β-Defensin 1 (DEFB1) is a member of the β-defensin family, which is highly expressed by epithelial cells. β-defensins are expressed as the C-terminal portion of precursors and are released by proteolytic cleavage of a signal peptide. β-defensins contain a six-cysteine motif that forms three intra-molecular disulfide bonds. β-defensin 1 is an antimicrobial peptide implicated in the resistance of epithelial surfaces to microbial colonization. Defects in β-Defensin-1 contribute to asthma diagnosis, with apparent gender-specific effects in human. β-defensin 1 may also play a role in the pathogenesis of severe sepsis. In addition, β-defensin 1 is associated with induction profiles in gingival keratinocytes.