Immunity to Salmonella infection

Research output: ThesisDoctoral Thesis (compilation)

Abstract

The immune system has several strategies to combat infections. The present study investigates various aspects of the interaction between Gram negative bacteria, particularly Salmonella, and antigen presenting cells (APC). Salmonella is an intracellular bacterium infecting mice and man. Salmonella typhimurium infection in mice is a frequently used model for studying systemic Salmonella infection. One important type of APC is dendritic cells (DC), which initiate and direct immune responses. Bone marrow-derived DC were shown to mature after interacting with Salmonella in vitro. Maturation was detected by upregulation of costimulatory molecules and down modulation of phagocytic ability. Freshly isolated liver DC were shown to have the ability to phagocytose bacteria, present antigens on major histocompatibility complex class I (MHC-I) and MHC-II and produce cytokines upon Salmonella encounter in vitro. In a mouse model for chronic Salmonella infection we found that bacteria persisted for more than 6 months and that these mice had splenomegaly and high serum titers of Salmonella-reactive antibodies. In the spleen and liver of chronically infected mice, a dramatic infiltration of neutrophils was apparent. Moreover, redistribution of macrophages in the liver and DC in the spleen was shown. Bacterial virulence factors are important for Salmonella to infect and survive within host cells. Such a factor is AgfA fimbriae on Salmonella and the similar structure called curli expressed on Escherichia coli. Curli was shown to influence bacterial attachment to, but not internalization by, macrophages. These studies addressing the interaction between Salmonella and APC provide insight into important aspects of immune defense against Salmonella during acute infection, and further increase our understanding of immune parameters when infection is not successfully eradicated.

Details

Authors
  • Cecilia Johansson
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Immunology in the medical area

Keywords

  • Immunology, serology, transplantation, Immunologi, serologi, cytokines, antigen presentation, liver, dendritic cells, Salmonella, gram negative bacteria
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
  • [unknown], [unknown], Supervisor, External person
Award date2002 Jan 4
Print ISBNs91-628-5344-9
Publication statusPublished - 2002
Publication categoryResearch

Bibliographic note

Defence details Date: 2002-01-04 Time: 10:15 Place: Fernstršömsalen External reviewer(s) Name: Mowat, Allan Title: Prof Affiliation: [unknown] --- Article: I. Svensson, M., Johansson, C. and Wick, M.J., Salmonella enterica serovar Typhimurium-induced maturation of bone marrow-derived dendritic cells. Infect. Immun. (2000) 68:6311-6320. Article: II. Johansson, C. and Wick, M.J., Liver dendritic cells present bacterial antigens and produce cytokines upon Salmonella encounter. Manuscript. Article: III. Johansson, C., Börrzén, M. and Wick, M.J., Immune parameters of mice chronically infected with Salmonella. Manuscript. Article: IV Johansson, C., Nilsson, T., Olsén, A. and Wick, M.J., The influence of curli, a MHC-I-binding bacterial surface structure, on macrophage-T cell interactions. FEMS Immunol. Med. Microbiol. (2001) 30:21-29.