In vitro study of the effect of a probiotic bacterium Lactobacillus rhamnosus against herpes simplex virus type 1

Braz J Infect Dis. 2012 Mar-Apr;16(2):129-35. doi: 10.1016/s1413-8670(12)70293-3.


Background: Due to the emergence of drug resistance in herpes simplex virus type 1 (HSV-1), researchers are trying to find other methods for treating herpes simplex virus type 1 infections. Probiotic bacteria are effective in macrophage activation and may have antiviral activities.

Objective: This study aimed at verifying the direct effect of Lactobacillus rhamnosus, a probiotic bacterium, in comparison with Escherichia coli, a non-probiotic one, on HSV-1 infection, and determining its effect on macrophage activation for in vitro elimination of HSV-1 infection.

Methods: The above bacteria were introduced into HSV-1 infected Vero cells, and their effects were examined using both MTT and plaque assay. To determine macrophage activation against in vitro HSV-1 infection, J774 cells were exposed to these bacteria; then, macrophage viability was examined with the MTT method, and tumor necrosis factor alpha (TNF-α), interferon-gamma (IFN-γ), and nitric oxide (NO) assessments were performed using the ELISA method.

Results: A significant increased viability of macrophages was observed (p < 0.05) in the presence of Lactobacillus rhamnosus before and after HSV-1 infection when compared with Escherichia coli as a non-probiotic bacterium. However, tumor necrosis factor α concentration produced by Escherichia coli-treated J774 cells was significantly higher than Lactobacillus rhamnosus-treated J774 cells (p < 0.05). interferon-gamma and NO production were not different in the groups treated with Escherichia coli or with Lactobacillus rhamnosus.

Conclusion: The results of this study indicate that Lactobacillus rhamnosus enhances macrophage viability for HSV-1 elimination and activation against HSV-1 more effectively, when compared with non-probiotic Escherichia coli. it also seems that receptor occupation of macrophage sites decreases HSV-1 infectivity by both of the studied bacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Escherichia coli / physiology*
  • Herpesvirus 1, Human*
  • Humans
  • Interferon-gamma / analysis
  • Lacticaseibacillus rhamnosus / chemistry*
  • Lacticaseibacillus rhamnosus / physiology
  • Macrophage Activation / drug effects
  • Nitric Oxide / analysis
  • Probiotics / pharmacology*
  • Tumor Necrosis Factor-alpha / analysis
  • Virus Replication / drug effects


  • Tumor Necrosis Factor-alpha
  • Nitric Oxide
  • Interferon-gamma