Polyclonal human antibody in cloned HAC-transgenic cows

描述（由申请方提供）：肠毒素因其致命性和持久性而被视为可能的生物恐怖主义威胁。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。暴露于高剂量的这些超抗原可能是致命的，而暴露于较低剂量不是致命的，但可能是相当衰弱的。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。暴露于SEB被认为是主要风险，因为潜在的致命性以及SEB对暴露个体的失能作用。一些国家过去曾有过生产大量肠毒素细菌的生物武器计划。没有针对这些毒素的大规模疫苗接种计划。在没有疫苗的情况下，已经建议对暴露于细菌肠毒素的人进行静脉内免疫球蛋白（IVIG）的被动免疫，但是缺乏大量可识别的此类个体库使得这种方法不切实际。 本研究旨在建立一个大规模的动物系统，用于生产抗肠毒素肽的人多克隆抗体。已经表明，携带人工人染色体（HAC）的转基因小鼠在用抗原攻击时产生所有类别的人抗体并且具有广泛的库。在目前的工作中，类似的策略将应用于牛，其中抗体的产量将远远高于小鼠。我们已经证明，我们可以创建具有包含人类IG基因的HAC的牛克隆，并且染色体是稳定的，并且在整个胎儿发育到新生儿生命中表达。工作提出了肠毒素在正常和克隆的转基因小牛的免疫反应的特点。 这种新颖而实用的解决人类IVIG有限供应的方案具有几个优点。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，以产生超出人类志愿者可能的高滴度、高特异性抗体。第三，它将提供一种新的使能技术，用于生产针对其他细菌和病毒病原体的临床重要人类抗体试剂。

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.