Engineered Bovine Antibodies in the Development of Novel Therapeutics, Immunomodulators and Vaccines

Abstract

Some bovine antibodies across all classes are unique, such as the CDR3 of the variable heavy-domain (VH CDR3), which is exceptionally long (up to 66 amino acids), unlike most conventional antibodies where the VH CDR3 loops range from 10 to 25 amino acids. The exceptionally long VH CDR3 is encoded by unusually long germline IGHD genes together with insertion of novel "a" nucleotide rich conserved short nucleotide sequence (CSNS) specifically at the IGH V-D junction. Such an exceptionally long VH CDR3 confers unique "knob and stalk" structural architecture where the knob, formed by intra-VH CDR3 disulfide bridges, is separated by 20 Å solvent exposed stalk composed of anti-parallel beta strands. The substitution of the knob with cytokines, such as, erythropoietin and granulocyte colony stimulating factor 3 (granulocyte colony stimulating factor), results in expression of functional fusion proteins with enhanced pharmacokinetics. The beta stranded stalk can be substituted with other rigid structures, for example, repeat alpha helices to form coiled-coil that mimics the beta-stranded stalk and, thus, opens opportunities for insertion of this structure in the CDRs of antibodies across species. Given the versatility of such a structural platform in bovine antibody VH CDR3, it provides the opportunity for the development of new generation of diagnostics, therapeutics, vaccines and immunomodulating drugs. OPEN ACCESS Antibodies 2014, 3 206

Principles of antibodies with ultralong complementarity-determining regions and picobodies

“…The architecture of the ulCDR-H3s revealed that the knob is structurally isolated from the antibody via the stalk. This finding inspired protein engineering approaches to obtain antibody fusions by replacing the knob domain with proteins that have various biological activities 53 . For example, the knob of the bovine antibody BVL1H12 was replaced with bovine granulocyte-colony stimulating factor (bGCSF), resulting in a chimeric antibody bearing two bGCSF moieties (Fig.…”

Phage Display Technology, Phage Display System, Antibody Library, Prospects and Challenges

“…The source of the antibody library used for library preparation has a great influence on the type of antibody library generated. It may come from different hosts, not humans [11], and different immune responses in health and disease states will have a profound impact on the diversity of antibody lineages.…”

Broadly Neutralizing Bovine Antibodies: Highly Effective New Tools against Evasive Pathogens?

“…Therefore, these ultralong CDR H3 may be very amenable to engineering for therapeutic purposes. Previous efforts to engineer the cow ultralong CDR H3 have already shown that the knob structure can be replaced by bioactive peptides to target specific receptors, including CXCR4 [58] or replaced with cytokines to generate highly functional fusion proteins [59]. The bovine antibody scaffold is thus also a versatile platform that has the potential to generate novel therapeutics with enhanced kinetics, including longer plasma half-lives.…”