Department of Microbiology and Immunology, University of South Alabama Mobile, AL, USA.
Front Cell Infect Microbiol. 2012 Nov 27;2:148. doi: 10.3389/fcimb.2012.00148. eCollection 2012.
Burkholderia mallei the etiologic agent of glanders, causes severe disease in humans and animals and is a potential agent of biological warfare and terrorism. Diagnosis and treatment of glanders can be challenging, and in the absence of chemotherapeutic intervention, acute human disease is invariably fatal. At present, there are no human or veterinary vaccines available for immunization against disease. One of the goals of our research, therefore, is to identify and characterize protective antigens expressed by B. mallei and use them to develop efficacious glanders vaccine candidates. Previous studies have demonstrated that the O-polysaccharide (OPS) expressed by B. mallei is both a virulence factor and a protective antigen. Recently, we demonstrated that Burkholderia thailandensis, a closely related but non-pathogenic species, can be genetically manipulated to express OPS antigens that are recognized by B. mallei OPS-specific monoclonal antibodies (mAbs). As a result, these antigens have become important components of the various OPS-based subunit vaccines that we are currently developing in our laboratory. In this study, we describe a method for isolating B. mallei-like OPS antigens from B. thailandensis oacA mutants. Utilizing these purified OPS antigens, we also describe a simple procedure for coupling the polysaccharides to protein carriers such as cationized bovine serum albumin, diphtheria toxin mutant CRM197 and cholera toxin B subunit. Additionally, we demonstrate that high titer IgG responses against purified B. mallei LPS can be generated by immunizing mice with the resulting constructs. Collectively, these approaches provide a rational starting point for the development of novel OPS-based glycoconjugates for immunization against glanders.
鼻疽伯克霍尔德菌是马鼻疽的病原体，可引起人和动物的严重疾病，是生物战剂和生物恐怖主义的潜在制剂。鼻疽的诊断和治疗具有挑战性，并且在没有化疗干预的情况下，急性人类疾病总是致命的。目前，尚无用于预防疾病的人类或兽医疫苗。因此，我们研究的目标之一是鉴定和表征鼻疽伯克霍尔德菌表达的保护性抗原，并利用它们开发有效的马鼻疽疫苗候选物。先前的研究表明，鼻疽伯克霍尔德菌表达的 O-多糖 (OPS) 既是毒力因子又是保护性抗原。最近，我们证明了与鼻疽伯克霍尔德菌密切相关但非致病性的泰国伯克霍尔德菌可以通过遗传操作来表达 OPS 抗原，这些抗原可被鼻疽 OPS 特异性单克隆抗体 (mAb) 识别。因此，这些抗原已成为我们目前在实验室中开发的各种基于 OPS 的亚单位疫苗的重要组成部分。在这项研究中，我们描述了从泰国伯克霍尔德菌 oacA 突变体中分离鼻疽样 OPS 抗原的方法。利用这些纯化的 OPS 抗原，我们还描述了一种将多糖偶联到蛋白载体（如阳离子化牛血清白蛋白、白喉毒素突变体 CRM197 和霍乱毒素 B 亚基）上的简单程序。此外，我们证明用由此产生的构建体免疫小鼠可以产生针对纯化的鼻疽 LPS 的高滴度 IgG 反应。总之，这些方法为开发用于预防马鼻疽的新型 OPS 糖缀合物提供了合理的起点。
