We have focused on the immune system<span> as a </span>system<span> that </span>helps maintain homeostasis<span> of the </span>body, and particularly on the intestine as the largest organ ofimmunity<span> in the </span>body<span>. The intestine is not a simple tube. ... The complex mechanism that maintains </span>homeostasis<span> is believed to depend on the </span>immune system<span> of the intestine.