Beta-defensin 1 (hBD1)

Beta-defensin 1 is a small, cysteine-rich, cationic peptide encoded by the DEFB1 gene and constitutively expressed by epithelial cells in tissues exposed to the environment, such as the respiratory, urinary, and digestive tracts[3][5][6]. As a member of the β-defensin family, it serves as a key effector molecule of the innate immune system, exerting broad-spectrum antimicrobial activity against bacteria (especially Gram-negative), fungi, and enveloped viruses[1][3][8]. It also plays immunomodulatory roles by chemoattracting immune cells—such as dendritic cells—through interactions with the CCR6 receptor, and by modulating their survival and differentiation[1][4]. Expression of hBD1 is commonly reduced in several cancers, and its loss has been linked to increased tumor proliferation, suggesting a tumor suppressor function[3][4]. Beta-defensin 1 acts via membrane disruption and, uniquely, its reduced (non–disulfide-bonded) form entraps bacteria in net-like structures, adding to its host defense mechanisms, and is tightly regulated by cellular signaling pathways including EGFR/MYC[3][7]. It is not currently a direct drug target but inspires the development of novel antimicrobial agents and immunomodulators[1][8].

Other names

β-defensin 1hBD-1DEFB1 (gene)Human beta-defensin 1

Direct disruption of microbial membranes (permeabilization/lysis); Redox-dependent bacterial entrapment (formation of nets that immobilize bacteria); Chemoattraction via CCR6 activation; Inhibition of cell proliferation and induction of apoptosis in certain tumors