Question: How the bacteria and cells in our immune system keep us healthy?

Stephanie Dyson answered on 9 Mar 2015:

The cells in our immune system keep us healthy by identifying pathogens (things that cause us harm) and destroying them before they can get too comfortable and start multiplying at a rate that we cannot contain. The bacteria we have helps by training the immune system to respond in a certain way to certain things at a low level so that when we get a big infection the cells know how to behave