Identification of new antigens for a plague vaccine

鼠疫疫苗新抗原的鉴定

• 批准号: 8188007
• 负责人: ASHOK K CHOPRA
• 金额: $ 34.43万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8188007
• 关键词: Accounting; Address; Aerosols; Animal Model; Animals; Antibiotic Resistance; Antigens; Apoptotic; Attenuated; Attenuated Live Virus Vaccine; Bacteria; Bacterial Antigens; Binding; Biological Assay; Bubonic Plague; Categories; Cellular Stress; Cessation of life; Clinical; Clinical Trials; Data; Development; Disease; Disease Outbreaks; Dose; Down-Regulation; Drug Formulations; Emerging Communicable Diseases; Environment; Enzymes; Epidemic; Exoribonuclease II; Exoribonucleases; Funding; Gene Deletion; Generations; Genes; Global Warming; Goals; Grant; Human; Immune Sera; Immune response; Immunity; Immunization; Infection; Inflammatory Response; Lesion; Levaquin; Link; Lipid A; Lipoproteins; Mediating; Memory; Microarray Analysis; Modeling; Mus; Myristic Acids; Paper; Pasteurella pseudotuberculosis; Pathogenesis; Peptide Hydrolases; Pigmentation physiologic function; Plague; Plague Vaccine; Plasmids; Plasminogen; Pneumonic Plague; Polyribonucleotide Nucleotidyltransferase; Prevalence; Protease Gene; Proteins; Publications; Publishing; Rattus; Recombinants; Ribonucleases; Rodent; Role; Serum; Signal Pathway; Signal Transduction; Smallpox; Splenocyte; Stress; Subunit Vaccines; Survivors; Systemic infection; Testing; Tissues; Toll-Like Receptor 2; Vaccines; Virulence; Virulent; Western Blotting; Yersinia pestis; attenuation; base; biological adaptation to stress; biothreat; cell envelope; coping; immunogenic; killings; macrophage; mouse model; mutant; novel; pandemic disease; programs; protective effect; resistant strain; response; transmission process; vaccine candidate

DESCRIPTION (provided by applicant): Historically, plague is one of the most devastating epidemic diseases known to mankind (second only to smallpox), resulting overall in more than 200 million deaths related to three recorded plague pandemics. Since Y. pestis has the potential to cause large-scale outbreaks, the WHO has categorized plague as a re-emerging infectious disease, and there is a concern for a possible fourth pandemic because of global warming, resulting in an increased prevalence of plague in rodent hosts. The current relevance of Y. pestis as a bioweapon is due to its high virulence and the development of multi-antibiotic-resistant strains. Although immunization of humans with plague vaccine will discourage the use of Y. pestis as a bioweapon, currently there is no vaccine against plague. During the current funding of the grant, we identified a new antigen (Braun lipoprotein) of Y. pestis that contributed to the development of bubonic and pneumonic plague. Our studies indicated that mice immunized with the mutant strain of Y. pestis deleted for the lpp and pigmentation locus (pgm) genes were protected against developing pneumonic plague caused by the highly virulent Y. pestis CO92 strain. We have now delineated the signaling pathways initiated by Lpp to cause host damage. Most importantly, our data indicated that the lpp mutant was unable to survive within macrophages, which was linked to the down-regulation of a stress response gene (htrA) in this mutant. We inferred from these data that other stress-associated genes (e.g., exoribonucleases) could also be involved in lpp-mediated, attenuated virulence of the bacterium. Indeed, deletion of the gene encoding polynucleotide phosphorylase (PNPase) also attenuated Y. pestis in a mouse model of systemic infection and provided protection against plague. We have proposed 3 specific aims for this grant. Aim 1 is to generate double mutants of Y. pestis CO92 in which genes encoding plasminogen-activating protease (pla), pnp, and two other predominant exoribonucleases (e.g., rnb [RNase II] and rnr [RNAse R]) will be deleted from the lpp gene minus background strain of Y. pestis CO92. These mutants will be tested for their attenuation in bubonic and pneumonic plague models (mice and rats). In aim 2, we will characterize protective immune responses of the most highly attenuated mutant in an animal model and the protection afforded by such a mutant against challenge with the parental CO92 strain. We have identified several immunogenic proteins in the WT CO92 strain that reacted with the immune sera of rats infected with CO92 strain. These antigens may represent excellent candidates for addition in the recombinant plague vaccine. Therefore in aim 3, we will first delete these genes from the WT bacterium to demonstrate their effects on bacterial virulence. Second, we will purify such immunogenic proteins and evaluate their protective effects after immunization of mice and rats followed by subsequent infection with the virulent Y. pestis. Overall, our studies are focused on identifying new live-attenuated vaccine strains of Y. pestis and to characterize the new immuno-protective CO92 antigens that could be important for the recombinant plague vaccine. PUBLIC HEALTH RELEVANCE: Y. pestis is a category A select agent and its potential to be used as a biothreat agent has caused significant concerns. In addition, plague represents a re-emerging infectious disease because of an increased number of cases worldwide. Currently, there is no vaccine available against this deadly disease, and hence our efforts are to develop new and novel countermeasures against plague, as well as to study new mechanisms of pathogenesis in Y. pestis.

