Peptide directorySkin, immune & repair

Human beta-defensin 2

The defensin the skin makes when it is infected or inflamed.

Where it comes from

Made in
Keratinocytes, airway and gut epithelium, induced rather than constant
Sent out by
Bacteria, IL-1 and IL-17 switch it on within hours; the psoriasis plaque makes a great deal
Acts on
  • Gram-negative bacteria, Pseudomonas above all
  • Candida
  • Immune cells

What it does

  • Kills Gram-negative bacteria and yeast at the surface
  • Calls in memory T cells and dendritic cells
  • High in psoriasis, low in atopic dermatitis, which may be why eczema gets infected and psoriasis does not

In medicine

  • Blood hBD-2 tracks psoriasis activity in research
  • No medicine. People with psoriasis carry more copies of the DEFB4 gene pair, one of the few genetic links between a disease and the amount of an antimicrobial peptide a person makes 3

Beyond the body’s own use

  • Recombinant hBD-2 given by injection calmed three different mouse models of colitis about as well as anti-TNF or steroids, and it worked through dendritic cells rather than by killing bacteria 2
  • That is the current reason to study it: a defensin as an anti-inflammatory rather than an antibiotic. No human trial has followed

Sources

  1. Harder et al., A peptide antibiotic from human skin, Nature 1997
  2. Koeninger et al., Human beta-defensin 2 as treatment for experimental colitis, Frontiers in Immunology 2020
  3. Hollox et al., Psoriasis is associated with increased beta-defensin genomic copy number, Nature Genetics 2008

This card describes what a medicine is for and what the evidence says; it recommends nothing. Talk to your clinician about anything you read here.