ORIGINAL RESEARCH article
Front. Immunol.
Sec. Vaccines and Molecular Therapeutics
Utilisation of monoclonal antibodies in the single radial immunodiffusion (SRID) assay to determine potency and stability for seasonal and pandemic influenza vaccines
Provisionally accepted
Jesse Bodle1,2*
David Burge1,2
Gopal Gounder1,2Kirsten Vandenberg1,2
Karen Laurie1,2Steven Rockman1,2,3*- 1CSL Innovation Pty Ltd, Melbourne, Australia
- 2Seqirus Australia Pty Ltd, Parkville, Australia
- 3The University of Melbourne, Melbourne, Australia
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Following manufacture, influenza vaccines must undergo potency testing as part of the process of release to market. The single radial immunodiffusion (SRID) assay is the current compendial assay for the measurement of antigen potency for protein-based influenza vaccines and stability of the vaccine over time. In this assay, polyclonal antibodies in animal serum bind to protein antigens in a gel, forming a visible precipitin ring. The size of this ring is compared to a calibrated standard to determine potency. The time to produce this polyclonal antiserum encumbers the release of both seasonal and pandemic vaccines for current licensed influenza vaccines. Monoclonal antibodies (mAbs) may be generated to influenza haemagglutinin (HA) proteins. Specific mAbs have been identified that provide reactivity to influenza virus strains over many years and influenza seasons, despite antigenic drift and vaccine update. mAbs may also be prepared prior to the dominance of a specific virus clade, providing opportunity for preparedness well in advance of the need for vaccine potency testing. We demonstrate that a combination or blend of two mAbs with alternate specificity for the globular head and stem of the HA protein enable the precipitation of antigen in a SRID assay format. This approach correlates with the compendial polyclonal animal sera based SRID assay for both potency and stability for seasonal and pandemic influenza viruses. A mAb-based SRID assay may significantly minimise the time to release of vaccine doses for current pandemic and seasonal influenza vaccines without the requirement of extensive clinical trials.
Keywords: Vaccine Potency, Potency test, Monoclonal antibody, mAb, Haemagglutinin, influenza vaccine, single radial immunodiffusion (SRID) assay, Antigen stability
Received: 31 Aug 2025; Accepted: 27 Oct 2025.
Copyright: © 2025 Bodle, Burge, Gounder, Vandenberg, Laurie and Rockman. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Jesse Bodle, jesse.bodle@seqirus.com
Steven Rockman, steve.rockman@seqirus.com
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.