Adjunct antibody therapy for severe antibiotic-resistant Acinetobacter baumannii infections

与英国和其他西方国家不同，鲍曼不动杆菌是亚洲国家肺炎和其他感染的常见原因。不幸的是，鲍曼不动杆菌经常引起严重感染，并且经常对抗生素，包括青霉烯类和超广谱青霉素产生高度耐药性，因此鲍曼不动杆菌感染死亡率高，需要大量的医院资源。我们将研究与鲍曼不动杆菌表面结合的抗体是否可以用作与抗生素一起为鲍曼不动杆菌感染患者提供额外治疗的方式。我们将寻找几种蛋白质靶点用于抗体疗法，这种抗体疗法可以增加人类白细胞对鲍曼不动杆菌的杀伤力，或者通过抑制抗生素耐药性的机制使以前无效的抗生素能够杀死鲍曼不动杆菌。为此，我们将：目标1和2。使用我们最近获得的关于300株泰国鲍曼不动杆菌基因含量的信息来识别大多数菌株中存在的蛋白质，并利用这些信息来构建所谓的反基因组阵列。反基因组阵列允许识别引起抗体反应的所有蛋白质，我们将使用鲍曼弧菌保守的蛋白质反基因组阵列来识别哪些蛋白质可以在人或鼠感染鲍曼不动杆菌后引起抗体反应。目的3.使用一种名为RNAseq的技术来鉴定细菌在感染期间或对抗生素的反应中富含哪些鲍曼不动杆菌蛋白质，以了解哪些基因在感染期间或细菌受到抗生素压力时高表达；这些基因应该是抗体治疗的特别好的候选基因。目的4.使用在AIMS 1到3中获得的数据来识别哪些鲍曼不动杆菌蛋白应该作为抗体治疗的潜在靶点进行进一步的研究。我们将制作每一种蛋白的抗原，并获得针对该蛋白的兔抗体，以测试抗体识别和杀死不同鲍曼不动杆菌菌株的能力，方法是通过实验室免疫功能测试和小鼠感染模型。从这些数据中，我们选择了一些蛋白质抗原用于保护性多价抗体疗法，这种抗体疗法针对几种重要的蛋白质，而不仅仅是针对单个蛋白质抗原，因为针对几种蛋白质应该会使治疗作为一种治疗更有效。目的5.为了确定哪些患者患有鲍曼不动杆菌感染，以及这些患者在感染期间何时可以从抗体治疗中受益，我们收集了100名泰国确诊的鲍曼不动杆菌感染患者的数据。此外，我们将提纯这些患者中因鲍曼不动杆菌感染而产生的抗体，用于我们的血液感染模型，以证实抗体治疗可以抑制鲍曼不动杆菌在血液中的生长或对抗生素的耐药性。总体而言，该项目将确定哪些鲍曼不动杆菌蛋白将成为抗体治疗的良好靶点，并确认这种方法在泰国和其他亚洲国家治疗耐药鲍曼不动杆菌感染的潜力。通过允许研究细菌感染的经验丰富的研究科学家也开始研究鲍曼不动杆菌，该项目还将增加研究如何在英国和泰国对抗耐药细菌的研究人员的数量。

Unlike in the UK and other Western countries, the bacteria Acinetobacter baumannii is a common cause of pneumonia and other infections in Asian countries. Unfortunately A. baumannii both often causes severe infections and is frequently highly resistant to antibiotics, including penems and extended spectrum penicillins, and A. baumannii infections therefore have a high mortality and require considerable hospital resources. We will investigate whether antibodies that bind to the surface of A. baumannii bacteria could be used as way of providing additional treatment to patients with an A. baumannii infection along with antibiotics. We will look for several protein targets for an antibody therapy that can increase killing of A. baumannii by human white cells or which by inhibiting mechanisms of antibiotic resistance makes a previously ineffective antibiotic able to kill A. baumannii. To do so we will:Aims 1 and 2. Use information that we have recently obtained on the gene content of 300 Thai A. baumannii strains to identify proteins present in most strains, and use these to construct what is called an antigenome array. Antigenome arrays allow all the proteins that cause an antibody response to be identified, and we will use the A. baumannii conserved protein antigenome array to identify which proteins can cause an antibody response after human or mouse A. baumannii infections.Aims 3. Identify which A. baumannii proteins are abundant on the bacteria during infection or in response to antibiotics using a technology called RNAseq to see which genes are highly expressed during infection or when the bacteria has been stressed by antibiotics; these genes should b particularly good candidates for an antibody therapy.Aim 4. Use the data obtained in aims 1 to 3 to identify which A. baumannii proteins should be investigated further as potential targets for an antibody therapy. We will make each protein antigen and obtain rabbit antibodies to the protein to test the ability of the antibody to recognise and kill different A. baumannii strains using laboratory assays of immune function and mouse models of infection. From these data we select a few protein antigens for use in a protective multivalent antibody therapy that targets several important proteins rather than just individual protein antigens as targeting several proteins should make the treatment more effective as a therapy.Aim 5. To identify which patients with A. baumannii infection and when during infection those patients could benefit from an antibody therapy we will collect data on 100 Thai patients with proven A. baumannii infection. In addition we will purify antibodies developing in these patients as a result of the A. baumannii infection for use in our blood infection model to confirm that antibody therapy can inhibit A. baumannni growth in the blood or resistance to antibiotics. Overall the project will identify which A. baumannii proteins would make good targets for an antibody therapy and confirm the potential of this approach for treating antibiotic resistant A. baumannii infections in Thailand and other Asian countries. By allowing experienced research scientists who work on bacterial infections to start investigating A. baumanii as well, the project will also increase the number of researchers investigating how to combat antibiotic resistant bacteria both in the UK and in Thailand.