Kinetics of interleukin-1 production by macrophages during infection with Listeria monocytogenes

Production of interleukin-1 (IL-1) by peritoneal macrophages from mice inoculated intravenously with Listeria monocytogenes was measured at increasing intervals of infection. IL-1 activity in the 24 h macrophage supernatants was determined by using the thymocyte PHA co-mitogenesis assay. IL-1 production increased as the infection progressed, reached a peak on the 9th or 10th day and then declined progressively to approach normal values by the 20th day. Our data on the kinetics of IL-1 levels during an acute infection with L.monocytogenes are discussed in relationship to the development of cell-mediated immunity and its regulation by macrophages.