title: Slight Pro-Inflammatory Immunomodulation Properties of Dendritic Cells by Gardnerella vaginalis: The "Invisible Man" of Bacterial Vaginosis?
abstract: Bacterial vaginosis (BV), the most common genital infection in reproductive-aged women, is associated with increased risk of sexually transmitted infections. Its etiology remains unclear, especially the role of Gardnerella (G.) vaginalis, an anaerobic bacterium characteristic of the BV-alteration of the vaginal ecosystem. In the genital mucosa, dendritic cells (DCs) sense bacteria of the microenvironment via receptors and then orchestrate the immune response by induction of different T cell subtypes. We investigated the interactions between G. vaginalis and human monocyte-derived DCs using a wide range of bacterial concentrations (multiplicity of infection from 0.01 to 100), and the effects of this pathogen on PHA-induced lymphocyte proliferation. As observed by electron microscopy and cytometry, G. vaginalis reduced the internalization ability of DCs by forming extracellular clusters and induced neither DC maturation, nor DC secretion of cytokines, except at the highest dose with a very early DC maturation state. The same profile was observed on lymphocytes with significant increases of proliferation and cytokine secretion only at the highest bacterial concentration. Our findings indicate that G. vaginalis possesses slight immune-stimulating activities against DCs and T cells, reflecting thus a defective inflammatory response and giving rise to the atypical, non- or low-grade, inflammatory clinical disease profile.
authors.affiliation: UFR Médecine-Pharmacie, Clermont Université, Université d'Auvergne, UMR 1019 UNH, ECREIN, Laboratoire d'Immunologie, 63001 Clermont-Ferrand, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bertran
authors.affiliation: INRA de Theix, UMR 1019 UNH, ECREIN, 63122 Saint-Genès-Champanelle, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Brachet
authors.affiliation: UFR Médecine-Pharmacie, Clermont Université, Université d'Auvergne, UMR 1019 UNH, ECREIN, Laboratoire d'Immunologie, 63001 Clermont-Ferrand, France.
authors.forename: Marjolaine
authors.initials: M
authors.lastname: Vareille-Delarbre
authors.affiliation: UFR Médecine-Pharmacie, Clermont Université, Université d'Auvergne, UMR 1019 UNH, ECREIN, Laboratoire d'Immunologie, 63001 Clermont-Ferrand, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Falenta
authors.affiliation: Service d'Immunologie, CHU Clermont-Ferrand, 63001 Clermont-Ferrand, France.
authors.forename: Annie
authors.initials: A
authors.lastname: Dosgilbert
authors.affiliation: UFR Pharmacie, Clermont Université, Université d'Auvergne, UMR 1019 UNH, ECREIN, Laboratoire de Biochimie, 63001 Clermont-Ferrand, France.
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Vasson
authors.affiliation: UFR Pharmacie, Clermont Université, Université d'Auvergne, UMR CNRS 6023 LMGE, Laboratoire de Bactériologie, 63001 Clermont-Ferrand, France.
authors.forename: Christiane
authors.initials: C
authors.lastname: Forestier
authors.affiliation: UFR Médecine-Pharmacie, Clermont Université, Université d'Auvergne, UMR 1019 UNH, ECREIN, Laboratoire d'Immunologie, 63001 Clermont-Ferrand, France; Service d'Immunologie, CHU Clermont-Ferrand, 63001 Clermont-Ferrand, France.
authors.forename: Arlette
authors.initials: A
authors.lastname: Tridon
authors.affiliation: UFR Médecine-Pharmacie, Clermont Université, Université d'Auvergne, UMR 1019 UNH, ECREIN, Laboratoire d'Immunologie, 63001 Clermont-Ferrand, France; Service d'Immunologie, CHU Clermont-Ferrand, 63001 Clermont-Ferrand, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Evrard
mesh_terms: D058491:Bacterial Load; D049109:Cell Proliferation; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D005260:Female; D006194:Gardnerella vaginalis / Q000254:growth & development / Q000276:immunology*; D054884:Host-Pathogen Interactions; D006801:Humans; D056747:Immunomodulation; D008070:Lipopolysaccharides / Q000494:pharmacology; D009000:Monocytes / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D009092:Mucous Membrane / Q000276:immunology / Q000382:microbiology; D010835:Phytohemagglutinins / Q000494:pharmacology; D061251:Primary Cell Culture; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D014621:Vagina / Q000276:immunology / Q000382:microbiology; D016585:Vaginosis, Bacterial / Q000276:immunology / Q000382:microbiology / Q000473:pathology
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D010835:Phytohemagglutinins