sorting; cellular immunity; cellular pathology; cytokine; cytokine receptors; enzyme linked immunosorbent assay; glycosphingolipids; human tissue; humoral immunity; immunosuppression; laboratory mouse; model design /development; monoclonal antibody; receptor binding; receptor expression; thin layer chromatography

Shiga-like toxins (SLT's, also called verotoxins or VT's) produced by E. coli sertotype 0157;H7 and other serotypes have been implicated as causative agents of hemorrhagic colitis, thrombotic thrombocytopenic purpura and hemolytic uremic syndrome. The receptors for the SLT's are globotriaosyl ceramide or Gb3 (CD77) and possibly other glycosphingolipids which cotnain Galalpha1-4Gal residues. Gb3 is expressed on a wide variety of human cell types including germinal center B lymphocytes. The Gb3- binding SLT B subunits have been shown to mimic the 63 kD subunit of the human alpha-interferon receptor (IFNAR) and the pan B cell marker CD19 in their amino acid sequences. Experimental evidence to date supports a role for Gb3/IFNAR interaction in alpha-IFN signaling in some cell types and CD19/Gb3 interaction as a mechanism for homotypic adhesion and homing of B lymphocytes. The majority of human cells which express Gb3, including B lymphocytes, are capable of functioning as antigen-presenting cells. Therefore, SLT's may be a means by which enterohemorrhagic E. coli suppress antibody responses and other functions of the immune system during infection. The long term objectives of the proposed research are to determine the cellular functions of Gb3 and other Galalpha1-4Gal-containing glycolipids and their endogenous protein ligands and to determine how the targeting of Gb3 and other Galalpha1-4Gal-containing glycolipids and their endogenous protein ligands and to determine how the targeting of Gb3+ cells by SLT affects immune responses and athe pathogenesis of SLT-producing E. coli infection. Specific aims are to; 1. Define cell functions which involve Gb3 expression in human B cell lines and potential antigen-presenting cells. SLT's will be used as probes to further define Gb3 expression on B cell lines and to probe the effect of cytokines, antibodies to surface markers, mitogens and other inducers of differentiation or activation on Gb3 expression and SLT-induced cytotoxicity in B cells and other potential antigen presenting cells. Any differential effects of these agents on wild-type Gb3+ cells versus mutant cells selected to be Gb3 and Gb3-binding proteins in human B cell lines. Human B cell lines which are CD19+(e.g. Daudi) and CD19-(e.g. U266) will be injected into SCID mice to investigate a possible role for CD19/Gb3 interaction in homing to sites of high Gb3 expression. 3. Examine the potential of developing a mouse model for the cytotoxic effects of SLT and cellular functions of Gb3 with regard to cells of the immune system. The Gb3 expression and susceptibility to SLT-induced cytotoxicity of murine cell lines corresponding to different stages of B cell development as well as other murine cells capable of antigen presentation will be compared to the Gb3 composition of corresponding human cells. The responses elicited in mice by various antigens administered with SLT B subunits will determine whether the binding of B subunits to Gb3+ cells is immunosuppressive.

志贺样毒素（Shiga-like toxins，VT's）是由大肠杆菌产生的一类毒素。 大肠杆菌血清型0157;H7和其他血清型被认为是 出血性结肠炎的病原体，血栓性结肠炎 紫癜和溶血性尿毒症综合征。 这些受体是 globotriaosyl神经酰胺或Gb 3（CD 77）和可能的其他鞘糖脂 其包含Galalpha 1 -4Gal残基。 Gb 3在各种各样的 包括生发中心B淋巴细胞。 关于Gb 3- 已经显示，结合性β B亚单位模拟了β-半乳糖苷酶的63 kD亚单位。 人α-干扰素受体（IFNAR）和泛B细胞标志物CD 19， 它们的氨基酸序列。 迄今为止的实验证据支持了 在某些细胞类型中的α-IFN信号传导中的Gb 3/IFNAR相互作用， CD 19/Gb 3相互作用作为B细胞同型粘附和归巢的机制 淋巴细胞 大多数表达Gb 3的人类细胞，包括B 淋巴细胞能够作为抗原呈递细胞发挥功能。 因此，肠出血性大肠杆菌可能是一种途径。大肠杆菌抑制 抗体反应和免疫系统的其他功能 感染 拟议研究的长期目标是确定 Gb 3和其他含Galalpha 1 - 4Gal糖脂的细胞功能 和它们的内源性蛋白配体，并确定如何靶向 Gb 3和其他含Galalpha 1 - 4Gal的糖脂及其内源性 蛋白质配体，并确定如何靶向Gb 3+细胞通过 影响产生SLT的E.杆菌 感染 具体目标是： 1. 定义涉及人B细胞中Gb 3表达的细胞功能 细胞和潜在的抗原呈递细胞。 探针将用作探针 为了进一步确定Gb 3在B细胞系上的表达，并探索Gb 3在 细胞因子、表面标志物的抗体、有丝分裂原和其它细胞因子的诱导物， 分化或激活对Gb 3表达和SLT诱导的 在B细胞和其它潜在的抗原呈递细胞中的细胞毒性。 任何 这些试剂对野生型Gb 3+细胞与突变型Gb 3+细胞的不同作用 在人B细胞系中选择为Gb 3和Gb 3结合蛋白的细胞。 CD 19+（例如Daudi）和CD 19-（例如U266）的人B细胞系将被 注射到SCID小鼠中以研究CD 19/Gb 3的可能作用。 在归巢到高Gb 3表达位点中的相互作用。 3. 检查开发细胞毒性的小鼠模型的潜力 Gb 3对人结肠癌细胞的增殖和细胞功能的影响 免疫系统 Gb 3的表达和对SLT诱导的 对应于B的不同阶段的鼠细胞系的细胞毒性 细胞发育以及其他能够抗原 将呈现与相应的人的Gb 3组成进行比较。 细胞 通过施用的各种抗原在小鼠中引起的应答 将决定B亚基与β B亚基的结合是否 Gb 3+细胞具有免疫抑制作用。