Compared to IgG, human single domain VH antibodies have distinct pharmacological properties.
Key advantages of human VH include:
• Small size: With small size (12kDa) and functional without a light chain
• Ideal building block: VH antibodies are ideal building blocks for the generation of novel biological drugs with multiple advantages
• Tissue/Tumor penetration: They are small and can rapidly penetrate and accumulate in tissue/tumors while clearing quickly from circulation to minimize systemic toxicity.
• Low immunogenicity: They are fully human, no additional humanization is needed
• Customized half-life: Their modular configuration readily allows modifications and customization such as extending their half-life to match a relevant therapeutic treatment regime
Key advantages of our approach in developing human single domain VH antibodies are:
• Speed of development: Each discovery/optimization project finishes within weeks from target to final human VH antibodies
• Unlimited diversity and specificity: A highly diversified human VH library derived from more than 500 human donors in combination with on-demand diversification by inducible hypermutation
• Eukaryotic-based in vitro discovery system: Filters for well-expressing and manufacturable antibody candidates
• In vivo antigen-directed antibody maturation: Mimicking mammalian antibody diversification and affinity maturation processes
• FACS-based approach identifies relevant VH: Advanced process for identifying VHs with desired attributes
• Consistency across production batches: Recombinant monoclonal antibody with known amino acid sequences
• Difficult targets: Toxic, non-immunogenic, self-antigen, target with hidden epitopes or cell surface antigens
• Expressibility and manufacturability: Our expression/selection approach allows for selection of VH antibodies with intrinsic stability and expressibility.
A highly diversified naïve human yeast display VH antibody library derived from more than 500 donors is subjected to further diversification using Abzyme’s proprietary inducible hypermutation platform and selection steps. After three diversification/enrichment cycles, yeast cells displaying high affinity human VH to the target antigen are isolated by two consecutive FACS experiments. Additional enrichment and FACS sorting can be applied to increase antibody affinity or to select clones with improved activities. FACS-sorted single yeast display VHH clone candidates are further validated by cytoflow analysis using various antigen concentrations to rank order clones with affinity to antigens. Confirmed clones will be switched to a secretion mode for antibody production or transferred into a protein expression system of choice for production of final antibodies.