The human body expresses over 100 host defense peptides and proteins (antimicrobial
peptides, AMPs). The compounds are produced by tissues and mucosal surfaces, e.g.
skin, the digestive and urinary tract, the ocular surface and neutrophils, and are believed to
play a crucial role in defense from microbial infection. They are considered to protect the human
body against microbial infections due to their antimicrobial and immunomodulatory activities.
As well as having strong antimicrobial activity towards a broad spectrum of microorganisms,
AMPs have been found to interact with neutrophils, monocytes and T-cells and
promote the production of cytokines. They also neutralize the action of lipopolysaccharide
(LPS) and play a crucial role in wound healing processes.
In response to the microbial stimuli the AMPs are released in order to fight the infection,
however there are several microorganisms evading the human immune system by downregulation
of AMPs. Decreased or elevated expression of AMPs is associated also with several
non-infectious diseases. Despite numerous studies conducted in the field of AMPs over the
last few decades, their exact role in physiological and pathological processes remains to be
explained. In this paper, we review the most significant human AMPs and their potential roles
in maintaining human homeostasis as well as in pathological processes.