Question

How are antigens detected?

Answer 1

Where there is smoke there is fire!

Explanation:

Antigen in the blood causes the immune system to produce antibodies (which you can say are like soldiers). So if we want to know if a particular antigen is present in blood, you can just look for the antibodies. It's kind of like, "where there's smoke there's fire."

To get a better picture of how it works :)

Source: https://www.pinterest.com/pin/133067363959444860/