Role of Macrophage Scavenger Receptors in Response to Listeria monocytogenes Infection in Mice

摘要: Type I and type II macrophage scavenger receptors (SR-A I/II) recognize a variety of polyanions including bacterial cell-wall products such as lipopolysaccharide, suggesting role for SR-A I/II in immunity against infection. I/II-deficient (MSR-A−/−) mice were more susceptible to infection with listeriolysin-O (LLO)-producing Listeria monocytogenes. After infection, Kupffer cells wild-type (MSR-A+/+) phagocytized larger numbers than those MSR-A−/− mice. The number the diameter hepatic granulomas MSR-A+/+ L. monocytogenes replicated at higher levels liver compared mice, macrophages from showed impaired ability kill vitro. However, similar listericidal activity isogenic mutant an inactivated LLO gene. listerial phagocytic activities treated anti-SR-A antibody (2F8) significantly untreated macrophages, indicating that function receptor Electron microscopy revealed most had been eliminated lysosomes vivo In contrast, rapidly lysed phagosomal membrane escaped cytosol 2F8 before phagosome-lysosome fusion. These findings imply plays crucial host defense not only by functioning but also mediating mechanisms through regulation LLO-dependent escape macrophages.