Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:031927 (cytokine)
 144,509 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of bacterial flora on cytokine production from resident peritoneal macrophages was investigated in the mouse. The production of IL-1, IL-6 and TNF-alpha was determined in germ-free, and "conventionalized" mice, as well as in monoxenic mice implanted with either the Gram-negative bacterium E. coli, or the Gram-positive organism Bifidobacterium bifidum. Macrophages from the "conventionalized" mice produced significantly more IL-1 and IL-6 in vitro than those of the germ-free mice. IL-1 and IL-6 production from germ-free mice implanted with E. coli was comparable to that from "conventionalized" mice. However, implantation with Bifidobacterium bifidum did not increase production of these two cytokines above levels observed for macrophages from the germ-free mice. A little TNF-alpha was produced by only the macrophages from the "conventionalized" and monoxenic mice implanted with E. coli. Soon after implantation, the bacterial flora stimulated cytokine production by mouse peritoneal macrophages and our results suggest that Gram negative bacteria are the most efficient stimulus for this production.
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PMID:Influence of intestinal bacterial flora on cytokine (IL-1, IL-6 and TNF-alpha) production by mouse peritoneal macrophages. 831 73

When used in commercial fermented dairy products, bifidobacteria may enhance immunity by stimulating cytokine secretion by leukocytes. To assess whether interaction between bifidobacteria and leukocytes promote cytokine production, we cultured RAW 264.7 cells (macrophage model) and EL-4.IL-2 thymoma cells (helper T-cell model) in the presence of 14 representative strains of heat-killed bifidobacteria. In unstimulated RAW 264.7 cells, all bifidobacteria induced pronounced increases (up to several hundred-fold) in the production of tumor necrosis factor-alpha compared with that of controls. Interleukin-6 production by unstimulated cells also increased significantly, but less than did tumor necrosis factor-alpha. Upon concurrent stimulation of RAW 264.7 cells with lipopolysaccharide, production of tumor necrosis factor-alpha and interleukin-6 were both enhanced between 1.5- to 5.8-fold and 4.7- to 7.9-fold, respectively, when cultured with 10(8) bifidobacteria/ml. In unstimulated EL-4.IL-2 cells, bifidobacteria had no effect on the production of interleukin-2 or interleukin-5. Upon stimulation of EL-4.IL-2 with phorbol-12-myristate-13-acetate, there were variable increases in interleukin-2 secretion (up to 2.4-fold for 10(6) Bifidobacterium Bf-1/ml) and interleukin-5 secretion (up to 4.6-fold for 10(8) B. adolescentis M101-4). The results indicated that, even when variations among strains were considered, direct interaction of most bifidobacteria with macrophages enhanced cytokine production, but the effects on cytokine production by the T-cell model were less marked. Interestingly, the 4 bifidobacteria strains used commercially for diary foods showed the greatest capacity for cytokine stimulation. The in vitro approaches employed here should be useful in future characterization of the effects of bifidobacteria on gastrointestinal and systemic immunity.
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PMID:Differential cytokine production in clonal macrophage and T-cell lines cultured with bifidobacteria. 940 65

The effects of four commercial strains of Streptococcus thermophilus used in yogurt manufacturing on cytokine production were evaluated by using a macrophage model (RAW 264.7 cells) and a T-helper-cell model (EL4.IL-2 thymoma cells) and compared to immunologically active strains of Lactobacillus bulgaricus, Bifidobacterium adolescentis, and Bifidobacterium bifidum. All cytokines (TNF-alpha and IL-6 in RAW 264.7 cells and IL-2 and IL-5 in EL4.IL-2 cells) were affected by heat-killed S. thermophilus in a strain- and dose-dependent fashion. Organisms of all three genera induced significant increases in IL-6 production by the macrophage line ranging from 31- to 192-fold, with S. thermophilus St 133 showing the greatest activity. The four S. thermophilus strains also strongly induced TNF-alpha production (from 135- to 176-fold). IL-6 and, to a lesser extent, TNF-alpha production were also increased when the macrophages were costimulated with lipopolysaccharide and cells of the three groups of lactic acid bacteria. Upon concurrent stimulation of EL4.IL-2 cells with phorbol 12-myristate-13-acetate, seven of the eight strains displayed significant enhancement of IL-2 and IL-5 production, with S. thermophilus being most effective. Taken together, the S. thermophilus strains stimulated macrophage and T-cell cytokine production to a similar or greater extent than did the species of Bifidobacterium and Lactobacillus. These and previous results lend further support to the contention that lactic acid bacteria, in a concentration-dependent manner, can differentially induce cytokine production in macrophages, but that the effects on T cells required a costimulatory signal and were less remarkable.
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PMID:Stimulation of cytokine production in clonal macrophage and T-cell models by Streptococcus thermophilus: comparison with Bifidobacterium sp. and Lactobacillus bulgaricus. 967 70

