Open AccessImmunomodulating and anti‐infective effects of a novel strain of L actobacillus paracasei that strongly induces interleukin‐12
Author(s) -
Iwabuchi Noriyuki,
Yonezawa Sumiko,
Odamaki Toshitaka,
Yaeshima Tomoko,
Iwatsuki Keiji,
Xiao JinZhong
Publication year - 2012
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1111/j.1574-695x.2012.01003.x
Subject(s) - biology , lactobacillus paracasei , splenocyte , microbiology and biotechnology , interleukin 12 , immunity , interferon , in vitro , intracellular parasite , spleen , immunology , lactobacillus rhamnosus , innate immune system , interleukin , lactobacillus , cytokine , immune system , bacteria , cytotoxic t cell , biochemistry , genetics
Several studies have demonstrated that some strains of lactic acid bacteria ( LAB ) can elicit natural killer ( NK ) cell activities via interleukin‐12 ( IL ‐12) induction and protect against influenza virus ( IFV ) infection. LAB strains that strongly induce IL ‐12 are expected to be effective in protecting against IFV infection. In this study, we screened 85 strains for their ability to induce the in vitro production of IL ‐12, and L actobacillus paracasei M o L ac‐1 most strongly induced IL ‐12. To examine the immunomodulating effects of M o L ac‐1, we have performed in vitro studies using murine splenocytes. Heat‐killed M o L ac‐1 cells induced IL ‐12 and interferon‐γ ( IFN ‐γ) production by murine splenocytes. Experiments using splenocytes depleted of various cell populations indicated that macrophages might be a major source of M o L ac‐1‐induced IL ‐12 secretion. Intracellular staining of IFN ‐γ suggested that M o L ac‐1 activated NK cells and induced IFN ‐γ production by NK cells in vitro . Oral administration of heat‐killed M o L ac‐1 increased the proportion of NK cells in spleen, and ameliorated the symptoms of IFV infection in mice. These results suggest that heat‐killed M o L ac‐1 has the potential to modulate innate immunity and is useful for alleviation of the symptoms of IFV infection.