Macrophage heterogeneity in prostaglandins and thromboxane synthesis: differential activation by Fc- and C3b-dependent bacterial phagocytosis.
Resident peritoneal macrophages, obtained from rats, were separated into subpopulations by centrifugation on a Percoll discontinuous density gradient. Nine fractions of pure macrophages were isolated. Each subpopulation was studied for Fc- and C3b-dependent bacterial phagocytosis and assayed for the related synthesis of PGE2, TxA2 and PGI2, measured by their stable metabolites TxB2 and 6-Keto-PGF1. The results show that with decreasing density, which corresponds to a greater maturity, the production of PGE2 increases and that of TxB2 and 6-Keto-PGF1 decreases. The cells of low density were mostly stimulated by IgG-opsonized bacteria, whereas those of high density responded preferentially to C3b- opsonized bacteria. This pattern is roughly similar to the one characterizing the phagocytosis via these two receptors although the correlation is not absolute. It can be concluded that enzymes involved in the metabolism of arachidonic acid, as well as receptors for C3b and IgG, are differentially expressed among resident macrophage subpopulations and thus during macrophage maturation.
Coquette
A
A
Laboratory of Immunology, Faculty of Medicine, Free University of Brussels, Belgium.
Boeynaems
J M
JM
Saint-Guillain
M
M
Vray
B
B
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D003179:Complement C3b / Q000502:physiology*; D011464:Epoprostenol / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000502:physiology*; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D010587:Phagocytosis; D051381:Rats; D013928:Thromboxane A2 / Q000096:biosynthesis
D001095:Arachidonic Acids; D007074:Immunoglobulin G; D013928:Thromboxane A2; D003179:Complement C3b; D011464:Epoprostenol