BASIC MECHANISMS OF GUT MUCOSAL IMMUNE RESPONSES

对有效的粘膜疫苗的需求已经得到了相当大的重视 引起更多关注的原因是：1)对抗生素具有耐药性的肠道细菌增加 病原体和革兰氏阴性细菌败血症的威胁；2) 南美洲意外的霍乱疫情；3)突出 细菌性腹泻是婴儿的杀手；4)婴儿腹泻发病率增加 由抗生素耐药变异引起的结核病；以及5)继续 艾滋病毒感染的传播。因为我们的理解还不完全 粘膜免疫反应的某些主要特征，试图 开发新的粘膜疫苗在很大程度上仍然是经验性的。我们计划 继续我们富有成效的计划，了解导致 粘膜免疫反应：1)试图阐明，在细胞和 分子遗传水平，Peyer氏斑(PP)的作用(聚集体 肠壁中的淋巴滤泡)。 体液粘膜免疫反应的发展；2)定义 解释疗效的细胞/细胞和细胞/细胞因子交换 我们的B和T淋巴细胞加树突状细胞培养在产生 免疫球蛋白抗体反应；3)评价B2的贡献 (滤泡)与全身B细胞B1亚群对粘膜的保护作用 免疫反应；以及4)分析调节宿主 肠粘膜对革兰氏阴性杆菌和兼性细菌的免疫应答 细胞内革兰氏阳性病原体，如李斯特氏菌，通过 粘膜进路。我们计划使用无菌和无抗原的小鼠，这是 对于分析急性新生的肠道粘膜是非常有用的 反应，和新一代体外功能分析，我们 最近发展出：1)PP和固有层组织碎片 检测，它报告肠道在组织形成时的免疫状态 2)单/克隆性B细胞微量培养，揭示了 银特异性B的Lg同型电位、频率和生理状态 细胞。这些应该使我们能够实现我们的目标，例如通过 使我们能够量化时间波动和下落 抗原特异的LGA记忆细胞、IgA前浆母细胞和LGA浆细胞 在受到肠道病毒、细菌或 毒素。全身与粘膜的交叉调节和刺激 在我们的系统中也可以检查车厢。最后，我们计划 探讨粘膜对一种新的Ag的反应是如何在 大量的环境AGS，可能不同于 更好地理解了全身免疫反应。

The need for efficacious mucosal vaccines has received considerably increased attention due to: 1) the rise in antibiotic resistant enteric pathogens and the threat of gram-negative bacterial sepsis; 2) the unexpected cholera epidemics in South America; 3) the prominence of bacterial diarrhea as a killer of infants; 4) the increased incidence of tuberculosis caused by antibiotic-resistant variants; and 5) the continued spread of HIV infections. Because of our still incomplete understanding of certain major features of the mucosal immune response, attempts to develop new mucosal vaccines are still largely empiric. We plan to continue our productive program to understand the mechanisms leading to a mucosal immune response by: 1) trying to elucidate, at cellular and molecular genetic levels, the role of Peyer's patch (PP) (aggregates of lymphoid follicles in the intestinal walls) germinal centers in the development of a humoral mucosal immune response; 2) defining the cell/cell and cell/cytokine exchanges that account for the effectiveness of our B- and T-lymphocyte plus dendritic cell cultures at generating an lgA antibody response; 3) evaluating the contributions of the B2 (follicular) vs. systemic B1 subsets of B cells to protective mucosal immune responses; and 4) analyzing mechanisms that regulate the host's mucosal immune response to enteric gram-negative bacteria and facultative, intracellular gram-positive pathogens, such as Listeria, infecting via the mucosal route. We plan to use germ-free and antigen (Ag)-free mice, which have been very informative for analyzing acute, de novo gut mucosal responses, and a new generation of in vitro functional assays which we have recently developed: 1) the PP and lamina propria tissue fragment assay, which reports the immune status of the gut at the time of tissue sampling; and 2) the single/clonal B cell microculture, which reveals the lg isotype potential, frequency, and physiologic state of Ag-specific B cells. These should permit us to address our aims, for instance by permitting us to quantitate the temporal fluctuations and whereabouts of Ag-specific lgA-memory cells, IgA-pre-plasmablasts, and lgA plasma cells following acute oral stimulation with enteric viruses, bacteria, or toxins. Cross regulation and stimulation of systemic vs. mucosal compartments can also be examined in our system. Finally, we plan to probe how a mucosal response to a novel Ag, given in the context of copious amounts of a wide array of environmental Ags, may differ from the better understood systemic immune response.