Polyclonal human antibody in cloned HAC-transgenic cows

说明(申请人提供)：肠毒素被认为是一种可能的生物恐怖主义威胁，因为它的致命性和持久性。葡萄球菌和链球菌肠毒素包括一组称为热原毒素超抗原的毒素。暴露在高剂量的这些超级抗原下可能是致命的，而暴露在低剂量下不是致命的，但可能会相当虚弱。有人认为，肉毒杆菌毒素SEB是战场上最重要的两种毒素威胁。接触SEB被认为是主要的风险，因为SEB具有潜在的致命性，以及SEB对接触者的丧失能力的影响。过去，有几个国家实施了生物武器计划，产生了大量的肠道毒素细菌。目前还没有针对这些毒素的大规模疫苗接种计划。在缺乏疫苗的情况下，建议对接触细菌肠毒素的人进行静脉免疫球蛋白(IVIG)被动免疫，但由于缺乏大量可识别的此类个人，因此这种方法不切实际。 这项建议是为了开发一个大型动物系统来生产抗肠毒素多肽的人多克隆抗体。已有研究表明，携带人工人类染色体(HAC)的转基因小鼠在受到抗原攻击时能产生所有类别的人类抗体，并且具有广泛的谱系。在目前的工作中，类似的策略将应用于牛，那里的抗体产量将远远高于老鼠。我们已经证明，我们可以创造出具有包含人类免疫球蛋白基因的HAC的牛克隆，而且染色体是稳定的，并且在胎儿发育到新生儿生命的整个过程中都有表达。对正常和克隆转基因小牛对肠毒素的免疫反应进行了研究。 这种解决人类IVIG供应有限的新颖而实用的解决方案有几个优点。首先，它将能够以合理的成本生产大量的人类抗体。其次，它将在设计免疫策略方面提供更大的灵活性，以产生高滴度、高特异性的抗体，这是人类志愿者所不能做到的。第三，它将为生产临床上重要的针对其他细菌和病毒病原体的人类抗体试剂提供一种新的使能技术。

DESCRIPTION (provided by applicant): Enterotoxins are considered a possible bioterrorism threat because of its lethality and its durability. Staphylococcal and streptococcal enterotoxins include a group of toxins known as pyrogenic toxin superantigens. Exposure to a high dose of these superantigens can be fatal while exposure to lower doses is not fatal but can be quite debilitating. It has been suggested that botulinum toxin SEB are the two most important toxin threats on the battlefield. Exposure to SEB is thought to be major risk because of potential lethality as well the incapacitating effects SEB has on exposed individuals. Several nations have had bioweapons programs in the past that produced large quantities of enterotoxin bacteria. No mass vaccination program is envisioned for these toxins. In the absence of a vaccine, passive immunization with intravenous immunoglobulin (IVIG) of people exposed to bacterial enterotoxins has been suggested however the lack of a large and identifiable pool of such individuals makes this approach impractical. This proposal is to develop a large animal system for producing human polyclonal antibody against an enterotoxin peptide. It has been shown that transgenic mice carrying a artificial human chromosome (HAC) produce human antibody of all classes and with a broad repertoire when challenged with antigen. In the current work, a similar strategy will be applied to cattle, where the yield of antibody would be far greater than with mice. We have already shown that we can create cattle clones that have a HAC containing the human Ig genes, and that the chromosome is stable and is expressed throughout fetal development into neonatal life. Work is proposed to characterize the immune response to enterotoxin in normal and in cloned transgenic calves. This novel and practical solution to the limited supply of human IVIG has several advantages. First, it would enable the production of large quantities of human antibody at a reasonable cost. Second, it would provide greater flexibility in designing immunization strategies for producing high titer; high specificity antibody beyond what is possible with human volunteers. Third, it would provide a new enabling technology for producing clinically important human antibody reagents against other bacterial and viral pathogens.