Protective Glycopeptide Immunodeterminants of Ehrlichia chaffeensis

描述（由申请人提供）：本研究项目的长期目标是了解埃里希体糖蛋白在对查菲埃里希体的保护性免疫中的作用。人嗜单核细胞埃立克体病（HME）是一种由专性胞内细菌埃立克体引起的、可危及生命的新型蜱传人畜共患病。chaffeensis。抗体在抗E. chaffeensis，但保护性抗原和参与保护性抗体应答的发展的表位仍然相对未知。在E. Chaffeensis中，引起强烈的抗体应答，包括GP 120、GP 200和GP 47，并且我们已经确定聚糖是重要的表位决定簇，其实质上有助于糖蛋白特异性抗体的发展。该提案的目标是从分子上定义E。chaffeensis gp 47糖肽表位，并确定糖蛋白特异性抗体在免疫中的作用。我们推测，许多引发保护性抗体的分子决定簇。chaffeensis由主要免疫反应性糖蛋白（包括gp 47）内的O-连接己糖糖肽定义。我们提出了以下具体目标来检验这一中心假设：1）定义E。chaffeensisgp 47聚糖组成、连接和附着位点，2）确定gp 47糖肽抗体的体内保护效力，和3）确定糖蛋白组在抗体识别和抗E.查菲线虫感染将通过气相色谱法和质谱法测定gp 47聚糖组成、连接和连接位点。探讨了gp 47中的一个主要糖肽抗体表位在抗体介导的抗E. chaffeensis将通过使用E.查菲菌感染，以确定抗糖肽和抗肽抗体提供的免疫力。E.将在SCID小鼠模型中确定查菲大肠杆菌糖蛋白组在开发保护性抗体中的作用，以评价由针对天然和聚糖改变的E. chaffeensis。该建议旨在进一步了解埃立克体糖蛋白及其在免疫中的作用。chaffeensis。HME是一个新兴的公共卫生问题，这项研究将促进疫苗和治疗方法的合理开发，以对抗北美最流行的威胁生命的蜱传疾病。

DESCRIPTION (provided by applicant): The long term goal of this research project is to understand the role of ehrlichial glycoproteins in protective immunity to Ehrlichia chaffeensis. Human monocytotropic ehrlichiosis (HME) is a life-threatening emerging tick-borne zoonosis caused by the obligately intracellular bacterium, E. chaffeensis. Antibody plays a substantial role in immunity to E. chaffeensis, but the protective antigens and epitopes involved in the development of a protective antibody response remain relatively unknown. Several glycoproteins have been identified in E. chaffeensis that elicit strong antibody response including the gp120, gp200 and gp47, and we have determined that glycans are important epitope determinants that contribute substantially to the development of glycoprotein specific antibody. The objectives of this proposal are to molecularly define the E. chaffeensis gp47 glycopeptide epitopes, and to determine the role of glycoprotein-specific antibodies in immunity. We hypothesize that many of the molecular determinants that elicit protective antibodies to E. chaffeensis are defined by O-linked hexose glycopeptides within major immunoreactive glycoproteins, including gp47. We propose the following specific aims to test this central hypothesis: 1) define the E. chaffeensis gp47 glycan compostion, linkage and attachment site(s), 2) determine the in vivo protective efficacy of gp47 glycopeptide antibodies, and 3) determine the contribution of the glycoproteome in antibody recognition and protection against E. chaffeensis infection. The gp47 glycan composition, linkage, and attachment site(s) will be determined by gas chromatography and mass spectrometry. The role of a major glycopeptide antibody epitope present in the gp47 in antibody mediated immunity to E. chaffeensis will be determined by in vivo efficacy experiments using a SCID mouse model of E. chaffeensis infection to determine immunity provided by anti-glycopeptide and anti-peptide antibodies. The role of the E. chaffeensis glycoproteome in development of protective antibodies will be determined in a SCID mouse model to evaluate protection provided by polyclonal antibodies produced against native and glycan-altered E. chaffeensis. The proposal aims to further the limited understanding of ehrlichial glycoproteins and their role in immunity to E. chaffeensis. HME is an emerging public health concern, and this research will facilitate rational development of vaccines and therapeutics against the most prevalent life-threatening tick- borne disease in North America.