Activity of Antimicrobial Peptide; Cathelicidin, on Bacterial Infection

Abstract

Antimicrobial peptide is an effector molecule from the natural immune system which plays a central role in defense as an antimicrobial. Cathelicidin is one of the antimicrobial peptides. Human only has one cathelicidin antimicrobial peptide called LL-37 or hCAP18. The detailed mechanism on CAMP (Cathelicidin Antimicrobial Peptide) gene regulation is still unknown, however, cathelicidin is found to have upregulation when there is bacterial infection. The most effective expression inducer of CAMP gene is 1,25-dihydroxyvitamin D₃ (1,25(OH)₂ D₃), which is the active form of vitamin D. Vitamin D mediates cathelicidin synthesis through the expression of Vitamin D Receptor (VDR), then the interaction activates CAMP gene to express cathelicidin. The work mechanisms of cathelicidin against bacterial infection include damaging the bacterial cell membrane, inducing autophagy process of macrophage cell, neutralizing LPS produced by bacteria, and chemotactic activities of PMNs, monocytes and lymphocytes.