Begin with a multi-well plate coated with a test vaccine and block non-specific interaction sites.
Acquire a serum sample from a mouse injected with the test vaccine.
This serum contains immunoglobulin G, or IgG, antibodies that recognize the test vaccine.
To the vaccine-coated wells, add serially diluted serum samples.
The IgGs bind to the vaccine. Wash to remove unbound antibodies.
Add peroxidase-conjugated secondary antibodies that bind to IgGs. Remove unbound secondary antibodies.
Add a chromogenic substrate. The peroxidase interacts with the substrate, generating a blue-colored product.
Introduce an acid to stop the reaction. The change in the pH turns the solution yellow.
Using a spectrophotometer, measure the color intensity of each well to determine the concentration of IgG in the serum sample.