Aging and eliciting agents: effect on murine peritoneal macrophage monokine bioactivity

Decreased responsiveness of the aged to infection may be associated with a decline in monokine production. Prior studies in macrophages have used different eliciting agents, and results have varied. We assessed the effect of age on interleukin-1 (IL-1), tumor necrosis factor (TNF), and interleukin-6 (IL-6) in unelicited, thioglycollate (TG)-elicited, and complete Freund's adjuvant (CFA)-elicited peritoneal macrophages. Resident macrophages or CFA-elicited macrophages from middle aged or aged mice produced significantly less monokine bioactivity than resident or CFA-elicited macrophages from young mice. Monokine bioactivity from TG-elicited macrophages from aged and middle aged mice was significantly increased when compared with macrophages of young mice. Eliciting agents may alter macrophage populations and interactions with other cells leading to changes in monokine bioactivity with aging.