Mouse beta-defensin 3 is an inducible antimicrobial peptide expressed in the epithelia of multiple organs

Infect Immun. 1999 Jul;67(7):3542-7. doi: 10.1128/IAI.67.7.3542-3547.1999.


One component of host defense at mucosal surfaces is epithelium-derived peptides with antimicrobial activity called defensins. We describe in this report the isolation and characterization of a murine homologue of human beta-defensin 2 (hBD-2) called mouse beta-defensin 3 (mBD-3). The predicted amino acid sequence shows the hallmark features of other known epithelial defensins, including the ordered array of six cysteine residues. Analysis of a genomic clone of mBD-3 revealed two exons separated by a 1.7-kb intron. The mBD-3 gene is localized at the proximal portion of chromosome 8, the site where genes for mouse alpha- and beta-defensins are found. Under basal condition, mBD-3 transcripts were detected at low levels in epithelial cells of surface organs, such as the intestine and lung. After instillation of Pseudomonas aeruginosa PAO1 into mouse airways, mBD-3-specific mRNA was upregulated significantly not only in large airways but also in the small bowel and liver. Recombinant mBD-3 peptide, produced from a baculovirus expression system, showed antimicrobial activity against P. aeruginosa PAO1 (MIC of 8 micrograms/ml) and Escherichia coli D31 (MIC of 16 micrograms/ml) in a salt-dependent manner. This study demonstrates that a murine homologue of hBD-2 is present in the respiratory system and other mucosal surfaces. These similarities between murine and human host defense apparatus provide further impetus to evaluate the mouse as a model for studying the human innate host defense system.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Anti-Infective Agents / immunology
  • Base Sequence
  • Defensins
  • Epithelial Cells / immunology*
  • Epithelial Cells / metabolism
  • Epithelial Cells / microbiology
  • Escherichia coli Infections / immunology*
  • Gene Expression Regulation / immunology
  • Humans
  • Immunity, Innate
  • Mice
  • Molecular Sequence Data
  • Organ Specificity
  • Protein Biosynthesis*
  • Proteins / genetics
  • Proteins / immunology*
  • Pseudomonas Infections / immunology*
  • Sequence Alignment


  • Anti-Infective Agents
  • Defensins
  • Proteins

Associated data

  • GENBANK/AF092929
  • GENBANK/AF093245