title: Differentiated U937 cells exhibit increased bactericidal activity upon LPS activation and discriminate between virulent and avirulent Listeria and Brucella species.
abstract: In the study of interactions between facultative intracellular pathogens and macrophages, monocytic cell lines have the advantages of showing defined states of activation and lacking genetic variation among donors, thus yielding reproducible results. Nonpathogenic Escherichia coli K12 were killed at similar rates in the U937 cell line differentiated into macrophage-like cells by phorbol myristate acetate (PMA) or by the combination of retinoic acid (RA) and vitamin D3 (VD). Complete elimination was reached only when cells were activated by lipopolysaccharide for 30 min prior to infection, and it was further enhanced when bacteria were opsonized by specific immunoglobulin G. Both types of differentiation led to intracellular multiplication of virulent Listeria monocytogenes and to elimination of the animal pathogen Listeria ivanovii. For both strains, conditions for intracellular survival were more favorable in PMA-differentiated U937. During infection, RA/VD-differentiated U937 could discriminate between the human pathogen Brucella suis S1, which strongly multiplied, and the animal pathogen Brucella canis, which survived without multiplication. U937 cells differentiated by RA and VD therefore represent a basic model in bacteria-human macrophage interactions.
authors.affiliation: INSERM U-65, Département Biologie-Santé, Université de Montpellier II, France.
authors.forename: E
authors.initials: E
authors.lastname: Caron
authors.forename: J P
authors.initials: JP
authors.lastname: Liautard
authors.forename: S
authors.initials: S
authors.lastname: Köhler
mesh_terms: D001770:Blood Bactericidal Activity / Q000187:drug effects* / Q000502:physiology*; D002002:Brucella / Q000187:drug effects* / Q000472:pathogenicity*; D002006:Brucellosis / Q000382:microbiology; D002454:Cell Differentiation / Q000187:drug effects; D002762:Cholecalciferol / Q000494:pharmacology; D004926:Escherichia coli; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008087:Listeria / Q000187:drug effects* / Q000472:pathogenicity*; D008089:Listeria monocytogenes; D008088:Listeriosis / Q000382:microbiology; D008262:Macrophage Activation / Q000187:drug effects* / Q000502:physiology*; D008264:Macrophages / Q000382:microbiology* / Q000502:physiology*; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000382:microbiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014774:Virulence
chemical_list: D008070:Lipopolysaccharides; D002762:Cholecalciferol; D014212:Tretinoin; D013755:Tetradecanoylphorbol Acetate