Th17 cells are the dominant T cell subtype primed by Shigella flexneri mediating protective immunity

J Immunol. 2010 Feb 15;184(4):2076-85. doi: 10.4049/jimmunol.0900978. Epub 2010 Jan 20.

Abstract

The T cell response to Shigella, the causative agent of bacillary dysentery, remains poorly understood. Using a murine model of infection, we report that Shigella flexneri primes predominately IL-17A- and IL-22-producing Th17 cells. Shigella-specific Th1 cells are only significantly induced on secondary infection, whereas specific Th2 and CD8(+) T cells are undetectable. Apart from Th17 cells that are primed in a MHC class II- and IL-6-dependent, but IL12/23p40-independent manner, we identified gammadelta T cells as an additional but minor source of IL-17A. Priming of IL-17A(+) gammadelta T cells is dependent on IL12/23p40, but independent of MHC-class II and IL-6. Th17 cells have emerged as important players in inflammatory, autoimmune, and infectious diseases. Among the yet unresolved questions is their role in long-term immunity to pathogens. In this study, we show that the elicited S. flexneri-specific Th17 pool gives rise to an enhanced recall response up to 12 mo after priming, suggesting the presence of a long-term memory state. The clearance of primary infection is impaired in the absence of T cells, but independently of IL-17A. However, after reinfection, IL-17A produced by S. flexneri-specific Th17 cells becomes important to ultimately restrict bacterial growth. These findings bring new insights into the adaptive immune response to Shigella infection and highlight the importance of pathogen-specific Th17 cell immunity for secondary immune protection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Dysentery, Bacillary / immunology*
  • Dysentery, Bacillary / microbiology
  • Dysentery, Bacillary / prevention & control
  • Immunodominant Epitopes / immunology
  • Immunologic Memory
  • Interleukin-17 / biosynthesis*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Shigella flexneri / immunology*
  • T-Lymphocyte Subsets / immunology*
  • T-Lymphocyte Subsets / metabolism
  • T-Lymphocyte Subsets / microbiology*
  • T-Lymphocytes, Helper-Inducer / immunology*
  • T-Lymphocytes, Helper-Inducer / metabolism
  • T-Lymphocytes, Helper-Inducer / microbiology*
  • Th1 Cells / immunology
  • Th1 Cells / metabolism
  • Th1 Cells / microbiology
  • Th2 Cells / immunology
  • Th2 Cells / metabolism
  • Th2 Cells / microbiology

Substances

  • Immunodominant Epitopes
  • Interleukin-17