Amino Acid Found to Suppress Herpes in Animals

Herpes simplex virus (HSV) infects an individual for their entire life, but likely remains dormant aside from periodic reactivation. While antiviral drugs can shorten reactivation, there are no cures and the mechanisms that drive reactivation are not well-established.

The World Health Organization estimates that more than 500 million individuals have been infected with HSV-2, while two-thirds of the global population has been infected by HSV-1. These infections range in symptoms from lesions on various parts of the body to eye conditions that can lead to blindness.

Reactivation of HSV has been poorly understood and novel treatments are necessary. Findings from a new study published by the Journal of Clinical Investigation suggest that glutamine supplements could be used to suppress the infection.

Previously, the authors found that HSV-specific T cells are crucial for controlling reactivation. The study also showed that activated T cells require increased glutamine, which caused the authors to hypothesize that increasing intake of the amino acid may increase T cell function.

Included in the new study were mice infected with HSV-1 and guinea pigs infected with HSV-2. The animals were randomized to receive an oral glutamine supplement or no treatment.

The authors found that mice treated with glutamine were less likely to experience recurrent HSV-1 activation compared with mice that received no supplementation, according to the study. The investigators reported similar results in the guinea pig models of HSV-2.

When the authors examined host cellular gene expression among mice treated with glutamine, they found multiple genes inducible by interferon gamma (IFN-γ) had a higher response, according to the study. IFN-γ is created by virus-specific T cells in infected nerve tissue, the authors noted.

“We found that glutamine increased the level of several IFN-γ—inducible genes, including Cxcl9, which is critical for controlling genital HSV-2 by mobilizing virus-specific cytotoxic T cells to the nervous system and vagina in mice,” the authors wrote.

Overall, the results suggest that glutamine may reduce HSV reactivation by increasing T cell response, according to the study. Further studies are needed in human cells to determine the efficacy of supplementation.

“There is a clear need for other therapies to suppress oral and genital HSV recurrences,” the authors concluded. “The ability of glutamine to reduce HSV reactivation in 2 different animal models suggests a new approach to reduce reactivation of the virus in humans.”