Mechanism of a Decrease in Potency for the Recombinant Influenza A Virus Hemagglutinin H3 Antigen During Storage. Issue 3 (14th January 2014)

• Record Type: Journal Article
• Authors: Hickey, John M.; Holtz, Kathleen M.; Manikwar, Prakash; Joshi, Sangeeta B.; Mcpherson, Clifton E.; Buckland, Barry; Srivastava, Indresh K.; Middaugh, C. Russell; Volkin, David B.
• Is Part Of: Journal of pharmaceutical sciences. Volume 103:Issue 3(2014:Mar.)
• Page Start: 821
• Page End: 827
• Publication Date: 2014-01-14
• Subjects: Pharmacy -- Periodicals; 615.1
• DOI: 10.1002/jps.23848
• Languages: English
• ISSNs: 0022-3549

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The recombinant hemagglutinin (rHA)‐based influenza vaccine Flublok® has recently been approved in the United States as an alternative to the traditional egg‐derived flu vaccines. Flublok is a purified vaccine with a hemagglutinin content that is threefold higher than standard inactivated influenza vaccines. When rHA derived from an H3N2 influenza virus was expressed, purified, and stored for 1 month, a rapid loss of <italic>in vitro</italic> potency (∼50%) was observed as measured by the single radial immunodiffusion (SRID) assay. A comprehensive characterization of the rHA protein antigen was pursued to identify the potential causes and mechanisms of this potency loss. In addition, the biophysical and chemical stability of the rHA in different formulations and storage conditions was evaluated over time. Results demonstrate that the potency loss over time did not correlate with trends in changes to the higher order structure or hydrodynamic size of the rHA. The most likely mechanism for the early loss of potency was disulfide‐mediated cross‐linking of rHA, as the formation of non‐native disulfide‐linked multimers over time correlated well with the observed potency loss. Furthermore, a loss of free thiol content, particularly in specific cysteine residues in the antigen's C‐terminus, was correlated with potency loss measured by SRID. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:821–827, 2014</p> </abstract>