The antimicrobial activity of interlukin-8 derived peptide is influenced by glucose

Introduction: There is increasing evidence that a wide range of proteins contain concealed functional domains that can be liberated under certain conditions to generate novel bioactivities and add considerable amplification to the human proteome. Further functional complexity is influenced by micro-environmental factors such as the available energy source and divalent ion concentration. Peptides modelled on the C-terminal region of the chemokine interlukin-8 (IL-8) have been shown to possess antimicrobial properties despite the fact that the full length molecule is devoid of this activity.

Aim: The aim of this study was to determine the antimicrobial properties of a 19-mer peptide derived from the C-terminus of IL-8 against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 in both the presence and absence of glucose as an energy source.

Methods: The antimicrobial activity of the 19-mer IL-8 derived peptide was determined against E. coli and S. aureus using an ultra-sensitive double layer radial diffusion assay.

Results: The antimicrobial activity of the IL-8 C-terminal peptide against E. coli was improved in the presence of glucose and its antimicrobial activity against S. aureus was altered from having no activity in the absence of glucose to having a substantial antimicrobial effect in the presence of glucose.

Discussion: The antimicrobial activity of the cryptic C-terminal derived peptide from IL-8 is influenced strongly by the levels of glucose as the carbon source. The potential effect of glucose on the antimicrobial activity of the IL-8 derived peptide against a wide range of micro-organisms warrants further investigation.