Increasing numbers of functional foods and pharmaceutical preparations are being promoted with health claims based on the potential probiotic characteristics of lactic acid bacteria and on their capacity for stimulating the host immune system. However, the specific immune effects of oral administration of these microbes still remains undefined. In this study, we tested the hypothesis that production of immunologic mediators by leukocytes in mice is affected by orally administered lactic acid bacteria. The specific objectives of this study were to evaluate the effects of exposure to eight different lactic acid bacteria in mice on ex vivo cytokine and nitric oxide production in leukocyte cultures. Mice were gavaged with 1 X 10(9) viable bacteria and peritoneal, Peyer's patch and splenic leukocytes were isolated 8 h later. These were cultured for 2 or 5 days in the presence or absence of mitogens and then interleukin (IL)-6, IL-12, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and nitric oxide production was measured. The results revealed that Lactobacillus acidophilus and L. casei potentiated IL-6 and IL-12 production by peritoneal cells whereas L. acidophilus upregulated IFN-gamma and nitric oxide. In contrast, L. helveticus, L. gasseri, L. reuteri, and Bifidobacterium attenuated the production of IL-6, IFN-gamma, and nitric oxide by peritoneal cells. TNF-alpha was not detectable in peritoneal cultures. None of the bacteria altered ex vivo production of cytokines or nitric oxide by Peyer's patch or spleen cell cultures. Taken together, the results suggest that prior oral exposure to lactic acid bacteria could differentially potentiate or attenuate subsequent cytokine and nitric oxide production by peritoneal cells.
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PMID:Ex vivo effects of lactobacilli, streptococci, and bifidobacteria ingestion on cytokine and nitric oxide production in a murine model. 1003 Jun 36

To assess the potential for ingestion of yogurt to modulate immunity, its effects on basal gene expression of cytokines in systemic and mucosal sites were determined in mice. Yogurts were manufactured from pasteurized nonfat dry milk using five commercial starter cultures with or without Bifidobacterium sp. and Lactobacillus acidophilus. Treatment mice were fed the AIN-93G diet mixed 1:1 with unheated yogurt or heat-treated yogurt (wt/wt) for 2 and 4 weeks, and control mice were fed the AIN-93G diet mixed 1:1 (wt/wt) with nonfat dry milk. The viability of the various bacterial groups in unheated yogurts was maintained above 10(6) CFU/g throughout the feeding period. The yogurt-feeding regimens did not significantly affect weight gain. Relative mRNA levels in spleen, mesenteric lymph nodes, or Peyer's patches for the cytokines interferon-gamma, tumor necrosis factor-alpha, interleukin-2, -4, and -6, and the "housekeeping gene" beta2-microglobulin were determined by reverse transcriptase-polymerase chain reaction in conjunction with hybridization analysis. Prolonged feeding of some yogurts decreased expression of several cytokine mRNAs, the depression of tumor necrosis factor-alpha mRNA in the spleen being the most prominent effect. Heat-treated yogurts were more effective in altering cytokine mRNA expression than were unheated yogurts containing viable organisms. Generally, yogurts either had no effect or decreased specific cytokine mRNA in the test organs, regardless of whether they contained Bifidobacterium sp. and L. acidophilus. These results suggest that, in contrast with previous studies in vitro, some yogurt formulations may reduce rather than stimulate basal cytokine expression and that these effects are most prominent in the systemic compartment.
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PMID:Effects of yogurt ingestion on mucosal and systemic cytokine gene expression in the mouse. 1003 Jun 39

Cells from a number of bacterial genera have been shown to possess mitogenic and polyclonal activating properties when cultured with cells of the immune system. Based on previously reported health immune-enhancing effects of fermented dairy products, we tested the potentiating effects of representative lactic acid bacteria and their extracts on leukocyte function. Specifically, the effects of in vitro exposure to heat-killed cells of Bifidobacterium, Lactobacillus acidophilus, L. bulgaricus, L. casei, L. gasseri, L. helveticus, L. reuteri, and Streptococcus thermophilus, their cell walls, and their cytoplasmic extracts on proliferation as well as cytokine and nitric oxide (NO) production were examined in the RAW 264.7 macrophage cell line. A similar strategy was applied to murine cultures composed of peritoneal, spleen, and Peyer's patch cells. Both the cell wall and cytoplasmic fractions of lactic acid bacteria were able to stimulate cloned macrophages to produce significant amounts of tumor necrosis factor-alpha, (interleukin) IL-6, and NO. Pronounced enhancement of IL-6 production by peritoneal cells was observed when cultured with those extracts, whereas, effects were not noted in spleen and Peyer's patch cell cultures from mice. Based on the results, it appears that, as a group, the lactic acid bacteria were capable of stimulating macrophages and possibly other immune cells to produce cytokines and NO, and both their cell walls and cytoplasm contributed to these capacities.
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PMID:Proinflammatory cytokine and nitric oxide induction in murine macrophages by cell wall and cytoplasmic extracts of lactic acid bacteria. 1060 48

