Publications by authors named "Wiltrud M Kalka-Moll"

We determined the prevalence and spread of antibiotic resistance and the characteristics of ESBL producing and/or multi drug resistant (MDR) Escherichia coli isolates collected from urine samples from urology services in the Euregio Meuse-Rhine, the border region of the Netherlands (n=176), Belgium (n=126) and Germany (n=119). Significant differences in resistance between the three regions were observed. Amoxicillin-clavulanic acid resistance ranged from 24% in the Netherlands to 39% in Belgium (p=0.

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Article Synopsis
  • The adaptive immune system responds to foreign molecules by activating T and B lymphocytes to defend against pathogens.
  • Recent research highlights the importance of polysaccharides, previously thought to be ineffective T cell activators, showing that zwitterionic polysaccharides (ZPSs) can indeed stimulate immune responses.
  • This review explores how ZPSs modulate immune functions and their potential applications in developing vaccines for various health issues, including chronic inflammation and allergies.
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Abscess formation associated with secondary peritonitis causes severe morbidity and can be fatal. Formation of abscesses requires the presence of CD4+ T-cells. Zwitterionic polysaccharides (ZPSs) represent a novel class of immunomodulatory bacterial antigens that stimulate CD4+ T-cells in a major histocompatibility complex (MHC) class II-dependent manner.

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Zwitterionic capsular polysaccharides (ZPS) of commensal bacteria are characterized by having both positive and negative charged substituents on each repeating unit of a highly repetitive structure that has an alpha-helix configuration. In this paper we look at the immune response of CD8(+) T cells to ZPSs. Intraperitoneal application of the ZPS Sp1 from Streptococcus pneumoniae serotype 1 induces CD8(+)CD28(-) T cells in the spleen and peritoneal cavity of WT mice.

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We describe the recovery and identification of a bacterium that represents a new species of the genus Cupriavidus from cultures of respiratory tract specimens from two patients with cystic fibrosis (CF). The elucidation of the role of this species in CF lung disease will require an evaluation of a greater number of cases.

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Zwitterionic polysaccharides of the normal flora bacteria represent a novel class of antigens in that they correct systemic CD4(+) T-cell deficiencies and direct lymphoid organogenesis during colonization of the host. Presentation of these polysaccharides to CD4(+) T cells depends on major histocompatibility complex class II- and DM-dependent retrograde transport from lysosomes to the cell surface. Yet the phenotype and clonality of the immune response to the polysaccharide in the mature host immune system have not been studied.

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Bacterial capsular polysaccharides are virulence factors and are considered T cell-independent antigens. However, the capsular polysaccharide Sp1 from Streptococcus pneumoniae serotype 1 has been shown to activate CD4(+) T cells in a major histocompatibility complex (MHC) class II-dependent manner. The mechanism of carbohydrate presentation to CD4(+) T cells is unknown.

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Bacterial carbohydrates have long been considered T cell-independent antigens that primarily induce humoral immune responses. Recently, it has been demonstrated that bacterial capsules that possess a zwitterionic charge motif can activate CD4(+) T cells after processing and presentation by antigen-presenting cells. Here we show that these zwitterionic polysaccharides can prevent T helper 1-mediated fibrosis by signaling for the release of IL-10 from CD4(+) T cells in vivo.

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Article Synopsis
  • Carbohydrates, particularly zwitterionic polysaccharides (ZPSs) from bacterial capsules, can trigger strong CD4+ T-cell responses, challenging previous beliefs about carbohydrates not involving T cells.
  • Research shows that HLA-DR on antigen-presenting cells (APCs) is crucial for T-cell proliferation induced by ZPS, and this process involves nitric oxide-mediated conversion of ZPS in the endosomes.
  • ZPS treatment of APCs enhances surface expression of HLA-DR and costimulatory molecules, with the cellular immune response relying on the coordinated action of these molecules to activate ZPS-specific T cells effectively.
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Polysaccharides of pathogenic extracellular bacteria commonly have negatively charged groups or no charged groups at all. These molecules have been considered classic T cell-independent Ags that do not elicit cell-mediated immune responses in mice. However, bacterial polysaccharides with a zwitterionic charge motif (ZPSs), such as the capsular polysaccharides of many strains of Bacteroides fragilis, Staphylococcus aureus, and Streptococcus pneumoniae type 1 elicit potent CD4(+) T cell responses in vivo and in vitro.

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