John Richard Seavitt
jrseavit at artsci.wustl.edu
Wed Apr 8 23:42:24 EST 1998
On Wed, 8 Apr 1998, Season Wilcox wrote:
> I'm a college student trying to find out some information on respiratory
> bursts in macrophage. Mostly what I am looking for is the chemicals
> that are involved in activating this and how it all works.
This is something that is, admittedly, not so well covered in average
immunology texts. As I suspect you know, activation of macrophage or
other monocyte cell lines by interferon-gamma or IFNg/lipolysaccharide
leads to the production of reactive oxygen and nitrogen intermediates,
respectively. This is experimentally observable, in the case of ROI, by
the consumption of oxygen from whatever you've got the cells in, hence the
name, oxidative burst. The ROI/RNI have shown to be required for
clearance of various pathogens in animal models of disease.
"ROI" is a catchphrase for the reactants you can generate from reduced
oxygen with the right enzymes, which happen to be IFN-g inducible in
monocytes (Gee!). These reactants include, but are not limited to,
hydrogen peroxide and hypoclorous acid (that'd be bleach), which are of
obvious utility in killing phagocytosed pathogens.
Anyway, the enzymatic pathways that create ROIs are a bit boring, and can
be looked up without too much trouble. Check out our friends NADPH
oxidase, superoxide dismutase, and myeloperoxidase.
You'd probably find the generation of RNIs fairly interesting, since the
starting reactant is an amino acid, instead of unfixed oxygen.
"Seek Enlightenment: Thwack someone upside the head with a big stick."
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