Oral administration of heat-killed Lactobacillus plantarum L-137 enhances protection against influenza virus infection by stimulation of type I interferon production in mice

Int Immunopharmacol. 2009 Aug;9(9):1122-5. doi: 10.1016/j.intimp.2009.04.015. Epub 2009 May 3.


We have previously reported that heat-killed Lactobacillus plantarum L-137 (HK-LP) stimulates macrophage/dendritic cells to produce T helper (Th) 1-related cytokines in vitro and in vivo in mice. We here examined the effect of oral administration of HK-LP on protection against influenza virus infection in mice. C57BL/6 mice were orally given HK-LP from day -7 to 7 and intranasally infected with influenza virus A/FM/1/47 (H1N1, a mouse-adapted strain) at 100 pfu on day 0. The survival time was significantly prolonged in mice treated with HK-LP than that in mice treated with PBS as controls. The viral titers in the lung were significantly lower in mice treated with HK-LP than controls at the early stage after influenza virus infection. An appreciable level of interferon (IFN)-beta was detected in the serum of mice treated with HK-LP, while no IFN-beta was detected in controls after influenza infection. Our results suggest that HK-LP, a potent IFN-beta inducer, is useful for prevention against influenza infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Female
  • Influenza Vaccines / administration & dosage
  • Interferon Type I / blood*
  • Lactobacillus plantarum / immunology*
  • Lung / pathology
  • Lung / virology
  • Mice
  • Mice, Inbred C57BL
  • Orthomyxoviridae / immunology*
  • Orthomyxoviridae Infections / blood
  • Orthomyxoviridae Infections / immunology*
  • Orthomyxoviridae Infections / prevention & control*
  • Probiotics / administration & dosage
  • Vaccines, Inactivated / administration & dosage
  • Viral Load


  • Influenza Vaccines
  • Interferon Type I
  • Vaccines, Inactivated