Expressing a novel class of heavy chain antibodies

项目摘要 重链抗体（HCAbs）是骆驼科动物表达的一种罕见的免疫球蛋白 还有鲨鱼它们以同源二聚体形式存在，其中每个多肽的可变（V）结构域结合配体。 不需要常规抗体中的轻链配偶体，HCAb试剂具有 尺寸和分子可操作性的优势，并且是药物开发的有前途的工具， 免疫疗法 编码HCAbs的基因在软骨鱼的两个亚类中分别进化， 百万年前他们的HCAbs和病原体识别能力的作用还没有被证实。 表征，尽管已经确定HCAb凸抗原结合位点可以检测 表位不能被常规抗体接近或绕过。我们已经发现了新的抗体基因， 一种软骨鱼，其组成基因片段已经进化到编码并重新排列以表达 在配体结合位点的赖氨酸和赖氨酸。一种抗体库，其主要抗原结合 环是灵活的，并且是脊椎动物中唯一的正电性，这为寻找抗原提供了机会。 与传统定义不同的决定因素。 将产生转基因小鼠以表达一组嵌合鱼基因。第一个目标是 第一个建议是产生突变小鼠，第二个是测试转基因库的能力， 对各种免疫原有反应。提出实验来测试HCAb检测中的新表位。 细菌荚膜和细胞壁。未来的研究将确定它们对疾病的保护作用。

PROJECT SUMMARY   Heavy chain antibodies (HCAbs) are an unusual species of immunoglobulins expressed by camelids and sharks. They occur as homodimers in which the variable (V) domain of each polypeptide binds ligand. Without the requirement for the light chain partner in conventional antibodies, HCAb reagents have the advantage of size and molecular manipulability and are promising tools for drug development and immunotherapy. Genes encoding HCAbs evolved separately in two subclasses of cartilaginous fish that diverged 420 million years ago. The role of their HCAbs and pathogen recognition capabilities have not been characterized, although it has been determined that HCAb convex antigen-combining sites can detect epitopes inaccessible or bypassed by conventional antibodies. We have discovered novel antibody genes in a cartilaginous fish whose component gene segments have evolved to encode and rearrange to express lysines and arginines at the ligand-binding sites. An antibody repertoire whose major antigen-combining loop is flexible and electropositive is unique among vertebrates, presenting an opportunity to seek antigenic determinants different from what has been classically defined. Transgenic mice will be generated to express a set of chimeric fish genes. The first aim of this proposal is to generate the mutant mice, the second is to test the ability of the transgene repertoire to respond to various immunogens. Experiments are proposed to test for HCAb detection of novel epitopes in bacterial capsule and cell wall. Future studies will ascertain their protectiveness against disease.