Immunochemotherapy in Visceral Leishmaniasis

这项转化研究的目标是优化内脏利什曼病（VL）患者的治疗。在VL中，寄生虫在组织巨噬细胞内靶向、失活和复制。除非巨噬细胞激活宿主免疫机制或给予化疗，否则复制不会停止，寄生虫也不会被杀死。因此，达到优化治疗目标的一个合理途径是将激活的宿主机制与化疗相结合。该项目的目标是推动这一战略的应用，以扩大和加速对药物的初步反应，并产生持久的治疗后效果，以防止复发。VL是免疫化疗及其测试的理想候选者，因为在这种感染中：（a）没有疫苗，使得药物治疗成为临床管理的主要手段，（B）可用的化学疗法不是最佳的，（c）对激活或灭活抗性的机制的实验理解是可靠的，并且可以建立在其基础上，（d）候选宿主机制可以在体内模型中鉴定，和（e）这些机制的实验性调整在已建立的内脏感染中是可行的和治疗性的。尽管如此，我们在VL靶向的特定宿主机制以及如何最好地翻译免疫化疗方面的知识存在差距。在杜氏利什曼原虫（Ld）内脏感染模型中提出的工作结果将填补这些空白，为未来采用化疗的干预措施奠定基础。为了实现特定目标，研究计划是实用的-测试体内反应，在已建立的感染中的作用和相关组织病灶中的假设，其中寄生的巨噬细胞，流入的单核细胞和T细胞以及上调和下调免疫炎症机制都与药物相交。目的1：确定化疗是如何转化为杀利什曼原虫的。目的1探讨未经测试的Th 1型机制，可能支配组装的组织肉芽肿内的药物反应。方法集中在单核细胞招募潜在的治疗趋化因子，GM-CSF诱导的血液单核细胞流入和肉芽肿重塑，以及可能改变药物药理学的影响寄生的巨噬细胞。目标2：通过同时靶向一种以上的宿主机制来最大限度地提高化疗的疗效。目标2的计划将通过重新平衡激活/失活机制来放大/加速对药物治疗的反应，并通过靶向两种免疫途径来提高疗效。方法检测Ld诱导的Toll样受体反应、下游MAPK信号通路（p38、ERK 1/2）和基于IL-10的失活细胞因子网络（IL-6、TGF-β 1、IL-27）。

The goal of this translational research is to optimize treatment in patients with visceral leishmaniasis (VL). In VL, parasites target, deactivate and replicate within tissue macrophages. Replication does not cease nor are parasites killed unless macrophage-activating host immune mechanisms supervene or chemotherapy is given. A logical route to the goal of optimizing treatment, then, is combining activated host mechanisms with chemotherapy. This project's objective is to advance the application of this strategy to amplify and accelerate the initial response to drug and produce long-lasting post-treatment effects to prevent relapse. VL is an ideal candidate for immunochemotherapy and its testing, since in this infection: (a) there is no vaccine, making drug therapy the mainstay of clinical management, (b) available chemotherapy is not optimal, (c) experimental understanding of mechanisms which activate or deactivate resistance is solid and ready to be built upon, (d) candidate host mechanisms can be identified in an in vivo model, and (e) experimental adjustment of these mechanisms is both feasible and therapeutic in established visceral infection. Nonetheless, gaps exist in our knowledege of specific host mechanisms to target in VL and in how to best translate immunochemotherapy. Results of the work proposed here in a model of Leishmania donovani (Ld) visceral infection will fill in these gaps, laying the groundwork for future interventions to employ with chemotherapy. To accomplish the Specific Aims, the Research Plan is practical -- testing responses in vivo, effects in established infection and hypotheses in relevant tissue foci where parasitized macrophages, influxing monocytes and T cells, and up- and downregulating immunoinflammatory mechanisms all intersect with drug. Aim 1: Determine how chemotherapy is converted to leishmanicidal. Aim 1 examines untested Th1-type mechanisms which likely govern responses to drug within the assembled tissue granuloma. Methods focus on mononuclear cell recruitment by potentially therapeutic chemokines, GM-CSF-induced blood monocyte influx and granuloma remodeling, and effects which may alter drug pharmacology in parasitized macrophages. Aim 2: Maximize chemotherapy's efficacy by simultaneously targeting more than one host mechanism. Aim 2's plan will amplify/accelerate responsiveness to drug therapy by rebalancing activating/deactivating mechanisms and boosting efficacy by targeting two immunologic pathways. Methods test Toll-like receptor responses, downstream MAPK signaling (p38, ERK1/2) and the IL-10-based deactivating cytokine network (IL-6, TGF-, IL-27) induced by Ld.