Human Beta-Defensin 3
Evidence: CAntimicrobial / Innate-Defense Peptides
Evidence Snapshot
What this grade covers
Composite proposed grade: identity/expression B; organism-specific antimicrobial activity (named organisms only) B-; Burkholderia-species activity CONTESTED/D (directly conflicting sources, not resolvable to a single grade); immunomodulatory activity C; CCR6 context B (receptor-context only); paralog/population-genetic context C.
Regulatory Context
Endogenous human peptide; no native hBD-3 drug product approval record identified in this review.
Research Takeaway
Human beta-defensin 3 (hBD-3) is a ~45-residue, three-disulfide-bond peptide encoded by DEFB103A, independently isolated by two research groups from psoriatic skin and via genomic/bioinformatic screening.
Evidence boundary: DEFB103A/DEFB103B paralog-provenance ambiguity exists at the genomic level.
See all 6 evidence claims →Quick Summary
Human beta-defensin 3 (hBD-3) is an inducible human epithelial antimicrobial peptide with documented bactericidal activity against a specific, named set of organisms including multidrug-resistant Staphylococcus aureus. Its activity against Burkholderia species is directly contested in the published literature -- one study reports activity, an independent study reports high resistance -- and this page presents both findings rather than favoring one.
Mechanism & Research Overview
Human beta-defensin 3 (hBD-3) is an inducible human epithelial antimicrobial peptide with documented bactericidal activity against a specific, named set of organisms including multidrug-resistant Staphylococcus aureus. Its activity against Burkholderia species is directly contested in the published literature -- one study reports activity, an independent study reports high resistance -- and this page presents both findings rather than favoring one.
Evidence Claims
Individual scientific statements drawn from the sources cited below, each shown with the specific evidence boundary that statement does not establish.
Supported
Human beta-defensin 3 (hBD-3) is a ~45-residue, three-disulfide-bond peptide encoded by DEFB103A, independently isolated by two research groups from psoriatic skin and via genomic/bioinformatic screening.
Does not establish
Evidence boundary: DEFB103A/DEFB103B paralog-provenance ambiguity exists at the genomic level.
Sources: Isolation and characterization of human beta-defensin-3, a novel human inducible peptide antibiotic; Identification of a novel, multifunctional beta-defensin (human beta-defensin 3) with specific antimicrobial activity
Supported
hBD-3 shows salt-insensitive bactericidal activity against Staphylococcus aureus (including multidrug-resistant strains), Enterococcus faecium, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter baumannii in vitro.
Does not establish
Evidence boundary: Organism list is EXACT and EXHAUSTIVE for these sources. No other organism, including Burkholderia, may be added to this claim without a separately frozen source.
Sources: Isolation and characterization of human beta-defensin-3, a novel human inducible peptide antibiotic; In Vitro Bactericidal Activity of Human Beta-Defensin 3 against Multidrug-Resistant Nosocomial Strains
Supported
The scientific literature is divided on hBD-3's activity against Burkholderia species: one study reports hBD-3 activity relevant to Burkholderia cepacia, while an independent study from an overlapping research group reports that Burkholderia is highly resistant to hBD-3.
Does not establish
Evidence boundary: UNRESOLVED CONTRADICTION. Must not imply hBD-3 is definitively active or definitively inactive against Burkholderia. Both sources must always be cited together.
Sources: Identification of a novel, multifunctional beta-defensin (human beta-defensin 3) with specific antimicrobial activity; Burkholderia Is Highly Resistant to Human Beta-Defensin 3
Supported
hBD-3 induces monocyte chemoattraction and ion-channel activity in membrane-based assays, a function distinct from its direct antimicrobial killing activity.
Does not establish
Evidence boundary: Single source; must remain a separate claim family from direct-killing claims, not used to strengthen them.
Supported
hBD-3 shares the CCR6-mediated dendritic-cell/T-cell chemotactic mechanism reported for beta-defensins generally.
Does not establish
Evidence boundary: SHARED with hBD-2; evidence transfer between hBD-2 and hBD-3 based on this shared receptor is prohibited for antimicrobial-efficacy purposes.
Sources: Beta-defensins: linking innate and adaptive immunity through dendritic and T cell CCR6
Supported
The DEFB103 gene locus shows worldwide copy-number variation, with evidence of recent selection for a high-expressing gene copy in East Asian populations.
Does not establish
Evidence boundary: Genomic-association finding only; protein-level antimicrobial activity was not measured in this study.
Safety & Evidence Limitations
Considerations reported in the sources cited on this page — not a complete list of every possible risk, and not medical advice.
Safety Consideration
Independent primary studies directly conflict on hBD-3's activity against Burkholderia species; this must be disclosed as an unresolved disagreement, never resolved in either direction.Safety Consideration
The organism list supported by the frozen evidence is limited to those specifically named in the sources; broader 'broad-spectrum' language is not supported.Safety Consideration
hBD-3's monocyte-chemoattraction/ion-channel activity must not be merged into a single undifferentiated 'host defense' narrative with its direct-killing activity.