Cytokines secreted by human enterocytes play a critical role in mucosal and systemic immunity. Intestinal microorganisms can influence this secretion. In the present study, 30 strains of lactic acid bacteria were characterized for their adhesion to Caco-2 cells and their potential to stimulate proinflammatory cytokine secretion by this cell line. The bacteria adhered in a strain-dependent manner to Caco-2 cells. Contact with lactobacilli did not result in the production of IL-6 or IL-8. A slight IL-6 and IL-8 production by a Caco-2 cell was detected after exposure to 8 of the tested Bifidobacterium strains. No correlation was found between adhesion and cytokine induction among the bacteria tested. This indicates that lactic acid bacteria, even those with strong adhesive properties, are not very likely to trigger an inflammatory response in human enterocytes.
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PMID:Adhesion of lactic acid bacteria to caco-2 cells and their effect on cytokine secretion. 1206 32

The hygiene hypothesis postulates that the prevalence of allergy has increased due to decreased microbial stimulation early in life, leading to delayed maturation of the immune system. The aim of this study was to examine the cytokine pattern produced from cord blood mononuclear cells relative to adult cells after stimulation with bacterial strains from the normal flora. Mononuclear cells from cord and adult blood samples were stimulated with the following bacteria: Bifidobacterium adolescentis, Enterococcus faecalis, Lactobacillus plantarum, Streptococcus mitis, Corynebacterium minutissimum, Clostridium perfringens, Bacteroides vulgatus, Escherichia coli, Pseudomonas aeruginosa, Veillonella parvula, and Neisseria sicca. The levels of interleukin 12 (IL-12), tumor necrosis factor alpha (TNF-alpha), IL-10, and IL-6 were measured by enzyme-linked immunosorbent assay. The TNF-alpha production was also analyzed after blocking CD14, Toll-like receptor 2 (TLR-2), and TLR-4 prior to stimulation with bacteria. The levels of IL-12 and TNF-alpha were similar in cord and adult cells. Gram-positive bacteria induced considerably higher levels of IL-12 and TNF-alpha than gram-negative bacteria in both cord and adult cells. The levels of IL-6 were significantly higher in newborns than in adults, whereas the levels of IL-10 were similar in newborns and adults. Gram-negative and gram-positive bacteria induced similar levels of IL-6 and IL-10 in cord cells. L. plantarum bound or signaled through CD14, TLR-2, and TLR-4, whereas E. coli acted mainly through CD14 and TLR-4. These results indicate that the innate immune response in newborns to commensal bacteria is strong and also suggest that different bacterial strains may have differential effects on the maturation of the immune system of infants.
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PMID:Innate immune responses of human neonatal cells to bacteria from the normal gastrointestinal flora. 1243 43

This study evaluated the cytokine profiles (type 1 or type 2) that are triggered by and modulate endodontic periapical infections in the root canal system of germ-free mice. Microorganisms isolated from two patients with pulpal necrosis were inoculated into two groups of experimental animals: group I (Gemella morbillorum) and group II (Bifidobacterium adolescentis, Fusobacterium nucleatum and Clostridium butyricum). In vitro, G. morbillorum induced type 1 cytokine synthesis, while the modulation processed in vivo seemed to have the opposite effect, with a reduction in the basal levels of IL-12 and IFN-gamma, IL-4-independent down-modulation. In vitro, microorganisms from group II, in poly-infection, induced a reduction of type 1 cytokine levels from day 10 to day 20, which seemed to be modulated via IL-4. In vivo, however, a predominance of the immune response to one species over the others occurred.
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PMID:Cytokine production in response to endodontic infection in germ-free mice. 1248 25

To characterize the ability of bifidobacteria to affect the production of macrophage-derived cytokines, a murine macrophage-like cell line, J774.1, was cultured in the presence of 27 strains of heat-inactivated bifidobacteria. Bifidobacterium adolescentis and B. longum, known as adult-type bifidobacteria, induced significantly more pro-inflammatory cytokine secretion, IL-12 and TNF-alpha, by J774.1 cells, than did the infant-type bifidobacteria, B. bifidum, B. breve, and B. infantis (P<0.01). In contrast, B. adolescentis did not stimulate the production of anti-inflammatory IL-10 from J774.1 cells as the other tested bacteria did. The results suggest that the adult-type bifidobacteria, especially B. adolescentis, may be more potent to amplify but less able to down-regulate the inflammatory response.
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PMID:Stimulation of the secretion of pro-inflammatory cytokines by Bifidobacterium strains. 1251 76


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