REGULATION OF THE POLYMERIC IMMUNOGLOBULIN RECEPTOR

聚合免疫球蛋白受体的调节

• 批准号: 3459843
• 负责人: Charlotte S Kaetzel
• 金额: $ 9.15万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1995-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3459843
• 关键词: AIDS; antibody receptor; bactericidal immunity; cell differentiation; genetic transcription; hormone regulation /control mechanism; immunoglobulin A; immunoglobulin genes; immunoregulation; interferons; intestinal mucosa; membrane activity; messenger RNA; plasmids; polymers; posttranscriptional RNA processing; reporter genes; secretory immune system; transfection; tumor necrosis factor alpha

Secretory immunoglobulin A is the first line of immune defense, protecting the mucous membranes of the gastrointestinal and respiratory tracts against ingested and inhaled pathogens. The transport of secretory IgA into external fluids is mediated by the polymeric immunoglobulin receptor (poly- Ig-R) on the surface of mucosal epithelial cells. Because of its key role in mucosal immunity, the proposed experiments will explore the regulation of poly-Ig-R expression in a subclone of the human HT-29 colon carcinoma cell-line, HT-29.74, which undergoes enterocytic differentiation when cultured in medium devoid of glucose. Expression of poly-Ig-R by HT-29.4 cells is increased dramatically during differentiation and by treatment with cytokines such as interferon-gamma and tumor necrosis factor-alpha. Three specific aims are proposed to determine the molecular mechanisms by which poly-Ig-R is regulated during differentiation of intestinal epithelial cells and by the action of specific immune modulators. First, the effects of the immune modulators interferon-gamma and tumor necrosis factor-alpha on steady-state levels of poly-Ig-R mRNA poly-Ig-R protein at specific stages of differentiation of HT-29.74 cells will be determined. Next, the contribution of transcriptional and post-transcriptional regulation will be assessed by measuring in vitro rates of poly-Ig-R gene transcription and stability of poly-Ig-R mRNA. Finally, specific cis- acting DNA elements in the poly-Ig-R gene which mediate its transcriptional regulation will be identified by 1) constructing chimeric plasmids in which fragments of the proximal 5'-flanking region of the poly-Ig-R gene have been inserted upstream of a reporter gene; 2) transfecting these plasmids into HT-29.74 cells; and 3) determining the effects of enterocytic differentiation and treatment with immune modulators on transcription of the reporter gene. The proposed experiments offer the potential for identifying novel regulatory mechanisms which control the differentiation- specific and cytokine-induced expression of poly-Ig-R. In addition, the proposed studies have the potential to add to our understanding of the molecular mechanisms by which cytokines in general regulate immune responses. Increased understanding of mechanisms regulating immune responses in the gut, including the effects of interferon-gamma and tumor necrosis factor-alpha, may offer new insights that could lead to better prevention and treatment of infectious diseases of mucosal surfaces, including AIDS.

分泌型免疫球蛋白A是免疫防御的第一道防线， 胃肠道和呼吸道的粘膜， 摄入和吸入的病原体。 分泌型伊加转运到 外部流体是由多聚免疫球蛋白受体（多聚 Ig-R）在粘膜上皮细胞表面的表达。 由于其关键作用 在粘膜免疫中，拟议的实验将探索调节 人HT-29结肠癌亚克隆中poly-Ig-R表达的研究 细胞系HT-29.74，其在以下情况下经历肠细胞分化： 在没有葡萄糖的培养基中培养。 HT-29.4表达poly-Ig-R 细胞在分化过程中显著增加， 用细胞因子如干扰素-γ和肿瘤坏死因子-α。 提出了三个具体的目标，以确定分子机制， 其中poly-Ig-R在肠上皮细胞分化过程中受到调节， 上皮细胞和通过特异性免疫调节剂的作用。 第一、 免疫调节剂干扰素-γ和肿瘤坏死的影响 α因子对聚-Ig-R mRNA聚-Ig-R蛋白稳态水平的影响 将确定HT-29.74细胞分化的特定阶段。 接下来，转录和转录后的贡献 将通过测量多聚-Ig-R基因的体外速率来评估调节 转录和稳定性。 最后，具体的顺- 在poly-Ig-R基因中的作用DNA元件，其介导其转录 调控将通过1）构建嵌合质粒来鉴定，其中 聚-Ig-R基因的近端5 ′-侧翼区的片段具有 插入到报告基因的上游; 2）分离这些质粒 HT-29.74细胞;和3）确定肠细胞的作用 分化和用免疫调节剂治疗对转录的影响 报告基因。 拟议的实验提供了潜在的 确定控制分化的新的调节机制- 特异性和甘氨酸诱导的poly-Ig-R表达。 此外该 拟议的研究有可能增加我们对 细胞因子一般调节免疫的分子机制 应答 增强对免疫调节机制的理解 肠道反应，包括干扰素-γ和肿瘤的影响 坏死因子-α，可能提供新的见解，可能导致更好的 预防和治疗粘膜表面的感染性疾病， 包括艾滋病。