Abcore’s antibody discovery platform ends with delivery of positive, unique VHH sequences. Often the next step in the process is to produce the single domain antibody for further testing. Depending on what further characterizations of the VHH protein will be done, we can produce the protein in a few different purities. Currently all our protein expression is done in E. coli.
The first step is to grow a culture in volumes varying between 5 ml up to multiple liters. Then the E. coli undergoes osmotic shock, where we can isolate the single domain antibodies from the periplasmic space. This “shockate” is about 80-90% pure and is pure enough for many further experiments. However, because it is a mixture, it is hard to quantify the amount of actual VHH present.
If the single domain antibody needs to be more pure or the concentrations need to be normalized for further experimentation, we can purify them further. In this case, Abcore purifies the VHH antibodies which have a His-tag via Ni-NTA (Nickel-NTA) chromatography. This results in a highly pure, known concentration of purified single domain antibody VHH protein.