Stimulation of murine cell-mediated immunity by dietary administration of a cell preparation of <i>Enterococcus faecalis</i> strain KH-2 and its possible activity against tumour development in mice

Abstract

It is well known that dietary lactic acid bacteria (LAB) stimulate cell-mediated immunity such as natural killer (NK) activity in mice. Here, we aimed to assay the immunomodulatory effects of a cell preparation of Enterococcus faecalis strain KH-2 (CPEF). We further evaluated the possibility of antitumour activity caused by CPEF administration, because NK cells actively participate in the prevention of tumour formation. NK cell activity and gene expression of IFN-γ and Perforin 1, which were induced most likely by a synergetic action of their cytotoxic activity, were higher in splenocytes of CPEF-administered mice than they were in control mice. Moreover, unlike those of control mice, the splenocytes of CPEF-administered mice had significantly higher CD28+CD69+/CD4+ and CD28+CD69+/CD8+ ratios that resulted in a survival rate with a tendency toward improvement after 47 days of CPEF administration (p=0.1) in Meth-A fibrosarcoma-bearing mice. In conclusion, we showed that CPEF might be effective in treating Meth-A fibrosarcoma in mice, as it helped increase their survival rate via stimulation of an immune response in splenocytes, which involved systemic cellular immunity processes such as cytotoxic activity, and active T cells.

Topical Administration of Heat-Killed Enterococcus faecalis Strain KH2 Promotes Re-Epithelialization and Granulation Tissue Formation during Skin Wound-Healing

“…Although it remains to be elucidated how the administration of Enterococcus spp. affects the process of wound-healing in skin, treatment with heat-killed E. faecalis strains EC-12 and KH2 was reported to induce the production of inflammatory cytokines by macrophages and to activate natural killer (NK) cells and cytotoxic T cells, respectively [ 13 , 14 ]. In addition, several studies revealed that LAB promote leukocyte function and increase the production of VEGF, one of the most important mediators of angiogenesis [ 13 , 14 , 15 ].…”

A Review of the Effects of Natural Compounds, Medicinal Plants, and Mushrooms on the Gut Microbiota in Colitis and Cancer

“…Enterococcus is a large genus of health-promoting lactic acid bacteria that are common commensals in the human gut. Oral administration of a cell preparation of Enterococcus faecalis strain KH-2 improved the survival rate of Meth-A fibrosarcoma-bearing mice via stimulation of an immune response in splenocytes, which involved systemic cellular immunity processes such as cytotoxic activity and active T cells (Tsukahara et al, 2018). In addition, isoliquiritigenin, a flavonoid isolated from a related species (Glycyrrhiza glabra L.), has also shown antitumor efficacy.…”

Anti-Influenza virus effects of <i>Enterococcus faecalis</i> KH2 and <i>Lactobacillus plantarum</i> SNK12 RNA

“…Lactic acid bacteria (LAB) intake has several major health benefits, such as improvement of fecal microbiota [ 1 , 2 , 3 ] and antibacterial [ 4 , 5 ], anti-allergy [ 6 , 7 ], antitumor [ 8 , 9 ], and antiviral effects [ 10 , 11 , 12 ]. Bacterial cell walls [ 13 ] and extracellular polysaccharides produced by bacteria [ 14 ] have been reported as factors affecting the immune stimulation and biological defense provided by LAB, but no active component has yet been clearly elucidated.…”