November 2, 2020

Frog peptides as anti-HIV microbicides

Peptides derived from the antimicrobial peptides secreted by frogs could function as microbicides to limit HIV transmission, while sparing protective vaginal bacteria.

HIV/AIDS continues to cause significant worldwide morbidity and mortality. Additional measures to reduce HIV transmission are needed, and one possibility is the development of low-cost antiviral microbicides. 

Louise Rollins-Smith, PhD, and colleagues previously demonstrated that caerin 1 antimicrobial peptides (AMPs) — secreted by Australian frogs as part of their immune defenses — inhibit HIV transmission in vitro. 

The researchers have now explored how other natural and synthetic caerin 1 AMPs affect the normal vaginal lactobacilli, which help protect against HIV transmission. They report in the journal Antibiotics that several caerin 1 peptides had limited toxicity for lactobacilli at concentrations that inhibit HIV transmission. 

They also showed that the caerin 1 AMPs inhibited the growth of Neisseria lactamica, a close relative of the bacterium that causes the sexually transmitted infection gonorrhea. 

The findings support the potential of caerin 1 peptides to function as microbicides that limit sexual transmission of HIV and possibly also transmission of pathogenic vaginal bacteria, while sparing protective vaginal bacteria.

This research was funded in part by grants from the U.S. National Science Foundation (IOS-1121758, IOS-1557634).