Measuring Immunoglobulin G Levels Against a Test Vaccine in a Mouse Serum

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.