So let's begin by examining indirect Eliza. So the entire point of indirect Eliza is to basically test for the presence of some specific type of antibody. So let's discuss the HIV agent. So let's suppose we have an individual who contracts HIV, and what that means is in their blood sample, in their blood, they're going to contain the antibodies against the antigen found in the HIV agent. So we can use indirect Eliza, for example, to test for the presence of the antibodies against that HIV agent. And that's exactly what we're going to use to demonstrate how this process actually works.