In addition to our antibody production services and phage display library screening services, Biomolecular Discovery Services offers
several other antibody production and development services. Contact us today to learn more and to request more information.
The advantages of selective antibodies and scaffold-based binders are many. The power of in vitro allows for choosing high-affinity binders, preferential on/off rate, specificity for one family member antigen from related molecules, antibodies targeted to a specific epitope, and other conditions that may be advantageous to the properties of the binder (stability, gentle elution, metal ion dependency, etc). Unlike traditional monoclonal antibodies, you choose from a very high diversity of molecules and will have a recombinant clone of the antibody which facilitates production, manufacturing and reproducibility as well as the ability to engineer the antibody into different formats and with different tags for detection and purification. BDS can create and screen custom phage libraries from various sources- human PBMCs, camelids, and immunized animals (camelids, mice, rabbits, sheep, rats).
This mode of expression for VHH and scFv antibodies is in E. coli and the antibodies will have both an N-terminal FLAG and a C-terminal HIS tag. Yield will average 100-200 ug for small-scale production (usually higher for VHH) which can be scaled up for increased yields. The antibodies are purified via the HIS tag by Ni-NTA chromatography and should be about 90% pure. Both scFv and VHH can be engineered into a traditional antibody format (see Antibody Engineering) by fusing onto a Fc backbone. These antibodies are then produced in the mammalian expression system with resulting yields of -ug and are purified via Protein A.
One of the clear advantages of having a single-chain antibody is the ability to engineer this into formats for its desired end use. As mentioned under 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.
One of the most common problems with an antibody that has the desired specificity is that the affinity is not sufficient. It is common for antibodies selected from Naïve libraries to require affinity maturation. However, existing antibodies can also have their affinity improved by this approach. A specific library is typically made of the antibody of interest with random mutations, some of which will improve affinity. The library is selected under appropriate conditions and the resulting molecules are further characterized for their resulting affinity compared to the parent molecule. Specific regions can also be targeted for mutagenesis as well.
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Learn more about our additional services at Biolmolecular Discovery Services. We'll be happy to answer any questions and to get started working with us.