Immune Responses to Schistosome Egg Antigens

对血吸虫卵抗原的免疫反应

• 批准号: 6767828
• 负责人: Donald A Harn
• 金额: $ 40.48万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6767828
• 关键词: Immune; Responses; Schistosome; Egg; Antigens

DESCRIPTION (provided by applicant): This new proposal focuses on how a defined schistosome Th2 PAMP activates and matures dendritic cells to DC2s which then drive adaptive Th2 biased CD4+ T cell responses. DCs are activated when cell surface receptors ligate pathogen associated molecular patterns (PAMPs). In general, PAMPs activate APCs to produce Type-l, pro-inflammatory mediators, driving DCs to a DC1-type. DC1s present peptide to naive CD4+ T cells inducing a Th1-type response (). In contrast, little is known about the molecular nature of Th2-PAMPs or the mechanism by which they activate DCs. Lacto-N-fucopentaose III (LNFPIII) is the first Th2 PAMP described from helminth parasites. This glycan contains the Lewis X trisaccharide. When presented as a conjugate on a carrier (LNFPIII-C), LNFPIII drives Th2 responses in vivo and activates immature DCs to functional DC2s in vitro. The overall goal of this proposal is to examine activation of DCs and macrophages by LNFPIII-C compared to the Th1 PAMP LPS, to gain an understanding of the biology of recognition and activation of these cells by a schistosome Th2 PAMP. Based on preliminary studies we hypothesize that LNFPIII-C requires Toll Like Receptor 4 (TLR4) and MD2 but not the TIR adaptor protein MyD88 to to drive DCs to DC2s. We will test this by generating DCs and macrophages from mice deficient inTLR4 and/or CD14, or MyD88. We will also use HEK293 cells singly or doubly transfected with TLR2, TLR4, MD2 and CD14 or use murine macrophages that are dominant negative mutants for the TIR adaptor proteins TIRAP and MyD88. We hypothesize that the MAP kinase ERK, NF-kB and PGE2 are required for LNFPIII-C activation of DCs and that there are additional signaling molecules and mediators differentially expressed in LNFPIII/Lewis X activated DCs. We will test these aspects using inhibitors and targeted microarray analysis. We believe that the pattern of activation of DCs in vitro by LNFPIII-C/Lewis X is representative of what occurs in vivo and will test this by examining the responses of endogenous splenic DCs. The ability of LNFPIll-C to activate macrophages is fucose dependent, with no apparent role for carrier molecules other than to present multiple copies of LNFPIII. However, because schistosome Lewis X is found on glycolipids as well as glycoproteins we propose experiments to test whether the presence of a glycolipid tail alters LNFPIII/Lewis X activation of DCs. The specific aims are: 1) Does LNFPIII-C activation of macrophages and maturation of DC2s require the TLR4 receptor complex and the T1R adaptor proteins?; 2) What signaling molecules and mediators are required or utilized by LNFPIII-C in activation of macrophages and maturation of DC2s; 3) Will LNFPIII-C/Lewis X drive similar patterns of DC activation in vivo. 4) Does the presence of a lipid tail on LNFPIII/Lewis X alter DC or macrophage recognition or activation.

描述(由申请人提供)：这项新的建议集中在定义的血吸虫Th2 PAMP如何激活和成熟树突状细胞到DC2，然后驱动适应性的Th2偏向的CD4+T细胞反应。当细胞表面受体连接病原体相关分子模式(PAMPs)时，DC被激活。一般来说，PAMP激活APC产生促炎介质L型，驱动DC向DC1型转化。DC1s呈递多肽给幼稚的CD4+T细胞，诱导Th1型反应()。相反，人们对Th2-PAMPs的分子性质或它们激活DC的机制知之甚少。乳糖-N-岩藻五糖III(LNFP III)是第一个从寄生虫中发现的Th2型PAMP。这种多糖含有Lewis X三糖。当作为载体(LNFP III-C)的结合物存在时，LNFP III在体内驱动Th2反应，并在体外激活未成熟的DC对功能DC2的反应。本提案的总体目标是比较LNFP III-C和Th1 PAMP内毒素对DC和巨噬细胞的激活作用，以了解血吸虫Th2 PAMP识别和激活这些细胞的生物学机制。根据初步研究，我们假设LNFPIII-C需要Toll样受体4(TLR4)和MD2，而不是TIR适配器蛋白MyD88来驱动DC向DC2分化。我们将通过从缺乏TLR4和/或CD14或MyD88的小鼠中产生DC和巨噬细胞来测试这一点。我们还将使用单独或双转染TLR2、TLR4、MD2和CD14的HEK293细胞，或使用TIR接头蛋白TIRAP和MyD88的显性阴性突变体的小鼠巨噬细胞。我们假设MAP激酶ERK、NF-kB和PGE2是LNFP III-C激活DC所必需的，并且在LNFP III/Lewis X激活的DC中还存在其他信号分子和介质的差异表达。我们将使用抑制剂和靶向微阵列分析来测试这些方面。我们认为，LNFP III-C/Lewis X体外激活DC的模式代表了体内发生的情况，并将通过检测内源性脾DC的反应来检验这一点。LNFP Ill-C激活巨噬细胞的能力是岩藻糖依赖的，除了呈现多个拷贝的LNFP III外，对载体分子没有明显的作用。然而，由于血吸虫Lewis X存在于糖脂和糖蛋白上，我们建议进行实验，以测试糖脂尾巴的存在是否会改变DC的LNFPIII/Lewis X激活。其具体目的是：1)LNFP III-C激活巨噬细胞和DC2成熟是否需要TLR4受体复合体和T1R适配蛋白？2)LNFP III-C在巨噬细胞激活和DC2成熟过程中需要或利用哪些信号分子和介质；3)LNFP III-C/Lewis X是否会在体内驱动类似的DC激活模式。4)LNFP III/Lewis X上脂尾的存在是否改变DC或巨噬细胞的识别或激活？