hBD3

Human beta-defensin 3 (hBD-3) is a small, cationic antimicrobial peptide that belongs to the defensin family and contributes to the innate immune defense of epithelial surfaces. The mature peptide is produced by epithelial cells in the skin, oral cavity, respiratory tract, and other mucosal tissues. In humans, hBD-3 is encoded by the DEFB103A gene as part of a broader defensin gene cluster.

Structurally, hBD-3 is a cysteine-rich peptide that forms a characteristic beta-defensin fold stabilized by three intramolecular disulfide bonds. It is synthesized as a larger precursor and processed to a shorter, active form. The peptide exhibits broad-spectrum antimicrobial activity, effective against many bacteria, fungi, and some viruses, contributing to barrier defense and microbial control at mucosal surfaces.

Beyond direct antimicrobial effects, hBD-3 has immunomodulatory properties. It acts as a chemoattractant for CCR6-expressing immune cells, including immature dendritic cells and memory T cells, and can influence cytokine production by various immune cell types. Expression of hBD-3 is upregulated in response to inflammatory signals and microbial components, helping to tailor the local immune response.

Clinical and research interest in hBD-3 centers on its potential as a therapeutic agent or adjuvant, leveraging its antimicrobial and immunomodulatory activities. Ongoing studies examine its roles in health and disease, including its contribution to host defense at epithelial barriers and its involvement in inflammatory conditions.