Antigen is a given substance that stimulates a specific immune system.
Explanation:
Antigen is a substance that can stimulate an immune response by activating lymphocytes (white blood cells) which acts as body defence against infections. Antigen is divided into two which are,
1. Foreign antigen or heteroantigen which is a foreign substance that stimulates immune response.
2. Autoantigen self antigen is a substance in the body that stimulates immune response.
Because by damaging capsids, there is no place for the bad DNA to be stored. So the drug destroys the DNA so no more of the virus can be stored in the body.