Novel antiviral activity of chemokines

Antimicrobial peptides are a diverse family of small, mostly cationic polypeptides that kill bacteria, fungi and even some enveloped viruses, while chemokines are a group of mostly cationic small proteins that induce directed migration of leukocytes through interactions with a group of seven transmembrane G protein-coupled receptors. Recent studies have shown that antimicrobial peptides and chemokines have substantially overlapping functions. Thus, while some antimicrobial peptides are chemotactic for leukocytes, some chemokines can kill a wide range of bacteria and fungi. Here, we examined a possible direct antiviral activity of chemokines against an enveloped virus HSV-1. Among 22 human chemokines examined, chemokines such as MIP-1 alpha/CCL3, MIP-1 beta/CCL4 and RANTES/CCL5 showed a significant direct antiviral activity against HSV-1. It is intriguing that these chemokines are mostly known to be highly expressed by effector CD8+ T cells. The chemokines with a significant anti-HSV-1 activity commonly bound to HSV-1 virions via envelope glycoprotein gB. Electron microscopy revealed that the chemokines with a significant anti-HSV-1 activity were commonly capable of generating pores in the envelope of HSV-1. Thus, some chemokines have a significant direct antiviral activity against HSV-1 in vitro and may have a potential role in host defense against HSV-1 as a direct antiviral agent.