Llama DNA Immunization and Isolation of Functional Single-Domain Antibody Binders

Area of Science:

• Immunology
• Biotechnology
• Molecular Biology

Background:

• Genetic immunization is a powerful tool for antibody generation, particularly for challenging targets like ion channels and receptors.
• While effective in small animals, DNA/RNA immunization faces challenges with immunogenicity in large mammals.
• Developing robust genetic immunization methods for large mammals is crucial for therapeutic antibody development.

Purpose of the Study:

• To establish and validate a method for genetic immunization in llamas.
• To generate heavy-chain IgG responses against epidermal growth factor receptor (EGFR).
• To produce single-domain antibodies (VHHs) with high affinity to EGFR.

Main Methods:

• Utilized a combination of biolistic transfection (gene gun) and intradermal injection (DERMOJET® device) for llama immunization.
• Developed protocols for gene gun bullet preparation and llama immunization procedures.
• Employed serology, phage-display library construction, panning, and VHH characterization for antibody assessment.

Main Results:

• Successfully elicited heavy-chain IgG responses in llamas against EGFR.
• Generated single-domain antibodies (VHHs) exhibiting nanomolar affinities for EGFR.
• Demonstrated the feasibility of the combined gene gun and intradermal injection technique for llama immunization.

Conclusions:

• The described genetic immunization method is effective in llamas for generating specific antibody responses.
• This approach enables the production of high-affinity VHHs against challenging targets like EGFR.
• The methodology provides a valuable tool for antibody discovery and development in large animal models.