Antimicrobial and related activities of chemokines

Abstract

Chemokines are now known to play pivotal roles in both innate and acquired immunity primarily through their chemotactic activity for various leukocyte classes and subsets [1]. The family of antimicrobial peptides, also called natural antibiotics, constitutes the important immediate effector molecules against invading microorganisms [2, 3]. Accumulating evidence has revealed that the families of chemokines and antimicrobial peptides have substantially overlapping functions. While a number of antimicrobial peptides are chemotactic for selected classes and subsets of leukocyte [4], many chemokines have a substantial microbicidal activity against a broad spectrum of microorganisms [5–7]. Furthermore, CXCL16, a transmembrane-type chemokine [8, 9], was originally identified as a scavenger receptor termed SR-PSOX (scavenger receptor that binds phosphatidylserine and oxidized lipoprotein) [10]. Subsequently, a number of chemokines have been shown to display a similar binding activity for typical scavenger receptor ligands including oxidized lipoprotein and bacteria [11]. Thus, the family of chemokines may have substantial functional overlaps with the families of antimicrobial peptides and scavenger receptors. The overlapping functions of these distinct molecular families may have an evolutionary basis stemming from an ancient mode of recognition of pathogens and may represent a certain aspect of the pattern recognition of innate immunity.