HUMAN ANTIBODIES FOR THERAPEUTIC INTERVENTION OF SEB EXPOSURE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 该研究计划涉及体内能够中和葡萄球菌肠毒素B(SEB)的抗体的临床前开发。这项建议的最终目标是开发人类抗SEB单抗(HASM)。 到目前为止，我们已经完成了MORAb-048(候选治疗性抗体)在恒河猴体内的完整药代动力学研究。我们还对恒河猴的SEB毒素进行了初步的治疗评估。实验治疗剂(MORAb-048)静脉或肌肉注射，在预先选择的12个时间点抽血。研究结果表明，静脉注射MORAb-048的血浆水平迅速上升，而静脉注射MORAb-048的峰值水平是暴露后48小时。利用这些数据，我们对14只恒河猴(n=14)进行了治疗，要么是48小时(IM)，要么是在气雾剂暴露于SEB毒素之前(-30分钟)。气雾剂暴露的结果表明，尽管所提供的暴露浓度与致死剂量(1LD50)一致，但挑战未能影响大多数未经处理的对照组(n=4，3/4；75%的存活率)。对挑战材料的进一步分析表明，肠毒素纯化过程中关键氨基酸链的丢失限制了试剂的毒性潜力。因此，对SEB的气雾剂挑战不足以测试被测治疗药物(MORAb-048)的保护能力。这项研究正在用挑战材料重复进行，这些挑战材料已经通过蛋白质印迹分析得到保证纯化，以确认SEB试剂的完全结构完整性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This research plan relates to the preclinical development of antibodies capable of neutralizing staphylococcal enterotoxin B (SEB) in vivo. The ultimate objective of this proposal is the development of Human Anti-SEB MAbs (HASMs). Thus far, we have completed a full pharmacokinetics study with MORAb-048 (the candidate therapeutic antibody) in rhesus macaques. We have also performed a preliminary therapeutics evaluation against SEB toxin in rhesus macaques. The experimental therapeutic (MORAb-048) was administered either intravenously or intramuscularly and blood was drawn at 12 preselected time points. Results of the study show a rapid increase in plasma levels in IV-administered MORAb-048, whereas peak levels for IM administration are 48 hours postexposure. Using these data, we administered the therapeutic to rhesus macaques (n=14) either 48 hours (IM) or immediately before (-30 min) aerosol exposure to SEB toxin. Results of the aerosol exposure showed that, although the exposure concentration provided was congruent with a lethal dose (1 LD50), the challenge failed to effect the majority of the untreated controls (n=4, 3/4; 75% survival). Further analysis of the challenge material indicated that the loss of critical amino acid chains during the enterotoxin purification process limited the toxic potential of the reagent. As a result, the aerosol challenge with SEB was not adequate to test the protective capacity of the therapeutic under testing (MORAb-048). This study is being repeated with challenge material that has been assurance-purified using Western blot analysis to confirm the complete structural integrity of the SEB reagent.