Expressing a novel class of heavy chain antibodies

项目总结 -- 重链抗体(HCAbs)是一种罕见的由骆驼表达的免疫球蛋白 还有鲨鱼。它们以同源二聚体的形式出现，其中每个多肽的可变区(V)与配体结合。 不需要传统抗体中的轻链伙伴，HCAb试剂具有 尺寸和分子可操纵性的优势，是药物开发和开发的有前途的工具 免疫疗法。 编码HCAbs的基因在两个亚类的软骨鱼中分别进化，这两个亚类420 百万年前。它们的HCAb和病原体识别能力的作用尚未得到 特征，尽管已经确定HCAb凸起抗原结合位点可以检测到 传统抗体无法获得或绕过的表位。我们发现了新的抗体基因 一种软骨鱼，其组成基因片段已进化为编码和重新排列以表达 配体结合部位的赖氨酸和精氨酸。其主要抗原结合的抗体谱系 环是灵活的，电阳性在脊椎动物中是独一无二的，这为寻找抗原性提供了机会 不同于经典定义的决定因素。 将产生一组转基因小鼠来表达一组嵌合的鱼类基因。这样做的第一个目的是 建议是产生突变的小鼠，第二是测试转基因谱系的能力 对各种免疫原有反应。建议进行HCAb检测新表位的实验 细菌被膜和细胞壁。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.