Research Areas Being Studied
Research areas discussed on this page reflect the Antimicrobial / Innate-Defense Peptides category and the sources cited below.
Findings Reported in Studies
Educational summary only — reported in cited studies, not a claim of proven benefit.
- A worldwide analysis of beta-defensin copy number variation suggests recent selection of a high-expressing DEFB103 gene copy in East Asia (2011):
- In Vitro Bactericidal Activity of Human Beta-Defensin 3 against Multidrug-Resistant Nosocomial Strains (2006):
- Burkholderia Is Highly Resistant to Human Beta-Defensin 3 (2003):
- Identification of a novel, multifunctional beta-defensin (human beta-defensin 3) with specific antimicrobial activity (2001):
- Isolation and characterization of human beta-defensin-3, a novel human inducible peptide antibiotic (2001):
- Beta-defensins: linking innate and adaptive immunity through dendritic and T cell CCR6 (1999):
Study Tables by Evidence Type
Human Studies & Clinical Data
| Title | Year | Population / Model | Dose / Duration / Finding | Safety Notes | Source |
|---|---|---|---|---|---|
| A worldwide analysis of beta-defensin copy number variation suggests recent selection of a high-expressing DEFB103 gene copy in East Asia | 2011 | worldwide human population genetic cohorts | The DEFB103 gene locus shows worldwide copy-number variation, with evidence of recent selection for a high-expressing gene copy in East Asian populations. | ||
| In Vitro Bactericidal Activity of Human Beta-Defensin 3 against Multidrug-Resistant Nosocomial Strains | 2006 | in vitro bactericidal/time-kill assay against clinical multidrug-resistant bacterial isolates (S. aureus, E. faecium, P. aeruginosa, S. maltophilia, A. baumannii; 6 strains each) | hBD-3 shows bactericidal activity against multidrug-resistant clinical isolates of S. aureus, E. faecium, P. aeruginosa, S. maltophilia, and A. baumannii. | ||
| Burkholderia Is Highly Resistant to Human Beta-Defensin 3 | 2003 | human hBD-3 peptide vs. clinical Burkholderia isolates, in vitro | Burkholderia species were found to be highly resistant to hBD-3. | ||
| Identification of a novel, multifunctional beta-defensin (human beta-defensin 3) with specific antimicrobial activity | 2001 | synthetic hBD-3; in vitro bactericidal/membrane assays | hBD-3 shows antimicrobial activity against named organisms including activity relevant to Burkholderia cepacia (CONTESTED, see PMID 12709350); separately shows monocyte chemoattraction and ion-channel activity. | ||
| Isolation and characterization of human beta-defensin-3, a novel human inducible peptide antibiotic | 2001 | human psoriatic skin scale / keratinocytes; in vitro bactericidal assay | hBD-3 was isolated from psoriatic skin and shows salt-insensitive antimicrobial activity against multiple organisms tested, including multidrug-resistant S. aureus. | ||
| Beta-defensins: linking innate and adaptive immunity through dendritic and T cell CCR6 | 1999 | human/transfected cell lines (CCR6) | Human beta-defensins are chemotactic for immature dendritic cells and memory T cells via CCR6. |
Animal / Cell / Preclinical Data
No Animal / Cell / Preclinical Data Listed Yet
This section will be updated as sources are added.
Regulatory Documents & Official Trial Registries
No Regulatory Documents & Official Trial Registries Listed Yet
This section will be updated as sources are added.
Anecdotal Reported Patterns — Not Medical Advice
Anecdotal Reported Patterns — Not Medical Advice
Reported dosing patterns are included for educational context only. They are self-reported, unverified, not medical advice, and not instructions for human use. Community-submitted patterns are not yet available in this Phase 1 prototype; this section is a placeholder reserved for moderated, aggregated community data.
Lab Markers to Discuss With a Clinician
Educational topics only — not self-monitoring instructions.
FAQ
Disclaimer
Educational information only. This page summarizes published research on endogenous human beta-defensin 3, including an unresolved scientific disagreement in the primary literature, and does not constitute medical advice, a treatment recommendation, or dosing guidance for any related substance.
Educational use only. This content is provided for informational and research-summary purposes only. It is not medical advice, not a treatment recommendation, not a dosing guide, and not a substitute for care from a licensed medical professional. Nothing here is intended to diagnose, treat, cure, prevent, or mitigate disease. Reported dosing patterns, when shown elsewhere on the site, must be labeled either as Study / Trial Dosing or Anecdotal Reported Patterns — Not Medical Advice. Community reports are self-reported, unverified, and not scientific proof.
Community-reported experiences, once enabled, must be displayed only as moderated, anonymized, or aggregated data. They are anecdotal, self-reported, unverified, and should never be presented as proof of safety, efficacy, or expected results.
Content status: Published. Last updated 2026-08-29.
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