Question

In an antibody detection ELISA, lab-purified antigen (coronavirus S protein, for example) is added to the wells first. Model this step using the solid black circles to represent the coronavirus S protein antigens. How is this step different than the first step in an antigen detection ELISA?

Answer 1

In an antibody detection ELISA, lab-purified antigen is added directly to the wells, while in an antigen detection ELISA, the wells are coated with antibodies specific to the antigen.

Step-by-step explanation:

The first step in an antibody detection ELISA is to add lab-purified antigen to the wells of a microtiter plate. The antigen, such as the coronavirus S protein, is represented by solid black circles in the model. This step is different from the first step in an antigen detection ELISA, where the antigen is not added directly to the wells.

Instead, in an antigen detection ELISA, the wells are coated with antibodies specific to the antigen, and the antigen present in the sample binds to these antibodies.