Stop sucking money away from the working/middle class in all countries and giving it to the rich.....there is a reason why the US is the richest country in the world and its because FDR knew a strong middle class would make everyone richer........they are going in the opposite direction now and it's not going to end well.

"Drugs " and "Immune response " are a little too vague to give a comprehensive response. The immune system is passive and active .....so do you mean a change in the status quo homeostasis?

Any molecule could be described as a drug if it changes the function of cells, organs...,etc

Allergies are a immune response but some might say our resident bacteria throughout our bodies is a continuous response against hostile organisms.

Antivenom created to protect us from venom is sometimes toxic if it has no venom to counteract.