gerKerth, Janna-LinaOrlikowsky, ThorstenStickeler, ElmarPeriphagozytäre Reaktionen bei neonatalen und adulten Monozyten nach Doppelinfektion mit E. coliinfo:eu-repo/classification/ddc/610Neonatal sepsis is the most important cause for neonatal deaths; E. coli is the second most common pathogen. In the neonatal, immature immune system, monocytes are, amongst others, responsible for early elimination of pathogens. This especially holds true for bacteremia and sepsis. After phagocytosis, monocytes secrete various pro- and anti-inflammatory cytokines and soluble factors which also induce the so called bystander kill. In an in vitro model, we simulated a two-time infection with E. coli. We postulated differences between neonatal and adult monocytes regarding phagocytic capacity, apoptosis rates and bystanderkill, the ability for double phagocytosis, cytokine secretion as well as killing of bacteria after phagocytosis. Monocytes were harvested from cord blood and peripheral blood of healthy adults and identified via FACS. Monocytes were infected with fluorescent E. coli on two subsequent days; afterwards, apoptosis rates were determined using Nicoletti or Annexin-V staining, respectively, and phagocytosis rates were determined using FACS. The effectiveness of killing was measured through killing assays, the secretion of IL-10 and TNF-alpha via ELISA. Both CBMO and PBMO are capable of double phagocytosis. The apoptosis rate of PBMO is higher than that of CBMO. CBMO have a significantly higher phagocytic capacity than PBMO. Apoptosis of CBMO was reduced after contact with the pathogen. Double infection led to a more efficient killing of bacteria in both groups. Measured by the IL-10-TNF-alpha-ratio, infection led to an increased secretion of TNF-alpha and a decreased production of IL-10 in CBMO. While our investigation is not without limitations, our results point to a possible contribution to sustained inflammation through an increased pro-inflammatory secretion of cytokines in a prolonged infection in the cord blood.Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen (2021). doi:10.18154/RWTH-2021-08976 = Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2021info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionRWTH Aachen University2021info:eu-repo/semantics/openAccessDEhttps://publications.rwth-aachen.de/record/828162https://publications.rwth-aachen.de/search?p=id:%22RWTH-2021-08976%22StudentsStudent Financial Aid ProvidersTeachersResearchersinfo:eu-repo/semantics/altIdentifier/doi/10.18154/RWTH-2021-08976