ID#: 22164
To inform selection of the vaccine viruses used in the seasonal influenza vaccine, Centers for Disease Control and Prevention (CDC) scientists use a test called the hemagglutinin inhibition (HI) assay to characterize influenza viruses according to the “antigens” on the virus’ surface. Antigens are molecular structures on the surface of viruses that are recognized by the immune system, and are capable of triggering an immune response, and antibody production. Antigens play a key role in the influenza virus’ ability to bind to, and enter cells in the nose, throat and lungs. The HI test measures how well antibodies made from an immune response against a specific influenza virus, bind to other influenza viruses, and thus inactivate them. Scientists also use the HI test to compare antigenic changes in currently circulating influenza viruses, to influenza viruses that have circulated in the past. Here, an HI machine is preparing to perform the HI test.
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Content Provider(s): CDC/ Emily Cramer
Creation Date: 2017
Photo Credit: Videographer: Todd Jordan
CDC Organization
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Copyright Restrictions: None - This image is in the public domain and thus free of any copyright restrictions.