Beta-defensin 4A (DEFB4A)

Beta-defensin 4A is a small cationic antimicrobial peptide belonging to the defensin family. It is primarily expressed by epithelial cells and plays an important role in the innate immune response. Beta-defensin 4A exhibits potent antimicrobial activity against both Gram-negative and Gram-positive bacteria—most notably against Gram-negative species—and also has antifungal properties. Its mechanism involves binding to negatively charged microbial membranes via its positive charge, leading to increased membrane permeability and microbial lysis[1][3]. Beyond its direct microbicidal action, beta-defensin 4A can modulate inflammatory responses by inhibiting pro-inflammatory cytokines and may influence cellular differentiation processes. It has been implicated in host defense at mucosal surfaces such as the respiratory tract, skin, urinary tract, and oral cavity. While not currently targeted by any approved therapeutics or used clinically as a biomarker on its own, it remains an area of interest for research into novel anti-infective agents due to its broad-spectrum antimicrobial properties[1][3][6].

Other names

Human beta-defensin 4HBD-4Defensin, beta 104A (DEFB104A) [sometimes used interchangeably in literature]Beta-defensin 2 (in some older or non-human studies, but this is not strictly correct for human DEFB4A)