detection of Ab-Ag reactions in SERUM

ELISA:

• microplate coated with Ag is used
• we add serum and see if it has the antibodies (primary antibodies)
  • observed as color change
• excess Ab is washed
• we add conjugate Ab → binds to primary Ab
  • it is attached to an enzyme
• wash again
• add a substrate
  • reacts with enzyme to produce the color change
• wash again
• put the plate in a reader and get the results (numbers)

washing is done by a specific instrument

reading is done by a specific instrument

each plate has:

1. a specific washing solution
2. a specific choice of wavelength for the reader