A balanced IL-1β activity is required for host response to Citrobacter rodentium infection

PLoS One. 2013 Dec 2;8(12):e80656. doi: 10.1371/journal.pone.0080656. eCollection 2013.


Microbial sensing plays essential roles in the innate immune response to pathogens. In particular, NLRP3 forms a multiprotein inflammasome complex responsible for the maturation of interleukin (IL)-1β. Our aim was to delineate the role of the NLRP3 inflammasome in macrophages, and the contribution of IL-1β to the host defense against Citrobacter rodentium acute infection in mice. Nlrp3(-/-) and background C57BL/6 (WT) mice were infected by orogastric gavage, received IL-1β (0.5 µg/mouse; ip) on 0, 2, and 4 days post-infection (DPI), and assessed on 6 and 10 DPI. Infected Nlrp3(-/-) mice developed severe colitis; IL-1β treatments reduced colonization, abrogated dissemination of bacteria to mesenteric lymph nodes, and protected epithelial integrity of infected Nlrp3(-/-) mice. In contrast, IL-1β treatments of WT mice had an opposite effect with increased penetration of bacteria and barrier disruption. Microscopy showed reduced damage in Nlrp3(-/-) mice, and increased severity of disease in WT mice with IL-1β treatments, in particular on 10 DPI. Secretion of some pro-inflammatory plasma cytokines was dissipated in Nlrp3(-/-) compared to WT mice. IL-1β treatments elevated macrophage infiltration into infected crypts in Nlrp3(-/-) mice, suggesting that IL-1β may improve macrophage function, as exogenous administration of IL-1β increased phagocytosis of C. rodentium by peritoneal Nlrp3(-/-) macrophages in vitro. As well, the exogenous administration of IL-1β to WT peritoneal macrophages damaged the epithelial barrier of C. rodentium-infected polarized CMT-93 cells. Treatment of Nlrp3(-/-) mice with IL-1β seems to confer protection against C. rodentium infection by reducing colonization, protecting epithelial integrity, and improving macrophage activity, while extraneous IL-1β appeared to be detrimental to WT mice. Together, these findings highlight the importance of balanced cytokine responses as IL-1β improved bacterial clearance in Nlrp3(-/-) mice but increased tissue damage when given to WT mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / immunology
  • Citrobacter rodentium / immunology*
  • Enterobacteriaceae Infections / genetics
  • Enterobacteriaceae Infections / immunology*
  • Enterobacteriaceae Infections / pathology
  • Female
  • Immunity, Innate*
  • Inflammasomes / genetics
  • Inflammasomes / immunology
  • Interleukin-1beta / genetics
  • Interleukin-1beta / immunology*
  • Macrophages / immunology*
  • Macrophages / pathology
  • Male
  • Mice
  • Mice, Knockout
  • NLR Family, Pyrin Domain-Containing 3 Protein


  • Carrier Proteins
  • Inflammasomes
  • Interleukin-1beta
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, mouse