Molecular Mechanisms Regulating Early Stage Tick Feeding

调节早期蜱摄食的分子机制

• 批准号: 8048929
• 负责人: ALBERT MULENGA
• 金额: $ 17.93万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-13 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8048929
• 关键词: Adult; Amblyomma; Animals; Antibodies; Antibody Formation; Antigens; Arthropod Vectors; Blood; Complementary DNA; Containment; Data; Development; Enzyme-Linked Immunosorbent Assay; Epitopes; Failure; Foundations; Future; Goals; Human; Immune Sera; Immunity; Immunization; Infection; Libraries; Mediating; Methods; Molecular; Nature; Nymph; Oryctolagus cuniculus; Peptides; Phage Display; Physiology; Protein Region; Proteins; Recombinant Proteins; Reporting; Research; Resistance; Saliva; Salivary Glands; Screening procedure; Skin; Staging; Tick Control; Tick Infestations; Tick-Borne Diseases; Ticks; Time; United States; Vaccine Antigen; Validation; Vector-transmitted infectious disease; acaricide; base; cDNA Library; design; design and construction; feeding; immunogenic; immunogenicity; mortality; novel strategies; pathogen; programs; success; transmission process

DESCRIPTION (provided by applicant): In the United States reported human vector-borne diseases are primarily tick-borne. For continued cycling of tick-borne disease pathogens in nature, successful tick feeding is required. Molecular mechanisms that regulate early stage tick feeding are poorly defined. They are critical to understanding the acquisition and transmission of pathogens by ticks, which in turn will be important in designing novel approaches to control ticks and tick- borne diseases. The goal of this proposal is molecular identification and target validation of Amblyomma americanum tick saliva proteins that are injected into the host during the first 48 h of tick feeding. The rationale to focus on this time point is that, it precedes the key facets of tick feeding, blood meal up take and tick borne disease agent transmission. The hypothesis is that tick saliva proteins critical to feeding success and pathogen infection of the host are injected into the host during the first 48 h of feeding and blocking their functions will protect animals against tick feeding and pathogen infection. This hypothesis is based on preliminary experimental evidence that repeated tick infestation of rabbits for 48 h with nymph or adult ticks conferred protective tick immunity as revealed by mortality failure of ticks to attach or remain attached onto host skin. Previous efforts to confer protective tick immunity by immunizing animals with single tick saliva recombinant proteins have produced mixed results. In this research we have proposed a previously unexplored approach, to immunize animals against tick feeding with multi-epitope chimeric tick saliva protein vaccine antigens. The idea is that immunity to these chimeric antigens will mimic protective tick immunity conferred tick saliva protein antigens during repeated infestations. There are 3 specific aims. The first is to clone cDNAs that encode A. americanum tick saliva proteins that are injected into the host during the first 48 h of tick feeding. The second is to validate immunogenicity of putative antigenic peptide regions in tick saliva proteins. Validated immunogenic peptides will represent tick saliva protein regions that mediate tick resistance in repeated tick feeding and will thus represent potential tick vaccine antigens. The third is to validate tick immunity and anamnestic antibody response of immunogenic peptide-cocktail immunized rabbits to tick infestation. The rationale is that if immunization of rabbits with immunogenic peptide-cocktails confers tick immunity that is comparable to that in repeated tick infestation, data from this application will set the foundation to design chimeric tick saliva proteins. PUBLIC HEALTH RELEVANCE: In the United States ticks transmit more vector borne disease agents than any other vector arthropod. Limitations associated with current acaricide based tick control strategies that threaten the future sustainability of containment programs for tick borne illnesses, have necessitated the need for development of alternative tick control strategies. Identification of important tick proteins that regulate tick physiology and facilitate tick feeding is important before alternative tick control methods can be developed.

描述（由申请人提供）：在美国报道的人类媒介传播疾病主要是蜱传播的。为了使蜱传疾病病原体在自然界中持续循环，需要成功的蜱喂养。调节早期蜱摄食的分子机制尚不清楚。它们对于了解蜱虫获取和传播病原体至关重要，而这对于设计控制蜱虫和蜱传疾病的新方法也很重要。该提案的目标是对美洲钝蜱蜱唾液蛋白进行分子鉴定和目标验证，这些蛋白在蜱进食的前 48 小时内注射到宿主体内。关注这个时间点的理由是，它先于蜱虫进食、血粉摄取和蜱传疾病媒介传播的关键方面。假设是，对宿主摄食成功和病原体感染至关重要的蜱唾液蛋白在摄食的前 48 小时内被注射到宿主体内，阻断其功能将保护动物免受蜱摄食和病原体感染。这一假设基于初步实验证据，即用若虫或成虫蜱重复感染兔子 48 小时，可赋予蜱保护性免疫力，如蜱死亡未能附着或保持附着在宿主皮肤上所揭示的那样。先前通过用单一蜱唾液重组蛋白免疫动物来赋予蜱保护性免疫力的努力产生了好坏参半的结果。在这项研究中，我们提出了一种以前未探索过的方法，用多表位嵌合蜱唾液蛋白疫苗抗原对动物进行免疫，使其免受蜱喂养。这个想法是，对这些嵌合抗原的免疫力将模仿在重复感染期间蜱唾液蛋白抗原所赋予的保护性蜱免疫。有3个具体目标。第一个是克隆编码美洲蜱唾液蛋白的 cDNA，这些蛋白在蜱进食的前 48 小时内注射到宿主体内。第二个是验证蜱唾液蛋白中假定的抗原肽区域的免疫原性。经验证的免疫原性肽将代表蜱唾液蛋白区域，其在重复蜱喂养中介导蜱抗性，因此代表潜在的蜱疫苗抗原。第三个是验证免疫原性肽混合物免疫的兔子对蜱虫感染的蜱免疫和记忆抗体反应。其基本原理是，如果用免疫原性肽混合物对兔子进行免疫可以赋予与重复蜱感染相当的蜱免疫力，那么来自该应用的数据将为设计嵌合蜱唾液蛋白奠定基础。 公共卫生相关性：在美国，蜱传播的媒介传播疾病比任何其他媒介节肢动物都多。当前基于杀螨剂的蜱虫控制策略的局限性威胁着蜱传疾病遏制计划未来的可持续性，因此需要开发替代的蜱虫控制策略。在开发替代蜱虫控制方法之前，鉴定调节蜱虫生理学和促进蜱虫进食的重要蜱虫蛋白非常重要。