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， 增加的关注，由于：1）抗生素耐药性肠 病原体和革兰氏阴性细菌脓毒症的威胁; 2） 南美的意外霍乱疫情; 3）突出的 细菌性腹泻是婴儿的杀手; 4） 结核病引起的抗药性变种;和5）继续 艾滋病毒感染的传播。 因为我们还不完全了解 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，以了解导致 粘膜免疫反应：1）试图阐明，在细胞和 分子遗传水平，派伊尔集合淋巴结（PP）的作用（聚集的 肠壁中的淋巴滤泡） 体液粘膜免疫应答的发展; 2）定义 细胞/细胞和细胞/细胞因子的交换， 我们的B和T淋巴细胞加上树突状细胞培养物在产生一个 IgA抗体应答; 3）评估B2 （滤泡）与全身性B细胞B1亚群对保护粘膜 免疫反应;和4）分析调节宿主免疫反应的机制。 对肠道革兰氏阴性菌和兼性， 细胞内革兰氏阳性病原体，如李斯特菌，通过 粘膜途径。 我们计划使用无菌和无抗原（Ag）的小鼠， 对于分析急性、新生肠道粘膜非常有用 反应，和新一代的体外功能测定，我们 最近开发了：1）PP和固有层组织碎片 检测，其报告组织免疫时肠道的免疫状态。 采样;和2）单/克隆B细胞微量培养，揭示了 Ig同种型电位、频率和Ag特异性B的生理状态 细胞 这些应该使我们能够实现我们的目标，例如， 让我们可以量化时间波动和下落 Ag特异性IgA记忆细胞、IgA前浆母细胞和IgA浆细胞 在肠道病毒、细菌或 毒素系统与粘膜的交叉调节和刺激 在我们的系统中也可以检查隔间。 最后，我们计划 探索粘膜如何对一种新的抗原作出反应， 大量的各种各样的环境抗原，可能不同于 更好地了解全身免疫反应。

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.