Immunomodulatory peptides: new therapeutic horizons for emerging and re-emerging infectious diseases.

The emergence and re-emergence of multi-drug-resistant (MDR) infectious diseases have once again posed a significant global health challenge, largely attributed to the development of bacterial resistance to conventional anti-microbial treatments. To mitigate the risk of drug resistance globally, both antibiotics and immunotherapy are essential. Antimicrobial peptides (AMPs), also referred to as host defense peptides (HDPs), present a promising therapeutic alternative for treating drug-resistant infections due to their various mechanisms of action, which encompass antimicrobial and immunomodulatory effects. Many eukaryotic organisms produce HDPs as a defense mechanism, for example Purothionin from plant, Defensins, Cathelicidins, and Histatins from humans and many such peptides are currently the focus of research because of their antibacterial, antiviral and anti-fungicidal properties. This article offers a comprehensive review of the immunomodulatory activities of HDPs derived from eukaryotic organisms including humans, plants, birds, amphibians, reptiles, and marine species along with their mechanisms of action and therapeutic benefits.