Defensin HNP-1

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

Research Dosage Notes

The following reflects doses used in published research studies. This is not medical advice.

No established therapeutic dosing. Research context only.

Amino Acid Sequence

Side Effects & Safety

• Pro-inflammatory at high concentrations
• Cytotoxicity to mammalian cells at very high concentrations

Synergistic Compounds

The following compounds have been studied alongside Defensin HNP-1 for potential complementary or synergistic effects:

Related Peptides

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References & Further Reading

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