Enzo Life Sciences BioSims Conformational ELISA kits

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Enzo Life Sciences has introduced a novel line of conformational ELISA kits providing a sensitive, systematic and robust measurement of biosimilar conformation comparability at the molecular level.

The kit allows for 3D conformational comparison and higher-order structure (HOS) characterisation between biosimilars and marketed MAbs. The technology can be applied to many stages of biologics development. The assay uses more than 30 polyclonal antibodies to cover an entire Mab, thereby measuring its surface-epitope distribution systematically and sensitively.

The assay is in a sandwich ELISA format where the plate is coated with a panel of antibodies raised against peptides derived from the full length protein sequence of a biologic. Taken individually, each of these antibodies is strongly antigenic to the peptide sequence that was used in its production. However, when these peptides are incorporated into a full length correctly folded protein, the antigenicity of many of them is masked by the 3D structure of the protein and only a limited number of the antibodies respond. The result is a histogram which can be likened to a ‘fingerprint’ for a correctly folded biologic.

For a biosimilar, if the protein is correctly folded and glycosylated, the ‘fingerprint’ will match that of the biologic. If it is not correctly folded, previously masked peptide sequences will be exposed and will be recognised by the antibody made to that exposed sequence. In this way, changes in the ‘fingerprint’ generated by the ELISA will point out differences between the biosimilar and authentic biologic.

The product detects small amounts of conformational impurity (≥0.1%) and correlates well with bioassays and glycosylation analysis. Applications include monoclonal antibody development; antibody-drug conjugates; cell-line selection; process development; formulation development; comparability studies; and product characterisation.