The Vi Capsular Polysaccharide of Salmonella Typhi Promotes Macrophage Phagocytosis by Binding the Human C-Type Lectin DC-SIGN

• DOI: 10.1128/mbio.02733-22
• Publication Date: 2022-10-26T13:03:41Z
• Authors: Lillian F. Zhang; Bernd Lepenies; Sayuri Nakamae; Briana M. Young; Renato L. Santos; Manuela Raffatellu; Brian A. Cobb; Hirotaka Hiyoshi; Andreas J. Bäumler
• Keywords: DC-SIGN; C-type lectin

Capsular polysaccharides are common virulence factors of extracellular, but not intracellular bacterial pathogens, due to the antiphagocytic properties these surface structures. It is therefore paradoxical that Salmonella enterica subspecies serovar Typhi, an pathogen, synthesizes a virulence-associated (Vi) capsule, which exhibits properties. Here, we show Vi capsular polysaccharide has different functions when S. Typhi interacts with distinct subsets host phagocytes. The allowed selectively evade phagocytosis by human neutrophils while promoting macrophage phagocytosis. A screen C-type lectin receptors identified DC-SIGN as receptor involved in binding and capsulated Typhi. Consistent anti-inflammatory activity DC-SIGN, purified reduced inflammatory responses macrophages. These data suggest contributes pathogenesis typhoid fever. IMPORTANCE causative agent recent emergence strains resistant antibiotic therapy highlights importance vaccination managing effective vaccine against fever, role capsule plays during remains incompletely understood. identify for polysaccharide. Binding resulted pathogen macrophages induction cytokine response. Thus, interaction fever should be further investigated context development.