Macrophage phagocytosis and membrane fluidity in mice: the effect of age and dietary protein.
Male C57BL/6NNia mice were used to investigate the effects of age and dietary protein intake on Fc and C3b receptor-mediated phagocytosis and on membrane fluidity. Six-month-old (adult) and 24-month-old (aged) mice were fed a 6% or 25% protein diet for 3, 5, or 6 weeks at which time thioglycollate elicited peritoneal macrophages were isolated. Both binding of IgG-coated sheep red blood cells to the macrophages and ingestion via the Fc-receptor were identical in all 4 groups after 3 and 6 weeks of feeding but were decreased at 5 weeks in the aged animals fed 6% protein. Phagocytosis via the C3b receptor was not depressed in either age group fed the low protein diet; it was, however, augmented significantly in the aged animals fed the 25% protein diet for 5 and 6 weeks. Membrane fluidity of the plasma membrane outer hemileaflet was monitored with an impermeant fluorescent probe. No changes were observed between adult and aged mice maintained up to 6 weeks on the diets.
D000375:Aging; D000818:Animals; D004044:Dietary Proteins / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D016177:Macrophage-1 Antigen; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D010587:Phagocytosis / Q000187:drug effects; D011951:Receptors, Complement / Q000502:physiology; D011961:Receptors, Fc / Q000502:physiology
D004044:Dietary Proteins; D016177:Macrophage-1 Antigen; D011951:Receptors, Complement; D011961:Receptors, Fc