Beta-defensin 103

experimental

Also known as: Beta-defensin 3, Defensin, beta 103, Defensin-like protein, DEFB103A, DEFB103B, P81534

Beta-defensin 103 (DEFB103A/B), also known as beta-defensin 3, is an antimicrobial peptide primarily expressed in epithelial tissues. Its mechanism of action involves disruption of microbial membranes through electrostatic interactions, leading to pore formation and cell lysis. It exhibits broad-spectrum antimicrobial activity against Gram-positive bacteria (e.g., *Staphylococcus aureus*, *Streptococcus pyogenes*), Gram-negative bacteria (e.g., *Pseudomonas aeruginosa*, *Escherichia coli*), and the yeast *Candida albicans*. Additionally, it may modulate immune responses by acting as a chemoattractant for immune cells. Key research findings from 12 PubMed references indicate that beta-defensin 103 demonstrates potent in vitro activity against multidrug-resistant strains, including methicillin-resistant *S. aureus* (MRSA). Studies also suggest its role in wound healing and epithelial barrier function, with reduced expression observed in inflammatory skin conditions such as atopic dermatitis. Its salt-sensitive activity and potential synergy with other antimicrobial agents have been explored, though in vivo efficacy remains under investigation. Clinical relevance is currently limited to experimental applications, with no approved therapeutic use. Its potential as a topical antimicrobial agent for skin infections or as an adjunct in chronic wound management is under preclinical evaluation. Challenges include stability, delivery, and cost of synthesis. For research purposes only — not medical advice.

Key data

Category
Immune Modulation
Sequence
MRIHYLLFALLFLFLVPVPGHGGIINTLQKYYCRVRGGRCAVLSCLPKEEQIGKCSTRGRKCCRRKK
Molecular weight
7697 g/mol
Research status
experimental
References
12
Tags
uniprot, 3d-structure, antibiotic, antimicrobial, defensin, direct-protein-sequencing, disulfide-bond, reference-proteome, secreted, signal

Mechanism of action

Exhibits antimicrobial activity against Gram-positive bacteria S.aureus and S.pyogenes, Gram-negative bacteria P.aeruginosa and E.coli and the yeast C.albicans. Kills multiresistant S.aureus and vancomycin-resistant E.faecium. No significant hemolytic activity was observed

Research & studies

Impact of β-defensin 103 (DEFB103) copy number variation on bull sperm parameters and post-insemination uterine gene expression
PloS one · 2025 · PubMed

Low DEFB103 copy number was associated with increased sperm motility across all bulls (p < 0.05).; Sperm from low CN bulls showed higher binding to oviductal epithelium, while high CN increased sperm membrane fluidity in vitro (p < 0.05).; Uterine transcriptomic analysis post-insemination identified 58 differentially expressed genes (FDR < 0.1) involved in sperm migration, immune signaling, and chemotaxis.; DEFB103 CNV may contribute to pregnancy outcomes by affecting both sperm function and the uterine response to bull sperm.

Canine coat color E locus updates: Identification of a new MC1R variant causing 'sable' coat color in English Cocker Spaniels and a proposed update to the E locus dominance hierarchy
Animal genetics · 2024 · PubMed
Evaluation of the effects of chlorhexidine digluconate with and without cBD103 or cCath against multidrug-resistant clinical isolates of Staphylococcus pseudintermedius
Veterinary dermatology · 2022 · PubMed
Exploring Pleiotropic Functions of Canine β-Defensin 103: Nasal Cavity Expression, Antimicrobial Activity, and Melanocortin Receptor Activity
Anatomical record (Hoboken, N.J. : 2007) · 2021 · PubMed

cBD103 is expressed in nasal epithelium, nares, and olfactory regions, but absent in goblet cells.; The G23 mutation does not appreciably change antimicrobial activity against tested microorganisms.; Both cBD103 forms cause membrane blebbing, condensation, and cell wall lysis in E. coli and S. aureus.; cBD103 G23 increases ERK1/2 activation and cAMP via melanocortin-4 receptor as a weak allosteric agonist.

Tissue- and age-dependent expression of the bovine DEFB103 gene and protein
Cell and tissue research · 2016 · PubMed
Transcription of canine toll-like receptor 2, β-defensin 1 and β-defensin 103 in infected atopic skin, non-infected atopic skin, healthy skin and the CPEK cell line
Veterinary microbiology · 2013 · PubMed
Signature of balancing selection at the MC1R gene in Kunming dog populations
PloS one · 2013 · PubMed
Activity, expression and genetic variation of canine β-defensin 103: a multifunctional antimicrobial peptide in the skin of domestic dogs
Journal of innate immunity · 2012 · PubMed

CBD103 gene has a 3-basepair deletion allele and copy-number variation (2-4 copies per diploid genome).; Golden and Labrador retrievers uniquely encode the CBD103 G23 variant allele.; Recombinant CBD103 and its variant show potent antimicrobial activity against methicillin-resistant Staphylococcus pseudintermedius.; CBD103 expression in atopic dermatitis skin is similar to healthy controls, unlike reduced human β-defensin 3 expression.

Frequently asked questions

What is Beta-defensin 103?

Beta-defensin 103 (DEFB103A/B), also known as beta-defensin 3, is an antimicrobial peptide primarily expressed in epithelial tissues. Its mechanism of action involves disruption of microbial membranes through electrostatic interactions, leading to pore formation and cell lysis. It exhibits broad-spectrum antimicrobial

How does Beta-defensin 103 work?

Exhibits antimicrobial activity against Gram-positive bacteria S.aureus and S.pyogenes, Gram-negative bacteria P.aeruginosa and E.coli and the yeast C.albicans. Kills multiresistant S.aureus and vancomycin-resistant E.faecium. No significant hemolytic activity was observed

What is the research status of Beta-defensin 103?

Beta-defensin 103 is currently classified as experimental, with 12 research references on record. This is for research purposes only and is not medical advice.

What is the molecular weight of Beta-defensin 103?

Beta-defensin 103 has a molecular weight of approximately 7697 g/mol.

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