Question

An enzyme-linked immunosorbent assay (ELISA, sandwich method) for a molecule, X, uses two antibodies, A1 and A2, both of which are able to specifically bind to X. In addition, A2 is attached to an enzyme, E, which catalyzes the oxidation of a colorless molecule, P, to a molecule with red color, P*. What is the correct sequence for binding of the various components in this assay?

a. Surface-E-A2-X-A1

b. Surface-A2-E-A1-X

c. Surface-A1-A2-E-X

d. Surface-A1-X-A2-E

e. Surface-A1-X-E-A2

Answer 1

Answer- Surface- A1- X-A2 -E

In sandwich ELISA technique, the capture antibody A1 is coated on the well (surface)for the blocking the non-specific binding sites,then antigen X was added. Following to that, detection antibody A2 is added for the binding with the antigen and forms the antigen-antibody complex.Then, E enzyme conjugated detection reagent is added, further substrate is added which gets converted into the colored product (detectable form).

For your better understanding, please go through this attachment-

A2 deletion antibod captons, Ab added. &. Antigent added AI Surface coloned produs. Enzymex substrate added. added. Sandwich ELISA).