What is the term for the body's response caused by the immune system being activated by antigens?

I was working on a creative project a few years ago, and during two years of almost manic work, I ate almost nothing but chicken delivered from Papa John's. It was fast and good. After eating this way for over a year, I was hospitalized with severe gastric distress. It turned out that all the antibiotics in all that chicken had wiped out my gut bacteria, and I was a pretty sick puppy.

Sometimes your immune system is over reactive, like with psoriatic arthritis. Finding the right biologic and a good doctor was life saving for me. Couldn't live with that pain

I did study anatomy and physiology.