Multi-spanning membrane proteins, such as ion channels, GPCRs, ligand receptors, cell adhesion molecules, and etc, are important targets of ~50% of all small-molecule drugs but only 3 therapeutic monoclonal antibodies are available due to the challenges of targeting the extracellular loop (ECL) domains in membrane proteins. Traditional approaches of targeting the ECL domains in membrane proteins involve immunizing animals with full-length membrane proteins assembled into liposomes. Such approaches lack the site specificity in ECL domains so often require extensive epitope mapping in order to identify the right antibody.

BiCell Scientific Inc researchers have discovered that short-peptide antigens (13-19 amino acids) can be engineered into cyclic forms resembling their endogenous structures in the ECL domains of multi-spanning membrane proteins. BiCell Scientific’s approach allows developing site-specific recognition antibodies against any sequence in the extracellular loop (ECL) domains of membrane proteins. These ECL targeting antibodies can be used as blockers, neutralizing molecules, signaling molecules, CAR-T receptors and many more, for researches and therapeutics.