Screening secreted proteins

A more comprehensive off-target screen

Human cell microarray technology has long been the leading tool for assessing potential off-target binding against human plasma membrane proteins. However, off-target binding to secreted proteins also has the potential to cause clinical toxicity or alter the pharmacokinetic profile of biotherapeutics in development. As such, Retrogenix has adapted its technology to accommodate secreted proteins, creating a more powerful screen whilst maintaining a robust, high quality platform with a low rate of false positive results.

Tethering secreted proteins

As secreted proteins are not naturally localised on the cell surface, novel cDNA constructs have been developed which result in expression of ‘secreted’ proteins fused to inert transmembrane and intracellular domains. As these proteins are tethered to the membrane, binding can be detected using the same workflow as the plasma membrane library. Extensive testing and validation work has confirmed that binding of known ligand:secreted protein pairs could be identified consistently.

Building a high quality ‘secreted’ library

Key to the reliability of the cell microarray screen has been the large, high quality library of plasma membrane proteins that are available for binding. Using a rigorous bioinformatics approach and collaborating with toxicology teams from four major pharmaceutical companies we have generated a ‘high confidence’ list of secreted proteins for priority inclusion in the library. Over these, >75% are now expressed in the Retrogenix collection, with more under development.

Retrogenix’s cell microarray libraries now have >5,500 proteins for screening which is the largest set of plasma membrane and secreted proteins expressed in human cells. As data from our specificity screens are used to support IND submissions it has been essential to ensure that the technology retains its high success rates throughout this expansion so that it now provides even greater confidence when assessing the specificity of a novel biotherapeutic or cell therapy.

Read our case study for more details of how the tethered secreted library has been developed and tested.

See case study

Download our poster: “Screening the secretome for off-target binding using  human cell microarray technology.”

Download poster

Pfizer
The University of Sheffield
Aveo Oncology - The Human Response
Theraclone Sciences
BioInvent
AstraZeneca
Bluebird Bio
glycotope_logo
The Center for Infectious Disease Research
Compugen Logo
The University of Copenhagen
Lund University
MedImmune
NIH - National Institutes of Health
The University of Pennsylvania
Scripps Florida - The Scripps Research Institute
Peptinnovate Ltd - Unlocking Nature's Potential
We are very happy with our collaboration with Retrogenix, and how their platform has delivered.
Dr. Björn Frendéus, Vice President of Pre-clinical Research at BioInvent International A/B