PATHOGENESIS OF HAEMOPHILUS DUCREYI INFECTIONS

杜克雷嗜血杆菌感染的发病机制

• 批准号: 2886603
• 负责人: Stanley M. Spinola
• 金额: $ 27.58万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-01-01 至 2001-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2886603
• 关键词: HIV infections; Haemophilus; adhesin; bacterial antigens; bacterial genetics; biopsy; communicable disease transmission; confocal scanning microscopy; cytokine; disease /disorder model; genetic strain; helper T lymphocyte; human tissue; immunocytochemistry; immunoelectron microscopy; membrane proteins; microorganism immunology; model design /development; monoclonal antibody; mutant; pathologic process; pilus; sexually transmitted diseases; virulence

Haemophilus ducreyi is the etiologic agent of chancroid, a genital ulcer disease that facilitates transmission of the Human Immunodeficiency Virus (HIV). Our understanding of the pathogenesis of chancroid, virulence determinants, and immune responses to H.ducreyi has been hampered by a total lack of longitudinally collected clinical specimens from naturally infected patients. H. ducreyi is a strict human pathogen that expresses cell surface components that mimic human antigens. To study the pathogenesis of chancroid, we have developed an experimental model of skin infection in human volunteers. We have refined the model so that the course of experimental infection mimics naturally occurring disease. The focus of this application is to develop and study the model so that we can test hypotheses about pathogenesis, host immune responses and candidate virulence determinants. In the experimental model, papular lesions may either spontaneously resolve or progress to pustule formation. Our data suggests that the outcome of infection is modulated by local factors, and this is the first evidence that the human host can mount an effective immune response to H. ducreyi. The focal point of the immune response is a cutaneous infiltrate of CD4+ cells. Our first hypothesis is that the T Cell infiltrate and cytokines produced in the experimental lesions change over time and influence the outcome of infection in the model. H. ducreyi adheres to human keratinocytes and adheres to and sometimes in vades human fibroblasts in vitro. Our second hypothesis is the H. ducreyi adheres to keratinocytes and to fibroblasts and that some of the bacteria successfully invade eukaryotic cells, allowing the organism to evade host defenses. Bacterial surface structures such as outer membranes proteins (OMPs) and pili have important roles in the pathogenesis of gram negative bacterial infections. Our laboratory has characterized several conserved surface components of H. ducreyi including the major outer membrane protein (MOMP) and pili. Using a genetic approach, we wish to asses the role MOMP and pili in pathogenesis. Our third hypothesis is that the experimental infection model can discriminate between the virulence of the parental strain and isogeneic mutants in candidate virulence determinants. To test these hypotheses, our specific aims include: standardization of the human challenge model of experimental H. ducreyi infection; immunohistopathological and cytokine analysis of experimental lesions biopsied at different times during the course of infection; localization of the bacteria in the lesions; construction of isogeneic mutants in the MOMP, pilus, or a pilus associated adhesion; assessment of the ability of the human challenge model to discriminate between the parental strain and isogeneic mutants in candidate virulence determinants.

嗜血杆菌Ducreyi是牙冠的病因，生殖器溃疡 促进人类免疫缺陷病毒传播的疾病 （艾滋病病毒）。我们对冠状动物，毒力的发病机理的理解 决定因素和对H. ducreyi的免疫反应受到A的阻碍 完全缺乏自然收集的纵向收集的临床标本 感染的患者。 H. ducreyi是一种严格的人类病原体，表达 模拟人类抗原的细胞表面成分。研究 Chancroid的发病机理，我们开发了一个实验模型 人类志愿者的皮肤感染。我们已经完善了模型，以便 实验感染的过程模仿天然发生的疾病。这 该应用的重点是开发和研究模型，以便我们 可以检验有关发病机理，宿主免疫反应和 候选毒力决定因素。 在实验模型中，丘疹病变可能会自发地 解决或进展到脓疱形成。我们的数据表明 感染的结果是由局部因素调节的，这是第一个 证据证明人类宿主可以对 H. Ducreyi。免疫反应的焦点是皮肤 CD4+细胞的浸润。我们的第一个假设是T细胞 实验病变中产生的浸润和细胞因子随着 时间和影响模型中感染的结果。 H. Ducreyi遵守人角质形成细胞并遵守有时 在体外vades人的成纤维细胞。我们的第二个假设是H。 Ducreyi遵守角质形成细胞和成纤维细胞，其中一些 细菌成功侵入真核细胞，使生物体得以 逃避主机防御。 细菌表面结构，例如外膜蛋白（OMP）和 pili在革兰氏阴性细菌的发病机理中具有重要作用 感染。我们的实验室表征了几个保守的表面 H. ducreyi的成分，包括主要的外膜蛋白 （MOMP）和Pili。使用遗传方法，我们希望评估角色MOMP 和发病机理中的菌毛。我们的第三个假设是实验 感染模型可以区分父母的毒力 候选毒力决定因素中的应变和异质突变体。 为了检验这些假设，我们的具体目的包括： 实验性H. ducreyi感染的人类挑战模型； 实验病变的免疫组织病理学和细胞因子分析 在感染过程中在不同时间进行活检；本土化 病变中的细菌；在 MOMP，Pilus或pilus相关的粘附；评估能力 人类挑战模型以区分父母应变 和候选毒力决定因素中的异依性突变体。