The scavenger cell pathway for lipoprotein degradation: specificity of the binding site that mediates the uptake of negatively-charged LDL by macrophages.

Macrophages isolated from a variety of organs in several animal species exhibit high affinity binding sites that recognize chemically modified proteins. One of these binding sites recognizes human plasma low density lipoprotein (LDL) in which the positive charges on the epsilon-amino groups of lysine have been removed or neutralized by chemical modification, thus giving the protein an enhanced negative charge. Effective treatments include reaction of LDL with organic acid anhydrides (acetylation or maleylation) and reaction with aldehydes, such as treatment with malondialdehyde.

[Whipple's disease].

Whipple's disease is characterized morphologically by macrophages in the small intestine which store PAS-postive material, as well as coarsening and atrophy of the intestinal villi, with pseudocystic cavitations. Without treatment it ends fatally due to irreversible diarrhoea and cachexia. Until 1963, only 90 cases had been diagnosed, most of them at autopsy.