Defensin HNP-1
Also known as: Human Neutrophil Peptide-1, Alpha-Defensin 1, DEFA1
Overview
HNP-1 (Human Neutrophil Peptide-1) is a 30-amino acid cationic alpha-defensin stored in the azurophilic granules of human neutrophils and released during phagocytosis and degranulation. It is one of the most abundant antimicrobial peptides in human blood, acting as a rapid-response innate immune effector against bacteria, fungi, and enveloped viruses. Alpha-defensins also modulate adaptive immunity by recruiting dendritic cells and T lymphocytes, bridging innate and adaptive immune responses.
Mechanism of Action
HNP-1 kills microorganisms primarily by disrupting microbial membrane integrity. Its cationic amphipathic structure allows electrostatic binding to negatively charged bacterial membranes, followed by insertion and pore formation via a 'barrel-stave' or 'carpet' mechanism. This causes membrane depolarization, leakage of cellular contents, and cell death. HNP-1 also inhibits viral fusion (HIV gp120), activates complement, and acts as a chemokine for monocytes and T cells via FPRL1 receptor interactions.
Potential Benefits
- Broad-spectrum antibacterial activity (gram-positive and gram-negative)
- Antifungal activity against Candida species
- Antiviral activity including HIV-1 entry inhibition
- Innate immune bridge to adaptive immunity via T-cell recruitment
- Anti-biofilm activity
- Template for synthetic antimicrobial peptide drug design
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Beginner | Research tool only — not a consumer peptide |
| Intermediate | N/A |
| Advanced | N/A |
| Cycle Duration | N/A |
Endogenous neutrophil α-defensin. Primarily studied as research tool and biomarker.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Topical / Local (research) Variable
Antimicrobial research applications.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Defensin HNP-1:
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Storage | Refrigerate at 2-8°C after reconstitution. Do not freeze reconstituted solution. |
|---|
Typical vial sizes: 0.1-1 mg (research). Add bac water slowly down the side of the vial, swirl gently — do not shake. Use insulin syringe for precise dosing.
Need exact syringe measurements?
Amino Acid Sequence
Ala-Cys-Tyr-Cys-Arg-Ile-Pro-Ala-Cys-Ile-Ala-Gly-Glu-Arg-Arg-Tyr-Gly-Thr-Cys-Ile-Tyr-Gln-Gly-Arg-Leu-Trp-Ala-Phe-Cys-Cys (with three intramolecular disulfide bonds)
Side Effects & Safety
- Pro-inflammatory at high concentrations
- Cytotoxicity to mammalian cells at very high concentrations
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
Pharmacokinetics
| Half-Life | Not well characterized for this peptide; consult primary literature |
|---|---|
| Storage | Store lyophilized peptide at -20°C (long-term) or 2-8°C (short-term, under 30 days). Reconstituted: refrigerate at 2-8°C and use within 28-30 days. Protect from light. Do not freeze reconstituted solution. |
Synergistic Compounds
The following compounds have been studied alongside Defensin HNP-1 for potential complementary or synergistic effects:
Learn More
References & Further Reading
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