Rapid and Direct VHH and Target Identification by Staphylococcal Surface Display Libraries

Area of Science:

• Biotechnology
• Immunology
• Microbial Surface Display

Background:

• Identifying specific antibody-antigen interactions is challenging without prior knowledge of one partner.
• Immune responses to complex mixtures like whole organisms or tumor extracts generate diverse antibodies.
• Existing methods often require prior knowledge, limiting unbiased discovery.

Purpose of the Study:

• To develop a surface display system for simultaneous identification of camelid single-domain antibodies (VHH) and their target antigens.
• To enable rapid and unbiased discovery of antibody-target interactions from complex immune responses.

Main Methods:

• Camelid VHH libraries were displayed on the surface of *Staphylococcus aureus* using sortase enzyme-mediated covalent attachment to peptidoglycan.
• The sortase reaction allowed for reversible VHH display and recovery from the bacterial surface.
• Staphylococcal surface display libraries were screened using immunoprecipitation (IP) for VHH and target identification.

Main Results:

• A stable bacterial surface display platform was successfully established.
• The platform enabled rapid and simultaneous identification of VHH and their cognate antigens.
• Displayed VHH could be efficiently recovered for downstream applications.

Conclusions:

• The novel staphylococcal surface display platform provides a robust method for unbiased antibody-antigen discovery.
• This system accelerates the identification of VHH binders and their targets, even from complex immunizations.
• The technology is suitable for various downstream applications requiring recovered VHH fragments.