The Retrogenix cell microarray technology is highly sensitive with a low rate of false positives. Typically, one or two hits will be identified and shown to be reproducible and specific to the test ligand – these will be confirmed as part of our standard screen. Where screening has been performed using a fluorescence read-out, Retrogenix scientists can now use an orthogonal approach to further validate these hits. This is achieved by performing flow cytometry analysis in order to confirm the specific interactions.

Our flow cytometry service routinely follows on from a full study. This allows clients to opt into the service dependent on results rather than commit upfront. We are frequently able to use materials that are already available to us at the end of the main screen, avoiding the need to produce and ship further samples to our UK labs.

Retrogenix’s flow cytometry screen takes around 2-3 weeks and provides key additional data to support interpretation of the results from a full receptor identification, target deconvolution or off-target screen.

Expression vectors encoding the hits identified by cell microarray screening, along with appropriate control vectors, are used to transfect HEK293 cells. Live transfectants are then incubated with the test ligand and controls (and with any fluorescent detection antibodies that are required). Each set of transfectants is then analysed by flow cytometry and the results interpreted by Retrogenix scientists.