Bacterially induced activation of interleukin-18 in porcine intestinal mucosa

Vet Immunol Immunopathol. 2001 Feb 10;78(3-4):263-77. doi: 10.1016/s0165-2427(00)00266-x.

Abstract

Interleukin (IL)-18 is a cytokine with structural and functional properties similar to IL-1beta and IL-12, respectively. It is activated by caspase-1 cleavage, like IL-1beta, and induces interferon (IFN)-gamma, like IL-12. In order to study the role of IL-18 in the immune response to infectious diseases of mucosal surfaces we cloned and expressed porcine IL-18 and developed antibodies to the protein. Porcine IL-18 retains the caspase-1 cleavage site present in other mammalian IL-18 proteins, but has two potential N-linked glycosylation sites not found in those proteins. Porcine interleukin-18 mRNA and protein are expressed in immune tissues including lymph nodes and gut associated lymphoid tissues. Specific cell types containing IL-18 include lung and splenic macrophages, nonadherent spleen cells and intestinal epithelial cells. Although IL-18 transcription is moderately induced by lipopolysaccharide, the magnitude and total expression level are small compared to those of interleukin-1beta. In vivo and ex vivo infection of intestinal mucosa with Salmonella choleraesuis resulted in a decrease in size of IL-18, consistent with cleavage of the preprotein by caspase-1. Thus, IL-18 is present in mucosal tissues where it could play a role in the immune response to invading pathogens.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cells, Cultured
  • Cloning, Molecular
  • Interleukin-18 / biosynthesis*
  • Intestinal Mucosa / metabolism*
  • Macrophages, Alveolar / metabolism
  • Molecular Sequence Data
  • Molecular Weight
  • RNA, Messenger / metabolism
  • Swine / metabolism*

Substances

  • Interleukin-18
  • RNA, Messenger