Characterisation of the post-translational modifications of a novel, human cell line-derived recombinant human factor VIII

Introduction: Host cell lines used for recombinant protein expression differ in their ability to perform post-translational modifications (PTMs). The currently available recombinant human FVIII (rhFVIII) products are produced in mammalian, non-human cell lines. For rhFVIII, glycosylation and sulfation are vital for functionality and von Willebrand factor (VWF)-binding affinity. Here we present the characterisation of the PTMs of a novel, human cell line-derived recombinant human FVIII (human-cl rhFVIII). rhFVIII expression in a human cell line avoids expression of undesirable mammalian glycoforms like Gal alpha 1-3Gal beta 1-GlcNAc-R (alpha-Gal) and N-glycolylneuraminic acid (Neu5Gc), which constitute epitopes antigenic to humans. Materials and methods: We describe sulfation analysis, glycan profiling and characterisation using liquid chromatography-mass spectrometry and high performance anion exchange chromatography with pulsed amperometric detection. Results and conclusions: Human-cl rhFVIII is confirmed to be sulfated and glycosylated comparable to human plasma-derived FVIII. Most importantly, human-cl rhFVIII is devoid of the antigenic Neu5Gc or alpha-Gal epitopes observed in Chinese Hamster Ovary-and Baby Hamster Kidney-derived rFVIII products. Both the avoidance of non-human glycan structures and the achievement of complete sulfation are proposed to lower the intrinsic immunogenicity of human-cl rhFVIII compared with current rFVIII products. (C) 2012 Elsevier Ltd. All rights reserved.