Question

The purpose of using two different protein-specific monoclonal antibodies in ELISA is to Choose one: O A. provide multiple binding spots for the enzyme-linked signaling antibody O B. improve detection by having two different detection antibodies. O C. improve specificity by forming a "sandwich" with the antigen protein in the middle. OD. Improve detection by having two different immobilized capture antibodies

Answer 1

Ans: Improve specificity by forming a sandwich with the antigen protein in the middle.

Sandwich ELISA is a technique where the microtitre well is covered with a specific antibody. The sample containing the antigen protein is added and allowed to react with the antibodies coated on the surface of well to form antigen-antibody complex. After properly washing with buffers, a second enzyme linked antibody is added which is specific for the other epitopes of the antigen which ultimately reacts and binds with the antigen. The enzyme form colored products when substrate is added which confirms the presence of antigen and the rate at which color is formed is directly proportional to the amount of antigens.