title: Antigen-specific B cells reactivate an effective cytotoxic T cell response against phagocytosed Salmonella through cross-presentation.
abstract: BACKGROUND
  The eradication of facultative intracellular bacterial pathogens, like Salmonella typhi, requires the concerted action of both the humoral immune response and the cytotoxic CD8(+) T cell response. Dendritic cells (DCs) are considered to orchestrate the cytotoxic CD8(+) T cell response via cross-presentation of bacterial antigens onto MHC class I molecules. Cross-presentation of Salmonella by DCs however, is accompanied by the induction of apoptosis in the DCs. Besides antibody production, B cells are required to clear Salmonella infection for other unknown reasons.
  
  
  RESULTS
  Here we show that Salmonella-specific B cells that phagocytose Salmonella upon BCR-ligation reactivate human memory CD8(+) T cells via cross-presentation yielding a Salmonella-specific cytotoxic T cell response. The reactivation of CD8(+) T cells is dependent on CD4(+) T cell help. Unlike the DCs, B cell-mediated cross-presentation of Salmonella does not coincide with apoptosis.
  
  
  CONCLUSIONS
  B cells form a new player in the activation of the cytotoxic effector arm of the immune response and the generation of effective adaptive immunity in Salmonella infection.
authors.affiliation: Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jelle
authors.initials: J
authors.lastname: de Wit
authors.forename: Yuri
authors.initials: Y
authors.lastname: Souwer
authors.forename: Tineke
authors.initials: T
authors.lastname: Jorritsma
authors.forename: Hanny
authors.initials: H
authors.lastname: Klaasse Bos
authors.forename: Anja
authors.initials: A
authors.lastname: ten Brinke
authors.forename: Jacques
authors.initials: J
authors.lastname: Neefjes
authors.forename: S Marieke
authors.initials: SM
authors.lastname: van Ham
mesh_terms: D017951:Antigen Presentation; D000942:Antigens, Bacterial / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000382:microbiology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D010587:Phagocytosis; D012480:Salmonella Infections / Q000276:immunology* / Q000382:microbiology; D012486:Salmonella typhimurium / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial