Antibody Engineering of scFv and VHHs
One of the clear advantages of having a single domain (VHH) or single chain (scFv) antibody is the ability to engineer this into formats for its desired end use. As mentioned under Small Scale Antibody Production, it is quite straightforward to fuse the antibody to a Fc which can then allow traditional detection (mouse or rabbit Fc for diagnostics), a human Fc for potential therapeutic use, bispecific or trispecifics for multiple target use or increased half-life stability in vivo. The VHH antibodies are particularly amenable to manipulation and can be humanized, multimerized, engineered for intracellular penetration, increased stability, protease resistance, etc. It is also possible to do CDR grafting or domain swapping to engineer an existing antibody into a single domain VHH antibody.