DEVELOPMENT OF A RECOMBINANT VACCINE FOR RICIN TOXIN

描述（由申请人提供）：蓖麻毒素是已知最强的生物毒素之一，过去曾被用作生物武器。最近，由于在2003年期间几起广为宣传的事件中发现并记录了蓖麻毒素的痕迹，人们对实际使用蓖麻毒素的潜在威胁给予了很大关注。目前，还没有获得许可的疫苗来防止蓖麻毒素在潜在的恐怖袭击中或在战场上作为武器使用的可能性。本拟议项目的目的是通过生产工艺和中间放大阶段开发一种肌肉注射蓖麻毒素疫苗，直至并包括在小瓶中配制佐剂，用于人体临床研究的最终放行。该项目的团队包括来自行业的代表（DOR Biopharmaceuticals，Inc. [DOR]和Cambrex Biosciences，Inc. [CAMB]）、美国德克萨斯大学西南医学中心[UTSWMC]和堪萨斯[英国]）以及一个非营利研究组织（斯坦福大学研究所[SRI]）。除了未来的I/II期临床试验外，预计至少有数千人剂量的生产目标足以进行稳定性和毒性试验。候选疫苗是一种重组多肽，来源于在大肠杆菌中产生的蓖麻毒素A链。coli宿主菌。拟议的努力将集中在开发一个以前的特点，基因灭活蓖麻毒素A链，含有非冗余的结构突变的网站，导致损失的毒性。执行特定目标所涉及的活动将包括E.大肠杆菌，提高工艺产率，开发和验证工艺方法，测定和稳定性指示试验。在配制用于临床使用的疫苗时，将解决有助于抗原在溶液中稳定性的几个因素。此外，将在动物模型中测试开发的批次的有效性，并解决潜在的毒性问题。对抗蓖麻毒素中毒的疫苗开发中的一个关键问题是动物保护性反应与人类保护性反应的相关性，因为在开发期间无法进行人类攻击/功效研究。根据初步数据，这种特定的疫苗抗原在某些条件下聚集，可能影响效力和稳定性。疫苗储存期间多肽结构的保存也将通过在蛋白质稳定化受体中配制疫苗候选物来解决。

DESCRIPTION (provided by applicant): Ricin is one of the most potent biological toxins known and has been used as a biological weapon in the past. Much attention has been recently focused on the potential threat of actual ricin use, since traces of ricin have been found and documented in several well publicized incidents during 2003. Currently, there is no licensed vaccine to protect against the possibility of the aerosol use of ricin in a potential terrorist attack or as a weapon on the battlefield. The purpose of this proposed project is to develop an intramuscularly administered ricin vaccine through process and intermediate scale-up stages of manufacturing, up to and including formulation with adjuvant in vials for final release for human clinical studies. The team for this project includes representatives from industry (DOR Biopharmaceuticals, Inc. [DOR] and Cambrex Biosciences, Inc. [CAMB]), academe (University of Texas Southwestern Medical Center [UTSWMC] and the University of Kansas [UK]) and a non-profit research organization (Stanford Research Institute [SRI]). A production goal of at least several thousand human doses sufficient for stability and toxicity testing, in addition to future Phase I/II clinical testing, is projected. The vaccine candidate is a recombinant polypeptide derived from the A chain of ricin toxin produced in an E. coli host strain. The proposed efforts will focus on the development of a previously characterized genetically inactivated ricin A chain that contains non-redundant structural mutations in sites resulting in loss of toxicity. The activities involved in executing the specific aims will include maximization of expression levels in E. coli, improvement of process yields, and development and validation of process methods, assays, and stability-indicating tests. Several factors that contribute to the stability of the antigen in solution will be addressed in formulating the vaccine for clinical use. Further, the developed lots will be tested in animal models for efficacy and potential toxicity issues will be addressed. A key issue in the development of a vaccine to combat ricin intoxication will be the correlation of animal protective responses with human protective responses, since no human challenge/efficacy studies can be performed during development. Based on preliminary data, this particular vaccine antigen aggregates under certain conditions, potentially affecting potency and stability. Preservation of the polypeptide structure during storage of the vaccine will also be addressed by formulating the vaccine candidate in protein stabilizinq recipients.