Characterization of CCR5-like Molecules in Leishmania

利什曼原虫中 CCR5 样分子的表征

• 批准号: 7686819
• 负责人: LYNN SOONG
• 金额: $ 22.65万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7686819
• 关键词: Antibodies; Area; Binding; Biological; Biological Assay; Biology; CCR; CCR5 gene; Cells; Cellular Immunity; Chemotaxis; Complex; Cutaneous; Cutaneous Leishmaniasis; DNA Viruses; Data; Defect; Diffuse Cutaneous Leishmaniasis; Disease Outcome; Disease Progression; Ensure; Evaluation; Foundations; Genes; Goals; Grant; Healed; Homing; Homologous Gene; Human; Immune response; Immunology; Immunoprecipitation; In Situ; Inbred Strains Mice; Infection; Inflammatory; Interferons; Interleukin-12; Investigation; Knowledge; Leishmania; Leishmaniasis; Lesion; Ligand Binding; Ligands; Link; Mediating; Molecular; Molecular Biology; Molecular Mimicry; Mus; Nature; Nodule; Parasites; Predisposition; Production; Proteins; Reagent; Recombinant Proteins; Research; Reverse Transcriptase Polymerase Chain Reaction; Risk; Schistosoma mansoni; Solid; South America; Specificity; System; Testing; Time; Toxoplasma gondii; Viral; Virus Diseases; Western Blotting; base; beta-Chemokines; chemokine; chemokine receptor; cytokine; experience; healing; macrophage; mimicry; novel; pathogen; receptor; response; stable cell line

DESCRIPTION (provided by applicant): Leishmania infection can cause a broad spectrum of leishmaniases in humans. Although it is well known that host- and parasite-derived factors contribute to disease outcome, our knowledge about their molecular interactions is still relatively limited. The long-term goal of this application is to define the mechanism(s) underlying the host susceptibility to L. amazonensis (La) infection. A hallmark of cutaneous leishmaniasis associated with La infection is the profound deficiency in cellular immunity to the parasite. An insufficient production of Th1 cytokines and inflammatory CC-chemokines is correlated with disease progression in murine La infection. Our antibody- and ligand-based studies have revealed that lesional and cultured La and L. mexicana parasites can express CCR5-like molecules. These findings have led to the hypothesis that Leishmania parasites express one or more molecules that mimic and interfere with the host CCR5 system, thus promoting homing of parasites to their target cells and/or modulating chemokine responses in situ. This hypothesis will be tested concurrently in two Specific Aims. Aim 1 is to confirm the expression of CCR5-like molecules in different species/strains of Leishmania and to examine the biological relevance of their expression in host-parasite interaction. Our efforts will mostly be placed on conducting functional studies (Ca++ influx, chemotaxis and ligand binding/internalization assays) using murine and human CCR5 ligands, as well as ligands that do not bind to CCR5. Aim 2 is to characterize the gene encoding parasite-derived CCR5 and define the nature of these proteins. The gene encoding CCR5-like molecules will be used for sequence comparison with their mammalian or viral counterparts. Stable cell lines expressing LaCCR5 and antibodies specific to leishmanial CCR5-like proteins will be generated for re-evaluation in functional assays. This proposed study is novel and highly significant because, while solid evidence exists for molecular mimicry of host cytokines/chemokines and their receptors by many pathogens, including DNA viruses, Toxoplasma gondii, and Schistosoma mansoni, such mimicry has not been identified for trypanosomatids. The fact that reagents are in place, linked with the PI's experience in immunology and molecular biology, ensures the feasibility of this exploratory grant. If proven correct, this study would, for the first time, demonstrate the presence of a functional CCR5 homologue(s) in Leishmania parasites. This application would greatly extend our current understanding of Leishmania biology and lay the foundation for additional in-depth investigations of host-parasite interactions.

描述（由申请人提供）：利什曼原虫感染可在人类中引起广谱利什曼病。虽然众所周知，宿主和寄生虫衍生的因素有助于疾病的结果，但我们对它们的分子相互作用的了解仍然相对有限。本应用程序的长期目标是确定宿主对亚马逊乳杆菌（La）感染易感性的机制。与La感染相关的皮肤利什曼病的一个特点是对寄生虫的细胞免疫严重不足。Th1细胞因子和炎性cc趋化因子的产生不足与小鼠La感染的疾病进展相关。我们基于抗体和配体的研究表明，病变和培养的La和L. mexicana寄生虫可以表达ccr5样分子。这些发现导致了一种假设，即利什曼原虫表达一种或多种模仿和干扰宿主CCR5系统的分子，从而促进寄生虫归巢到靶细胞和/或原位调节趋化因子反应。这一假设将在两个具体目标中同时得到检验。目的1是确认ccr5样分子在不同利什曼原虫物种/菌株中的表达，并检查其表达在宿主-寄生虫相互作用中的生物学相关性。我们的工作将主要集中在使用小鼠和人类CCR5配体以及不与CCR5结合的配体进行功能研究（Ca++内流、趋化性和配体结合/内化分析）。目的2是表征编码寄生虫源性CCR5的基因，并确定这些蛋白的性质。编码ccr5样分子的基因将用于与哺乳动物或病毒对应的序列比较。将产生表达LaCCR5和利什曼ccr5样蛋白特异性抗体的稳定细胞系，以便在功能分析中重新评估。