Direct Antimicrobial Activity of IFN-?.

ABSTRACT: Type I IFNs are a cytokine family essential for antiviral defense. More recently, type I IFNs were shown to be important during bacterial infections. In this article, we show that, in addition to known cytokine functions, IFN-? is antimicrobial. Parts of the IFN-? molecular surface (especially helix 4) are cationic and amphipathic, both classic characteristics of antimicrobial peptides, and we observed that IFN-? can directly kill Staphylococcus aureus Further, a mutant S. aureus that is more sensitive to antimicrobial peptides was killed more efficiently by IFN-? than was the wild-type S. aureus, and immunoblotting showed that IFN-? interacts with the bacterial cell surface. To determine whether specific parts of IFN-? are antimicrobial, we synthesized IFN-? helix 4 and found that it is sufficient to permeate model prokaryotic membranes using synchrotron x-ray diffraction and that it is sufficient to kill S. aureus These results suggest that, in addition to its well-known signaling activity, IFN-? may be directly antimicrobial and be part of a growing family of cytokines and chemokines, called kinocidins, that also have antimicrobial properties.

SUBMITTER: Kaplan A 

PROVIDER: S-EPMC5469413 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature