Scientists at the U.S. Food and Drug Administration (FDA) have developed a method in their laboratory for quickly measuring the amount of hemagglutinin (HA) antigen in standards used for potency testing of seasonal and pandemic influenza vaccines.
Seasonal and pandemic influenza is a significant public health threat and vaccination is the cornerstone for the prevention of influenza and its related complications, which can be severe. A fast and more accurate alternative method to measure influenza vaccine antigen content would facilitate more rapid preparation of reference standards and support production and availability of seasonal as well as pandemic influenza vaccines.
Vaccines that prevent influenza trigger production of antibodies against a protein called hemagglutinin (HA). These antibodies inhibit virus infection by blocking HA from binding to cells in the body. HA is therefore the key component of most influenza vaccines. Influenza vaccine potency is measured by determining the amount of HA that has the correct antigenic form. This method uses standards containing known amounts of HA.
The current method to measure the amount of HA in the standards takes a long time and is complicated by mixtures of proteins that have approximately the same size. The method developed by the FDA scientists is much faster and easily distinguishes between proteins that are similar in size. It measures the amount of HA using a combination of two modern technologies, liquid chromatography and mass spectrometry. This rapid alternative method could make standards for seasonal as well as pandemic vaccine potency testing available more quickly.
This new mass spectrometry-based method is based on an observation that allows “label-free” measurement of protein concentration. The advantage of the method developed by FDA is that it allows simultaneous measurement of the concentrations of other proteins in the mixture and does not require the use of reagents that are specific to a particular influenza virus. As a result, the method can easily be used to measure HA from any influenza virus. It can also be applied to measure the concentration of other viral proteins or impurities in a vaccine. This could help vaccine manufacturers determine the precise content of their products and provides a way to evaluate consistency of vaccine manufacture or improvements made to the manufacturing process.
Scientists in the Office of Cellular, Tissue, and Gene Therapies and the Office of Vaccines Research and Review conducted the study.
“Label-free mass spectrometry-based quantification of hemagglutinin and neuraminidase in influenza virus preparations and vaccines”
Influenza and Other Respiratory Viruses
3013 Jul;7(4) doi:10.1111/irv.12001 Epub 2012 Sep 3
Melkamu Getie-Kebtiea, Ishrat Sultanab, Maryna Eichelbergerb, Michail Altermana
aDivision of Cellular and Gene Therapies, OCTGT ⁄ CBER ⁄ FDA, Bethesda, MD, USA. bDivision of Viral Products, OVRR ⁄ CBER ⁄ FDA, Bethesda, MD, USA.