描述(申请人提供)：从历史上看，鼠疫是人类已知的最具破坏性的流行病之一(仅次于天花)，总共造成2亿多人死亡，与三次有记录的鼠疫大流行有关。由于鼠疫有可能导致大规模疫情，世界卫生组织已将鼠疫归类为一种重新出现的传染病，人们担心由于全球变暖，可能会发生第四次大流行，导致鼠疫在啮齿动物宿主中的流行增加。目前鼠疫杆菌作为生物武器的相关性是由于它的高毒力和对多重抗生素耐药菌株的发展。尽管给人类接种鼠疫疫苗会阻止使用鼠疫杆菌作为生物武器，但目前还没有针对鼠疫的疫苗。在目前的赠款资金期间，我们确定了一种新的鼠疫杆菌抗原(布劳恩脂蛋白)，它促进了腺鼠疫和肺鼠疫的发展。我们的研究表明，用缺失LPP和PGM基因的鼠疫菌突变株免疫的小鼠，可以抵抗由高毒力鼠疫菌CO92株引起的肺炎鼠疫。我们现在已经描述了LPP启动的导致宿主损害的信号通路。最重要的是，我们的数据表明，LPP突变体不能在巨噬细胞内存活，这与该突变体中的应激反应基因(HtrA)下调有关。我们从这些数据中推断，其他与压力相关的基因(如外切核酸酶)也可能参与LPP介导的、减弱的细菌毒力。事实上，编码多核苷酸磷酸化酶(PNPase)的基因的缺失也可以减弱系统性感染小鼠模型中的鼠疫杆菌，并提供对鼠疫的保护。我们为这笔赠款提出了3个具体目标。目的1建立鼠疫耶尔森氏菌CO92的双突变株，将编码纤溶酶原激活酶(Pla)、PNP和另外两种主要外切核酸酶(如RnB[RNase II]和RnR[RNase R])的基因从LPP基因阴性的鼠疫菌CO92株中删除。这些突变体将在腺鼠疫和肺炎鼠疫模型(小鼠和大鼠)中进行减毒试验。在目标2中，我们将在动物模型中表征最高减毒突变株的保护性免疫反应，以及这种突变株对亲本CO92株的攻击所提供的保护作用。我们在WT CO92株中鉴定了几种免疫原性蛋白，它们与感染CO92株的大鼠的免疫血清发生反应。这些抗原可能是添加到重组鼠疫疫苗中的极佳候选者。因此，在目标3中，我们将首先从WT细菌中删除这些基因，以证明它们对细菌毒力的影响。其次，我们将提纯这些免疫原性蛋白，并评估它们在小鼠和大鼠免疫后随后感染强毒鼠疫菌后的保护效果。总体而言，我们的研究集中在鉴定新的鼠疫减毒活疫苗株，并表征可能对重组鼠疫疫苗重要的新的免疫保护性CO92抗原。 公共卫生相关性：鼠疫耶尔森氏菌是A类选择性制剂，其作为生物制剂的潜力已引起重大关注。此外，鼠疫是一种重新出现的传染病，因为全世界的病例数量都在增加。目前，还没有针对这种致命疾病的疫苗，因此我们的努力是开发新的和新的鼠疫对策，以及研究鼠疫的新致病机制。