LL-37 as a Bioactive Peptide with Multifocal Mechanisms of Action

LL-37 has attracted significant research attention as a multifunctional antimicrobial peptide which is implicated in a broad spectrum of activities. It is the only human cathelicidin and represents a key molecule in host defense. Hence, it is described as possessing antimicrobial activity against a wide range of pathogens, including Gram-negative and Gram-positive bacteria, numerous viral species, and various fungi. Though it is widely recognized for its direct antimicrobial activity, it is a multifaceted immunomodulatory and tissue-protective molecule. Beyond host defense, LL-37 actively regulates inflammatory signaling, cellular interactions within the immune system, and mechanisms of tissue repair. Its ability to fine-tune immune responses and simultaneous regeneration highlights its dual role in inflammation control and wound healing. These pleiotropic functions place LL-37 in the spotlight between innate immunity and tissue homeostasis. This review aims to compile LL-37’s antimicrobial and immunomodulatory activities and highlight its wide range of potential clinical applications.