OGT’s protein biomarker platform, developed through its Sense Proteomic subsidiary, enables detection of circulating serum autoantibodies using a functional protein microarray technology. Binding of autoantibodies in patient serum to proteins on the arrays is used to identify a subset of protein antigens that provides a characteristic fingerprint for a given disease.
In our discovery studies, clinically relevant autoantibodies and their cognate antigens were identified and characterized to formulate a panel of antigens, which provided specific diagnostic information for the particular disease. This is then followed by validation of the panel using additional patient samples and development of a diagnostic test with clinical utility.
Sense Proteomic has developed an array with ~1,300, folded, functional human proteins. The proteins were selected on the basis of important cellular processes or disease association and have clinical relevance to cancer and autoimmune disease. The proteins are individually expressed as recombinant fusion proteins with a biotin-carboxyl carrier protein (BCCP) tag that is biotinylated in the host cell only when the target protein and tag are correctly folded (Figure 1). This enables specific, on-array affinity purification of folded proteins using streptavidin-coated slide chemistry.
Many autoantibody reactive epitopes are conformation-dependent structures (i.e., discontinuous epitopes) that may not be detectable using peptides or proteins that are not in the correct conformation. Sense’s technology ensures that only fully folded proteins with native epitopes presented are immobilized on the array surface, thereby offering maximum likelihood of discovering multiple clinically relevant autoantibodies in a single assay (Figure 2).