Process steps:

1. Separate cDNA libraries containing diverse Ig heavy and light chain genes are constructed in a vaccinia virus-based vector.

2. These libaries are introduced, via infection, into human cells engineered to allow for high levels of expression of fully assembled antibodies on their cell surface.

3. A fluorescently tagged antigen binds to the minority of cells that express a specific antibody for this antigen.

4. These antigen-binding cells can be isolated in a high-throughput process using a combination of magnetic bead technology and high-speed cell sorting.

5. The recombinant viruses encoding the relevant heavy and light chains are extracted and characterized.

Process Benefits: An example of the power of the ACTIVMAb® technology is the ability to fully humanize an existing mouse or non-human antibody using V-gene replacement. In the membrane antibody selection process, the nonhuman VH gene is fixed and used to select human VL genes. Once these human VL genes are identified, they can be used to select human VH genes, thereby creating a fully human antibody specific to the same antigen and, in many cases, the same functional epitope as the original non-human antibody.