Human Immune Response to Haemophilus Ducreyi Infection

描述(申请人提供)：杜雷氏嗜血杆菌引起下巴，促进艾滋病毒传播。在人类的实验感染模型中，丘疹在24小时内发育，并溶解或演化为脓疱。脓肿包含由中性粒细胞和巨噬细胞组成的脓肿，而T细胞、髓系树突状细胞(DC)和巨噬细胞在脓肿下方形成疏松的肉芽肿。在失败的脓疱病状态下，杜氏嗜血杆菌被吞噬细胞包围，这些吞噬细胞不会吞噬有机体。虽然一些受试者会形成脓疱疹，但所有感染部位都会在其他受试者身上消退。当脓疱形成者和解决者再次感染时，他们倾向于向最初的结果分离，确认宿主效应。从两次形成脓疱者(PP组)和两次分解者(RR组)的血液中分离出的PMN和巨噬细胞对杜氏杆菌的吞噬能力没有差异，这表明感染部位的环境调节了吞噬功能。在第三次感染PP和RR的受试者中，皮损转录本在两组之间存在差异，证实了他们的局部免疫反应不同。两组的髓系DC对H.ducreyi有共同的转录反应，但每组都有独特的反应。感染的PP DC上调了DC成熟的标志和半成熟或调节性DC的标志，下调了已知促进DC成熟或抗原处理的转录本。感染RR DC仅上调DC成熟转录本。我们的总体假设是，杜氏杆菌与DC的相互作用以及感染DC与T细胞的相互作用是病变有效(RR)或无效(PP)吞噬反应的关键决定因素。来自PP组的DC可能促进失调的1型和Tr反应，导致反吞噬细胞因子环境，而来自RR组的DC促进1型反应，导致亲吞噬环境。为了验证这些假设，我们的具体目标包括：比较RR组和PP组第三次感染48小时后收集的病变组织中的转录本；比较PP组和暴露于活体杜氏杆菌的RR组DC的基因表达和蛋白质组谱；测试与活的杜氏杆菌冲击的DC并与来自RR组的T细胞共培养是否导致类型1反应，而来自PP组的共培养导致类型1和Tr反应；检查由H.ducreyi-DC-T细胞相互作用产生的细胞因子是促进还是抑制生物体的吞噬作用以及吞噬调节的机制。我们将通过对再次感染的PP和RR受试者的活检组织的观察来证实我们的体外结果。 莱昂纳多摘要：杜氏杆菌是一种能引起生殖器溃疡的细菌。当我们用细菌感染人类志愿者的手臂时，一些人会患上疾病，而另一些人则会清除感染。我们试图回答一个重要的问题：为什么一些感染了细菌的人会生病，而另一些人则不会？

DESCRIPTION (provided by applicant): Haemophilus ducreyi causes chancroid, which facilitates HIV transmission. In an experimental infection model in humans, papules develop within 24 h and either resolve or evolve into pustules. Pustules contain an abscess composed of PMNs and macrophages, while T cells, myeloid dendritic cells (DC) and macrophages form a loose granuloma below the abscess. In the failed pustular state, H. ducreyi is surrounded by phagocytes that do not ingest the organism. Although pustules form in some subjects, all infected sites resolve in other subjects. When pustule formers and resolvers are re-infected, they tend to segregate towards their initial outcome, confirming a host effect. PMNs and macrophages isolated from the blood of those who formed pustules twice (PP group) or resolved twice (RR group) did not differ in their ability to ingest H. ducreyi, suggesting that the environment at the site of infection modulates phagocytosis. In PP and RR subjects infected a third time, lesional transcripts differed between the groups, confirming that their local immune responses are different. Myeloid DC from both groups had a common transcript response to H. ducreyi, but each group had unique responses. Infected PP DC upregulated transcripts that were markers of DC maturation and markers of semi-mature or regulatory DC and downregulated transcripts known to promote DC maturation or antigen processing. Infected RR DC only upregulated transcripts of DC maturation. Our overall hypothesis is that the interaction of H. ducreyi with DC, and the interaction of infected DC with T cells are key determinants of effective (RR) or ineffective (PP) phagocytic responses in lesions. DC from the PP group likely promote a dysregulated Type 1 and Tr response that leads to an antiphagocytic cytokine environment, while DC from the RR group promote a Type 1 response that leads to a pro-phagocytic environment. To test these hypotheses, our specific aims include: comparison of transcripts in lesions collected 48 h after a third infection of the RR and PP groups; comparison of the gene expression and proteomic profiles of DC derived from the PP and the RR groups exposed to live H. ducreyi; testing whether DC pulsed with live H. ducreyi and co-cultured with T cells from the RR group result in Type 1 responses while co-cultures derived from the PP group lead to Type 1 and Tr responses; examination of whether the cytokines generated by H. ducreyi - DC - T cell interaction promotes or inhibits phagocytosis of the organism and of the mechanisms underlying the modulation of phagocytosis. We will confirm our in vitro results with observations made on biopsies obtained from PP and RR subjects who are re-infected. Lay summary: H. ducreyi is a germ that causes genital ulcers. When we infect human volunteers on the arm with the germ, some people develop disease while others clear the infection. We seek to answer an important question: Why do some people who become infected with a germ get sick, while others do not?