Cow ultralong CDR3 antibodies targeting HIV gp120

靶向 HIV gp120 的牛超长 CDR3 抗体

• 批准号: 9141521
• 负责人: Vaughn Vasil Smider
• 金额: $ 29.81万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9141521
• 关键词: Amino Acids; Antibodies; Antibody Diversity; Antibody Repertoire; Antibody Response; Antigens; Architecture; Binding; Biochemical; Cattle; Codon Nucleotides; Cysteine; Data; Disulfides; Epitopes; Fab Immunoglobulins; Genetic Engineering; Goals; HIV; HIV Antibodies; HIV Envelope Protein gp120; HIV Infections; HIV vaccine; Human; Immunization; Immunoglobulin Domain; Immunoglobulin G; Immunoglobulin Somatic Hypermutation; Immunoglobulins; Immunology; Lead; Length; Maps; Mediating; Monoclonal Antibodies; Mutagenesis; Mutation; Pattern; Polysaccharides; Positioning Attribute; Property; Serum; Structure; Structure-Activity Relationship; Surface; Surface Immunoglobulins; System; Texas; Trastuzumab; Vaccination; Vaccines; Viral; X-Ray Crystallography; base; complementarity-determining region 3; deep sequencing; design; disulfide bond; humanized antibody; improved; insight; neutralizing antibody; novel; public health relevance; response; structural biology; therapeutic development; tool

 DESCRIPTION (provided by applicant): A key feature of several anti-HIV neutralizing antibodies is the unusually long length of their CDR H3s. Cow antibodies are unique in having ultralong CDR3 regions that can be over 60 amino acids in length and are cysteine-rich. Crystal structures of two different antibody Fab fragments reveal that these CDR3s form a very unusual architecture composed of a long β-strand "stalk" which supports a disulfide rich "knob" that protrudes far from the immunoglobulin surface. Interestingly, different antibodies contain different patterns of disulfides, which result in different knob structures. Deep sequencing reveals extensive diversity in the ultralong CDR3s where a multitude of different disulfides could potentially form within the knob. Analysis of clonally derived sequences suggests that this diversity results from somatic hypermutation of an ultralong germline D region that has a severe codon bias towards mutation to cysteine. Thus, the bovine antibody system may produce an unprecedented repertoire of mega CDR3s that fold into an impressive diversity of minifolds containing combinations of somatically generated disulfides. We have immunized cows using the BG505 gp140 trimer and found that they are capable of making a robust and broadly neutralizing serum antibody response. In this exploratory proposal, we will take advantage of the unusual ultralong cow antibody repertoire to generate new monoclonal antibodies against HIV gp120 with the goal of identifying new neutralizing epitopes on HIV.

 描述（由申请人提供）：几种抗 HIV 中和抗体的一个关键特征是其 CDR H3 的长度异常长，牛抗体的独特之处在于具有长度超过 60 个氨基酸且富含半胱氨酸的超长 CDR3 区域。两种不同抗体 Fab 片段的晶体结构表明，这些 CDR3 形成了一种非常不寻常的结构，由长 β 链“茎”组成，该“茎”支撑着突出的富含二硫键的“旋钮”远离免疫球蛋白表面，不同的抗体含有不同模式的二硫键，这导致不同的旋钮结构。对克隆衍生序列的分析显示，超长 CDR3 具有广泛的多样性，其中可能会形成多种不同的二硫键。表明这种多样性是由超长种系 D 区的体细胞超突变引起的，该区具有严重的半胱氨酸密码子偏倚突变。因此，牛抗体系统可能会产生前所未有的针对大型 CDR3 的库。折叠成包含体细胞生成的二硫化物组合的令人印象深刻的多样性。我们使用 BG505 gp140 三聚体对奶牛进行了免疫，发现它们能够产生强大且广泛中和的血清抗体反应。不寻常的超长牛抗体库，用于产生针对 HIV gp120 的新单克隆抗体，目的是识别 HIV 上的新中和表位。