Regensburg 2013 – scientific programme
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BP: Fachverband Biologische Physik
BP 28: Focus session: Intracellular Spectroscopy
BP 28.10: Talk
Thursday, March 14, 2013, 12:30–12:45, H44
CD-Spectroscopic Assessment of Potential Antigenicity of Negatively Charged Biopharmaceuticals — •Sven Brandt1, Krystin Krauel1, Kay Gottschalk2, Christiane Helm3, Andreas Greinacher4, and Stephan Block1 — 1ZIK HIKE - Humorale Immunreaktionen bei kardiovaskulären Erkrankungen, Fleischmannstr. 42-44, D-17475 Greifswald, Germany — 2Institut für Experimentelle Physik, Universität Ulm, D-89069 Ulm, Germany — 3Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Str. 6, D-17487 Greifswald, Germany — 4Institut für Immunologie und Transfusionsmedizin; D-17475 Greifswald, Germany
Platelet factor 4 (PF4), a protein with a high positive surface charge forms complexes with natural or artificial polyanions (PA). It is known that such complexes exhibit an antigen of the adverse drug reaction heparin induced thrombocytopenia (HIT) and that their antigenicity is three fold: (i) the molar ratio between PF4 and the PA, (ii) the charge density of the PA, and (iii) the chain length of the PA. To the best of our knowledge, we show for the first time by circular dichroism (CD) spectroscopy that the secondary structure of the protein is altered when complexes which are known to be antigenic are formed. Here we correlate the changes in the proteins secondary structure determined using CD spectroscopy with HIT antigenicity determined by ELISA. This allows us to assess potential antigenicity of negatively charged biopharmaceuticals without the necessity of in vivo studies or the use of antibodies isolated from immunized patients specific for the antigenic epitopes.