But in the case of the person who contains HIV, because they do have those antibodies against the agent, they will bind onto the antigen shown in diagram B. So these blue antibodies present in the blood of that person that contains HIV will bind onto the red antigens. Now the next question is how do we actually visualize the presence of this antibody antigen Complex well, we have to use a special antibody that we produced in the laboratory setting. And this antibody is manufactured in a way to basically contain an enzyme. So we have an antibody shown in green, and that antibody is created so that it contains an enzyme attached to it. And we'll see why that's important in just a moment.