title: Dynamics of cytochemically distinct subpopulations of macrophages in elicited rat peritoneal exudates.
abstract: Qualitative and quantitative changes in rat peritoneal macrophage (M phi) subpopulations, differing in their ultrastructural peroxidatic staining characteristics were followed over the course of a thioglycollate (TG) broth-induced inflammatory response. In addition, selected functional features of the normal steady-state and 4-day TG-induced populations of M phi were compared. The steady-state population consisted primarily of M phi with peroxidatic staining limited to the nuclear envelope (NE) and rough endoplasmic reticulum (RER); such cells are called resident M phi. Within hours of TG injection, there was an influx of monocyte-derived exudate M phi, the number of which reached a maximum, by 24 hr. During the next 24 hr, the proportion of exudate M phi decreased with a concomitant increase in peroxidatic activity (PA)-negative M phi. These two cell types continued to predominate for the next 48 hr during which there was a gradual increase in resident M phi and so-called "exudate-resident" M phi, the latter of which exhibits both exudate and resident PA patterns. Thus, the 4-day TG-induced population consisted of four cytochemically distinct M phi subpopulations: approximately 50% PA-negative M phi, approximately 25% exudate M phi, approximately 15% resident M phi, and approximately 10% exudate-resident M phi. Differences in Fc receptors and complement receptors 1 and 3 were noted between the two populations in the presence of progenitors that give rise to colonies of M phi in liquid culture in response to murine-derived colony-stimulating factor 1. The implications of these results in regard to the origin(s) of M phi diversity are discussed.
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000276:immunology*; D002452:Cell Count; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D008262:Macrophage Activation; D008264:Macrophages / Q000145:classification* / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D051381:Rats; D011920:Rats, Inbred WF; D011951:Receptors, Complement / Q000032:analysis; D011961:Receptors, Fc / Q000032:analysis; D013864:Thioglycolates / Q000008:administration & dosage
chemical_list: D011951:Receptors, Complement; D011961:Receptors, Fc; D013864:Thioglycolates