For some applications conventional antibodies might not be suitable due to their size or the size of the requested antigen. Therefore, we offer the generation of recombinant camelid heavy-chain only antibodies. Those antibodies - highly stable and small in size - reveal a complete new spectrum of antigen-binding in the field of biodiagnostics. The selection of appropriate binders is realized by phage display screening of our own naive camelid library. If desired, we draft the variable binding part to the constant part of the camelid immunoglobulin in order to produce recombinant camelid heavy-chain only full length antibody molecules or any chimeric option you need for your projects.
In order to make our contribution to fight against the actual pandemic we developed novel camelid binders specific for the S (spike) protein of SARS-CoV-2.
We screened our naive library against the recombinant Spike protein and identified a suitable phage pool with potential candidates.
During our phage panning rounds we could nicely see a specific increase of binding events to the recombinant S protein.
In the next step we picked the single clones, sequenced them and analysed their relationship. We found that seven potential candidates showed a unique VHH sequence with specific hallmarks. These candidates were chosen for a recombinant protein expression either as nanobody format or full length heavy chain antibody. In order to build up immunoassay systems based on camelid antibodies the full length heavy chain antibody formats were titrated for the best performance.
Also a HRP coupling procedure was established to provide secondary antibody reactions in the system. For recombinant S protein a sensitivity of less than 1 µg/mL could be achieved in the ELISA. Further characterizations showed a potent neutralising efficacy for four out of the seven identified candidates and a Kd value in the nanomolar range. With our workflow we can provide an allround solution for the generation of camelid binders and the set up of potential immunoassay detection systems.