Cathelicidin is a member of a family of host defense peptides found in immune cells, epithelial surfaces, and secretory glands throughout the body. Its primary active form, LL-37, is released upon proteolytic processing and exhibits potent broad-spectrum antimicrobial activity against bacteria, fungi, and enveloped viruses. Beyond direct antimicrobial action, cathelicidin plays an important immunomodulatory role — stimulating chemokine production, promoting wound closure, and modulating inflammatory responses. Research has explored its involvement in skin barrier defense, respiratory immunity, and inflammatory disease pathways.