Prostaglandin endoperoxide synthase (cyclooxygenase): ultrastructural localization to nonmembrane-bound cytoplasmic lipid bodies in human eosinophils and 3T3 fibroblasts.
Lipid bodies are nonmembrane-bound cytoplasmic inclusions which are prominent in cells engaged in inflammatory responses. Using postembedding immunogold localization with a primary anti-PGH (prostaglandin endoperoxide) synthase monoclonal antibody, PGH synthase was localized by electron microscopy to lipid bodies of two prostaglandin-forming cells: human eosinophils and murine 3T3 fibroblasts. Freshly isolated eosinophils from a hypereosinophilic syndrome donor and peripheral blood eosinophils maintained in coculture with 3T3 fibroblasts and granulocyte-macrophage colony-stimulating factor were studied. In both cell types, lipid bodies were the predominant structures labeled with anti-PGH synthase. Labeling was absent in controls. In both human eosinophils and murine fibroblasts, lipid bodies represent sites of localization of PGH synthase--the rate-limiting initial enzyme in the formation of prostaglandins--and may serve as specific sites of formation of cyclooxygenase-pathway-derived eicosanoids.
Dvoràk
A M
AM
Department of Pathology, Beth Israel Hospital, Boston, Mass 02215.
Morgan
E S
ES
Tzizik
D M
DM
Weller
P F
PF
D016475:3T3 Cells / Q000201:enzymology* / Q000648:ultrastructure; D000818:Animals; D004804:Eosinophils / Q000201:enzymology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D002479:Inclusion Bodies / Q000201:enzymology*; D051379:Mice; D016253:Microscopy, Immunoelectron; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis*
D011451:Prostaglandin-Endoperoxide Synthases