Biochemical and Functional Characterization of Plasma Derived Human Celestrase 1

Abstract

Background C1-esterase inhibitor (C1-INH) is a protein derived from fresh frozen human plasma and is widely used in the treatment of Hereditary Angioedema. C1-INH product must have high purity with preserved functionality. Objective The aim of the study was to perform extensive characterization of human C1-esterase inhibitor (Celestrase 1) with special emphasis on functionality of the protein by different mechanisms along with its purity and structural elucidation. Design Comparative study. Methods This study describes the purification and characterization of an economically viable, highly pure and efficient human plasma-derived C1-INH prepared from cryopoor plasma by combination of chromatography steps, capable of removing protein contaminants. The purification process includes two orthogonal virus clearance steps -solvent detergent and virus retentive filtration and further, characterized by various biochemical and functional assays along with other commercially available entities. Results The developed process yields 0.75  ±  0.1 vials of C1-INH /L of cryopoor plasma with 44.4  ±  3.6% overall process recovery. Celestrase 1 shows comparability with an existing market comparator, with respect to its purity by different methods. Celestrase 1 proved its functionality in binding irreversibly to the complement protein by classical pathway of the complement system and in the Kallikrein system. Additionally, the antigen-to-biologic activity ratio an indicative of the functionality for Celestrase 1 (0.94) was found comparable to market comparator (0.79). Identity of the product was confirmed by Western blot analysis. The structural analysis of Celestrase 1 was found to be similar to market comparator and exists predominantly in α-helix secondary structure by Far UV Circular Dichroism (CD). Conclusion For the treatment of Hereditary Angioedema (HAE), the current study presents a pure, safe, and functionally efficient product that can meet the therapeutic needs of patients deficient in C1-INH.