The Retrocyte Display^® advantages

4-Antibody believes its Retrocyte Display^® technology is superior to existing antibody discovery methods for several reasons:

Freedom to operate for any target.

Retrocyte Display is free from patent or licensing constraints and can be used to create fully human antibodies against any target. In contrast, remaining licensing requirements and associated royalty stacking with many other antibody discovery technologies can limit the appeal of these methods for the discovery of fully human antibodies.

‘Better behaved’ antibodies.

All antibodies generated by Retrocyte Display are, from the first stages of the discovery process, expressed in B-lineage cells - the cells naturally producing antibodies in the immune system. Therefore, all necessary co-factors (chaperones, glycosylation enzymes, etc.) that ensure proper processing and expression of antibodies are present throughout discovery. In vitro B-lineage expression selects for antibodies that exhibit natural structural and functional properties, e.g. proper protein folding, antibody heavy-light chain assembly, glycosylation and disulphide bridge formation, which are frequently absent in non-lymphocyte, lower eukaryotic or prokaryotic expression systems. There is scientific evidence that therapeutic antibodies that are fully human and produced by lymphocytes are more likely to display desirable ‘drug-like’ behavior when administered to patients than antibodies produced by bacterial expression techniques or phage expression combined with genetic engineering. We expect antibodies derived from Retrocyte Display to be stable and compatible with further downstream clinical development and manufacturing processes.

Maximized efficiency and flexibility.

The Retrocyte Display platform utilizes full-length immunoglobulin constructs at all stages of our process to minimize the need for re-engineering and can be combined with any antibody library source: libraries from patients, libraries from any B cell source, semi-synthetic libraries, mutagenized antibody libraries, or focused series of initial antibody ‘hits’ resulting from screens using other technology platforms such as phage display or other display technologies. This offers unparalleled flexibility in tailoring or customizing the antibody discovery process depending on the requirements of the project or the needs of a customer.

Rapid generation of fully human analogs of non-human antibodies.

Retrocyte Display can be used in a two-step heavy and light chain shuffling process to convert a non-human antibody with desired properties into a fully human antibody with near-identical characteristics. Screening of a monoclonal antibody for conversion is performed against complex heavy chain libraries in the presence of antigen followed by light chain libraries iteratively enriching cells for antigen reactivity.

Creation of unique antibodies.

The in vitro library screening approach of Retrocyte Display enables the development of natural antibodies that would not be possible using either phage display or transgenic animal production alone. Retrocyte Display further allows highly efficient independent antibody heavy and light chain shuffling, thereby offering the possibility of creating unusual antibody specificities that cannot be found in natural immune repertoires.