Peptide directorySkin, immune & repair

Human beta-defensin 1

The always-on defensin of skin, kidney and every lining.

Where it comes from

Made in
Epithelial cells of skin, airway, kidney tubules, gut and genital tract, made all the time
Sent out by
Constant, not induced by infection
Acts on
  • Gram-negative bacteria
  • Candida and anaerobes, once its disulfide bonds are reduced
  • Dendritic cells

What it does

  • A standing defence on surfaces
  • Far more potent against anaerobes and fungi in the reduced form the gut keeps it in
  • Attracts immune cells through CCR6

In medicine

  • No medicine; variants in DEFB1 have been studied in asthma, HIV transmission and periodontitis without a settled answer
  • Expression is lost in most clear cell kidney cancers and in many prostate cancers, and putting the gene back into kidney cancer cells makes them die 3

Beyond the body’s own use

  • The oxidised peptide is nearly inert. Reducing its three disulfide bonds, as the gut does with thioredoxin, turns it into a potent killer of anaerobes and Candida, which rewrote what it was thought to be for 2
  • It is studied as a tumour suppressor on chromosome 8p; nothing has reached a trial 3

Sources

  1. Bensch et al., hBD-1: a novel beta-defensin from human plasma, FEBS Letters 1995
  2. Schroeder et al., Reduction of disulphide bonds unmasks the activity of human beta-defensin 1, Nature 2011
  3. Sun et al., Human beta-defensin-1, a potential chromosome 8p tumour suppressor, Cancer Research 2006

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.