Heat-Killed Cells of Lactobacilli Skew the Immune Response Toward T Helper 1 Polarization in Mouse Splenocytes and Dendritic Cell-Treated T Cells

Abstract

It is believed that probiotics play an important role for the health of the host, including modulation of immune responses. Most studies have focused on the immunomodulatory effects of viable cells of lactic acid bacteria; however, we investigated those of heat-killed cells of lactic acid bacteria in this study. We first observed the effects on immune functions via stimulating splenocytes with three heat-killed Lactobacillus strains. Furthermore, we also investigated the effect of mouse dendritic cells (DCs) treated with these heat-killed Lactobacillus strains on T cell responses. The results showed that these Lactobacillus strains were able to stimulate cell proliferation and interleukin (IL)-10, IL-12 p70, and interferon (IFN)-gamma production but not transforming growth factor (TGF)-beta in splenocytes. In addition, these heat-killed Lactobacillus strains also stimulated high-level secretion of IL-12 p70 in DCs and switched T cells to T helper (Th) 1 immune responses, as evidenced by the elevated secretion of IFN-gamma but not IL-5, IL-13, and TGF-beta. These results showed that lactobacilli play a potentially important role in modulating immune responses and allergic reactions.

Establishment of an in Vitro Peyer's Patch Cell Culture System Correlative to in Vivo Study Using Intestine and Screening of Lactic Acid Bacteria Enhancing Intestinal Immunity

“…Furthermore, the heat-killed LAB, G-15 and SN13T, also exhibited the IgA-enhancing effect, suggesting that the result is consistent with those reported previously. 3,9,10) Interestingly, the supernatant fluids from LP28 and 15-1A cultures and the heat-killed LP28 and 15-1A cell mass were ineffective for enhancing IgA production. The heat-unstable substances such as proteins, which are contained in these LAB, might play a role in enhancing the IgA level produced by PPcells.…”

“…Some substances as a cell wall component of LAB may function as immune stimulants in many cases, as shown in reports according to which heat-killed LAB are able to stimulate the immune response. 3,9,10) It has also been reported that the immunomodulatory activity of Bifidobacterium bifidum was not due to components secreted from bacteria. 5) Gram-positive bacteria, such as LAB, contain lipoteichoic acids as a component of the cell walls, which function as major immunostimulatory factors and agonists of the toll-like receptor 2.…”

“…The beneficial functions brought by LAB on gastrointestinal conditions, such as constipation, diarrhea, inflammatory bowel disease, Helicobacter pylori infection, lactose intolerance, and colon cancer, have been reported. 1,2) LAB have also been found to modulate systemic and/or intestinal immune responses, including allergies, [3][4][5][6][7][8][9][10] although their application in medical treatment is still far from possible. It is important to accumulate information about numerous LAB strains to screen the most appropriate and effective LAB for each purpose.…”

Research progress of functional lactic acid bacteria

“…The results of Li Xueping et al [16] showed that lactic acid bacteria can improve the production performance, intestinal health and immune function of broilers. The results of Chuang et al [17] Advances in Engineering Research,volume 129 showed that inactivation of lactic acid bacteria can stimulate cell proliferation and interleukin IL-10, IL-12 P70, interferon IFN-gamma production, and increase the secretion of T cell TH. Beatriz et al [18] showed that the expression of Osp A in lactobacillus plantarum promoted the secretion of cytokine IL-8 in intestinal epithelial cells, and the intestinal immune tolerance was broken by Th1/Th2 cell-mediated immunity.…”

Monoassociation with probiotic Lactobacillus delbrueckii UFV-H2b20 stimulates the immune system and protects germfree mice against Listeria monocytogenes infection

“…It has been reported that some strains of probiotic lactobacilli can induce the production of several antiinflammatory and pro-inflammatory cytokines and other mediators of the immune response such as nitric oxide and reactive oxygen species [6][7][8]. Listeria monocytogenes is a Gram-positive food-borne pathogen that invades the intestinal epithelium, causing a potentially fatal disease, listeriosis.…”