Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: cheryl j on 21/12/2011 23:44:46

Title: How is immune response differentially controlled in different body compartments?
Post by: cheryl j on 21/12/2011 23:44:46

Foreign substances in the form of food and microorganisms  enter our mouths and digestive tracts, and other body cavities and seem to be tolerated by the white blood cells that roam about. But if a small particle of food is aspirated into the lungs, or the same organism or  foreign protein were injected directly into the blood stream, it would probably result in a violent reaction. Why do immune cells react in different ways in different parts of the body? How do they know where they are? Or am I way off track?

Title: Re: immunology question
Post by: CliffordK on 22/12/2011 05:57:41

I think that is an excellent question.

My guess is that white blood cells are more or less limited to the vascular and lymphatic systems.  Your epithelial layers and mucosa would present a barrier for them. 

Also, the macrophages and white blood cells can travel around cells, not through them, so they might have troubles penetrating  a continuous cellular barrier.

The GI system does, however, host a lot of white blood cells, with the appendix being full of them.

While the White Blood Cells, as well as the antibodies, appear to travel through the blood and lymph systems, the macrophages tend to be tissue specific.