Molecular and Structural Studies of Antibody Diversity Mechanisms

摘要 抗体分子作为治疗和诊断分子非常重要。更多 最近，独特的支架，如骆驼的VHH，甚至非抗体框架，如 “打结”在生物医学中已经变得很重要。日本血吸虫病患者抗体多样性和抗原结合 哺乳动物通常局限于免疫球蛋白折叠的CDR环。在实验中 挑战这一范式，我们最近解决了两个牛的晶体结构 含有超长CDR H3s(56和61个氨基酸)的抗体，并进行了深度测序 超长曲目。我们的数据显示，这些CDR H3形成了一种非常不寻常的结构 由一个长长的b链“柄”组成，它支撑着一个富含二硫化物的“旋钮”，这个旋钮伸出很远 从免疫球蛋白表面。有趣的是，这两种不同的抗体含有不同的 二硫化物的图案，这导致了不同的旋钮结构。深度测序揭示了 超长CDR H3s的广泛多样性，其中多种不同的二硫化物可能 可能在旋钮内形成。因此，牛抗体系统可以产生一种 史无前例的巨型CDR H3曲目，可能会带来令人印象深刻的多样性 含有身体产生的二硫化物组合的迷你花朵。因此，抗体的多样性 位于一个由免疫球蛋白结构域支持的新的迷你结构中。我们将表演 结构、功能和工程研究以研究这种新抗体的特性 班级，并带头将这种独特的结构发展成治疗学。

Abstract Antibody molecules are enormously important as therapeutic and diagnostic molecules. More recently, unique scaffolds like the VHH of camelids, or even non-antibody frameworks like "knottins" have become important in biomedicine. Antibody diversity and antigen binding in mammals is often restricted to the CDR loops of the immunoglobulin fold. In experiments challenging this paradigm, we have recently solved the crystal structures of two bovine antibodies containing ultralong CDR H3s (56 and 61 amino acids) and also deep sequenced the ultralong repertoire. Our data reveal that these CDR H3s form a very unusual architecture composed of a long b-strand "stalk" which supports a disulfide rich "knob" that protrudes far from the immunoglobulin surface. Interestingly, the two different antibodies contain different patterns of disulfides, which result in different knob structures. Deep sequencing reveals extensive diversity in the ultralong CDR H3s where a multitude of different disulfides could potentially form within the knob. Thus, the bovine antibody system can produce an unprecedented repertoire of mega CDR H3s that may result in an impressive diversity of minifolds containing combinations of somatically generated disulfides. Thus, antibody diversity is located in a new minifold supported by the immunoglobulin domain. We will perform structural, functional, and engineering studies to investigate the properties of this new antibody class, as well as to lead the way to developing this unique structure into therapeutics.