E W Skjeflo1, D Christiansen2, A Landsem3, J Stenvik4, T M Woodruff5, T Espevik6, E W Nielsen7, T E Mollnes8. 1. Research Laboratory, Nordland Hospital, Bodø, Norway; Faculty of Health Sciences, K.G. Jebsen TREC, UiT - The Arctic University of Norway, Tromsø, Norway. Electronic address: espenwskjeflo@gmail.com. 2. Research Laboratory, Nordland Hospital, Bodø, Norway. 3. Research Laboratory, Nordland Hospital, Bodø, Norway; Faculty of Health Sciences, K.G. Jebsen TREC, UiT - The Arctic University of Norway, Tromsø, Norway. 4. Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Clinic of Medicine, St. Olavs Hospital HF, Trondheim University Hospital, Trondheim, Norway. 5. School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia. 6. Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway. 7. Research Laboratory, Nordland Hospital, Bodø, Norway; Department of Anesthesiology, Nordland Hospital, Bodø, Norway; Faculty of Professional Studies, University of Nordland, Bodø, Norway. 8. Research Laboratory, Nordland Hospital, Bodø, Norway; Faculty of Health Sciences, K.G. Jebsen TREC, UiT - The Arctic University of Norway, Tromsø, Norway; Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Immunology, Oslo University Hospital and K.G. Jebsen IRC, University of Oslo, Oslo, Norway.
Abstract
BACKGROUND: Sepsis is a dysregulated host response to infection. The aim of this study was to investigate the effects of complement- and CD14 inhibition on phagocytosis of live and dead Gram-negative and Gram-positive bacteria in human whole blood. METHODS: Lepirudin-anticoagulated blood was incubated with live or dead E. coli or S. aureus at 37 °C for 120 min with or without the C5aR1 antagonist PMX53 and/or anti-CD14. Granulocyte and monocyte phagocytosis were measured by flow cytometry, and five plasma cytokines by multiplex, yielding a total of 28 mediators of inflammation tested for. RESULTS: 16/28 conditions were reduced by PMX53, 7/28 by anti-CD14, and 24/28 by combined PMX53 and CD14 inhibition. The effect of complement inhibition was quantitatively more pronounced, in particular for the responses to S. aureus. The effect of anti-CD14 was modest, except for a marked reduction in INF-β. The responses to live and dead S. aureus were equally inhibited, whereas the responses to live E. coli were inhibited less than those to dead E. coli. CONCLUSION: C5aR1 inhibited phagocytosis-induced inflammation by live and dead E. coli and S. aureus. CD14 blockade potentiated the effect of C5aR1 blockade, thus attenuating inflammation.
BACKGROUND:Sepsis is a dysregulated host response to infection. The aim of this study was to investigate the effects of complement- and CD14 inhibition on phagocytosis of live and dead Gram-negative and Gram-positive bacteria in human whole blood. METHODS: Lepirudin-anticoagulated blood was incubated with live or dead E. coli or S. aureus at 37 °C for 120 min with or without the C5aR1 antagonist PMX53 and/or anti-CD14. Granulocyte and monocyte phagocytosis were measured by flow cytometry, and five plasma cytokines by multiplex, yielding a total of 28 mediators of inflammation tested for. RESULTS: 16/28 conditions were reduced by PMX53, 7/28 by anti-CD14, and 24/28 by combined PMX53 and CD14 inhibition. The effect of complement inhibition was quantitatively more pronounced, in particular for the responses to S. aureus. The effect of anti-CD14 was modest, except for a marked reduction in INF-β. The responses to live and dead S. aureus were equally inhibited, whereas the responses to live E. coli were inhibited less than those to dead E. coli. CONCLUSION:C5aR1 inhibited phagocytosis-induced inflammation by live and dead E. coli and S. aureus. CD14 blockade potentiated the effect of C5aR1 blockade, thus attenuating inflammation.
Authors: Ranjit K Sahu; Sandhya Xavier; Daniel Chauss; Luopin Wang; Claude Chew; Ronald Taylor; William B Stallcup; Jennie Z Ma; Majid Kazemian; Behdad Afzali; Jörg Köhl; Didier Portilla Journal: Am J Physiol Renal Physiol Date: 2022-04-04