Characterization of long-circulating phages isolated from in vivo mouse studies

项目摘要 最近噬菌体疗法的复兴导致了许多人类患者的成功案例。 在小鼠和人类中的各种研究表明，噬菌体被迅速清除，这意味着噬菌体可以被清除。 治疗后在患者血液中不能观察到噬菌体。因此，面临的主要挑战之一是， 噬菌体疗法的扩大使用是产生不能迅速清除的噬菌体 病人对此的论据很清楚--感染性噬菌体在体内停留的时间越长， 找到致病菌宿主的机会循环噬菌体的寿命一直是 调查了好几次。这些研究表明，可以分离出循环时间更长的噬菌体。 不幸的是，这些噬菌体的基因组往往没有被测序， 特征，在我们理解这些噬菌体是如何被改变以在环境中生存的过程中留下了空白。 身体延长时间。本建议的目的是了解导致更长时间的 噬菌体在循环系统中的存活。我们的工作旨在提供重要的翻译见解 用于使合成噬菌体能够在患者体内循环更长时间， 噬菌体疗法 我们的中心假设是，增加循环时间是由于氨基酸取代（S）的主要 稳定噬菌体或使噬菌体逃避免疫捕获的衣壳蛋白 细胞一项针对循环时间较长的λ噬菌体的经典研究表明，衣壳中的单个突变 蛋白质负责表型，但这种表型的机制尚未研究。我们 我建议把重点放在噬菌体P22和Sf6上，以了解这些噬菌体体内稳定的机制。 两种不同但易于处理且特征良好的噬菌体，具有以下特定目的： 目的1）假设：主要衣壳蛋白中的氨基酸取代增加了循环时间。 目的1a）分离和表征具有增强的循环时间的噬菌体。 目的1b）确定导致循环时间增加的突变残基是否是一个可推广的特征。 目的2）假设：长循环突变噬菌体不被巨噬细胞降解。

PROJECT SUMMARY The recent renaissance in bacteriophage therapy has led to a number of successful cases in human patients. Various studies in mice and humans have shown that bacteriophages are rapidly cleared, meaning the bacteriophages cannot be observed in patient blood after the treatment. Thus, one of the main challenges facing the expanded use of bacteriophage therapy is the creation of bacteriophages that are not cleared rapidly from the patient. The argument for this is clear -- the longer infectious bacteriophages can stay in the body, the greater their chance of finding their pathogenic bacteria host. The longevity of circulating bacteriophages has been investigated several times. These studies showed that longer circulating bacteriophages can be isolated. Unfortunately, often the genomes of these bacteriophages were not sequenced nor were the bacteriophages characterized, leaving a gap in our understanding of how these bacteriophages were altered to survive in the body for extended times. The objective of this proposal is to understand the mechanisms leading to longer bacteriophage survival in the circulatory system. Our work is designed to provide important translational insights for making synthetic bacteriophages able to circulate longer inside patients and thereby increasing the efficacy of bacteriophage therapy. Our central hypothesis is that enhanced circulation times are due to amino acid substitution(s) in the major capsid protein that either stabilize the bacteriophage or allow the bacteriophage to evade capture by immune cells. A classic study of longer-circulating lambda bacteriophages revealed that a single mutation in the capsid protein was responsible for the phenotype, but the mechanism for this phenotype was not investigated. We propose to focus on bacteriophages P22 and Sf6 to understand the mechanism for in vivo stabilization in these two different but tractable and well-characterized bacteriophages, with the following specific aims: Aim 1) Hypothesis: the circulation time is increased by amino acid substitutions in the major capsid protein. Aim1a) Isolate and characterize bacteriophages with enhanced circulation times. Aim1b) Determine if the mutated residues resulting in increased circulation time is a generalizable feature. Aim 2) Hypothesis: the long circulating mutant bacteriophages are not degraded by macrophages.