What Is Defensins? Benefits, Research & Safety

Defensins were first identified in rabbit neutrophils by Robert Lehrer and colleagues in the early 1980s. The term "defensin" was coined to reflect their role in host defence. Human neutrophil peptides (HNP-1, HNP-2, HNP-3) were subsequently isolated and characterised. The discovery of beta-defensins came later, with HBD-1 identified in 1995 from human blood plasma and HBD-2 discovered in 1997 from psoriatic skin. This expanded the understanding of defensins from primarily neutrophil-stored to broadly expressed on epithelial surfaces. Research in the 2000s revealed the immunomodulatory functions of defensins beyond direct antimicrobial killing. Studies showed they acted as chemoattractants for dendritic cells and T cells, bridging innate and adaptive immunity. The connection between defensin deficiency and Crohn's disease was established by Wehkamp and colleagues, who showed reduced Paneth cell alpha-defensin expression in ileal Crohn's disease, suggesting a role in the pathogenesis of inflammatory bowel disease. Synthetic defensin analogues and defensin-inspired antimicrobials continue to be developed as potential treatments for antibiotic-resistant infections.