Complex dietary polysaccharide modulates gut immune function and microbiota,and promotes protection from autoimmune diabetes

The dietary supplement and prebiotic values of β-glucan-rich products have been widely recognized and dietary approaches for modulating autoimmunity have been increasingly explored, we assess the impact of oral administration of high-purity yeast β-glucan (YBG) on gut immune function, microbiota and type 1 diabetes (T1D) using mouse models. Oral administration of this non-digestible complex polysaccharide caused a dectin-1-dependent immune response involving increased expression of interleukin-10 (IL-10), retinaldehyde dehydrogenase (Raldh) and pro-inflammatory cytokines in the gut mucosa. YBG-exposed intestinal dendritic cells induced/expanded primarily Foxp3⁺, IL-10⁺ and IL-17⁺ T cells, ex vivo. Importantly, prolonged oral administration of low-dose YBG at pre-diabetic stage suppressed insulitis and significantly delayed the appearance of T1D in non-obese diabetic (NOD) mice. Further, prolonged treatment with YBG showed increased Foxp3⁺ T-cell frequencies, and a significant change in the gut microbiota, particularly an increase in the abundance of Bacteroidetes and a decrease in the Firmicute members. Oral administration of YBG, together with Raldh-substrate and β-cell antigen, resulted in better protection of NOD mice from T1D. These observations suggest that YBG not only has a prebiotic property, but also an oral tolerogenic-adjuvant-like effect, and these features could be exploited for modulating autoimmunity in T1D.     

IL-4, IL-10 and IL-13 down-regulate monocyte-chemoattracting protein-1 (MCP-1) production in activated intestinal epithelial cells

Several studies have demonstrated that intestinal epithelial cells play a major role in the initiation and perpetuation of intestinal inflammation by secreting proinflammatory cytokines and chemokines. MCP-1 is suggested to be a chemokine that plays a major part during intestinal inflammation in inflammatory bowel disease (IBD). Immunoregulatory cytokines such as IL-4, IL-10 and IL-13 have been described to exert anti-inflammatory properties on various cell types. The aim of our study was to determine the effect of Th2 cytokines on the production of MCP-1 by activated intestinal epithelial cells. We examined Caco-2 cells as well as intestinal epithelial cells which were isolated from surgical specimens. Production of the chemokine MCP-1 was determined under stimulated and non-stimulated conditions. IL-4, IL-10 and IL-13 were added to stimulated epithelial cells under various culture conditions. Supernatants were analysed for cytokine concentrations using ELISAs. Under stimulation with physiological agents like IL-1β or tumour necrosis factor-alpha (TNF-α), we observed markedly increased concentrations of MCP-1 in supernatants of Caco-2 cells and intestinal epithelial cells. IL-4, IL-10 and IL-13 all had the capacity to down-regulate the production of MCP-1 in Caco-2 cells as well as in freshly isolated epithelial cells. Caco-2 cells which were primed with Th2 cytokines 24 h before stimulation were subsequently decreased in their ability to be stimulated by IL-1β or TNF-α for MCP-1 production. As MCP-1 has been shown to play a major role during intestinal inflammation, the in vitro suppression of MCP-1 in enterocytes suggests the in vivo use of regulatory cytokines in patients with active IBD.     

Contributions of mucosal immune cells to methotrexate-induced mucositis

The use of high doses of the anti-cancer drug methotrexate (MTX) is associated with intestinal damage. As a result, mucosal immune cells become increasingly exposed to a vast amount of microbial stimuli. We aimed at determining whether these cells are still functional during MTX treatment. Furthermore, we assessed if activation of the mucosal immune system would play a role in the pathogenesis of mucositis. A contributive role to mucositis for the adaptive immune system was established by showing that mucosal lymphocytes from MTX-treated mice secreted enhanced amounts of cytokines upon ex vivo polyclonal stimulation. Next, in vitro experiments revealed that macrophages were not affected by MTX in the capacity to produce tumor necrosis factor-alpha (TNF-alpha) and IL-10 after LPS exposure. Moreover, peritoneal macrophages from MTX-treated mice produced more IL-10 and TNF-alpha upon LPS stimulation, compared with cells derived from control mice. These data indicate a persistence of both innate and adaptive immune responses in this model. The clinical relevance of these findings was further established by the fact that LPS exposure prior to MTX treatment aggravated the course of mucositis. Furthermore, LPS-responsive mice recovered more slowly compared with LPS-unresponsive mice from MTX treatment. Finally, we found an increase in weight loss and intestinal damage upon MTX treatment in IL-10-deficient mice in comparison to wild-type controls, suggesting a protective role for IL-10 in mucositis. We conclude that mucosal immune responses remain resilient during MTX-induced mucositis. Whereas TNF-alpha production may contribute to mucosal damage, IL-10 may regulate by restricting excessive mucositis.     

Small intestine mucosal immune system response to high-fat-high-cholesterol dietary supplementation in male rats

The immune effects of high-fat-high-cholesterol (HFHC) diet supplementation were investigated in Sprague–Dawley male rats. The rats were administered HFHC for 8 weeks via oral gavage. Two control groups received either a normal rat diet (NRD) or skim milk along with NRD. The levels of interleukin (IL)-1β, IL-10 and tumour necrosis factor (TNF)-α were assessed, using enzyme-linked immunosorbent assay, in the ileum, the mesenteric lymph node (MLN), and the splenic tissue homogenates, and in blood. Histopathological examination of the intestinal tissues was performed and showed no abnormalities among groups. An HFHC supplementation resulted in a significant increment in the levels of IL-1β and IL-10 in the intestinal tissues. TNF-α concentration was only changed in MLN tissue homogenates where it was downregulated after HFHC treatment. No other changes were reported in the spleen tissue homogenate and serum. The cytokine concentrations proposed using HFHC diet as a safe immune manipulator for gastrointestinal mucosal surfaces.     

An Extract of the Medicinal Mushroom Agaricus blazei Murill Differentially Stimulates Production of Pro-inflammatory Cytokines in Human Monocytes and Human Vein Endothelial Cells in vitro

An extract of the edible mushroom Agaricus blazei Murill (AbM) has known antitumor and anti-infection properties, probably mainly by stimulating mononuclear phagocytes of the native immune system. The aim of this work was to study the effect of AbM on the production by human monocytes and human umbilical vein endothelial cells (EC) of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, TNFα), the anti-inflammatory/T regulatory cytokine IL-10 and the pro-Th1 cytokine IL-12. AbM, in concentrations from 1–15%, induced a considerable and dose-dependent increase in production of IL-8, IL-6, TNFα and IL-1β in monocyte cultures. The biosynthesis reached a plateau at a concentration of 10% of AbM, and was most pronounced for the three former cytokines. AbM did also dose-dependently stimulate EC production of IL-8,IL-6 and TNFα, but at lower levels compared with the monocytes. AbM did neither induce synthesis of cytokines IL-10 nor IL-12 in monocytes or EC. Our results demonstrate the differential effect of AbM stimulation on the magnitude of pro-inflammatory cytokines produced by monocytes and EC.     

外科及移植和麻醉应激对机体细胞因子活性的影响

背景：外科患者的康复过程是否顺利与多种因素有关,其中免疫因素是重要因素之一,细胞因子是免疫功能的主要组成,也是近年来研究的热点,手术的精神刺激、麻醉刺激、手术实质刺激、术后麻醉手术反应刺激等都可导致患者体内细胞因子发生改变,从而影响患者的康复。 目的：综述外科及移植和麻醉应激对机体细胞因子活性的影响。 方法：由一作者应用计算机检索2005-01/2010-10万方、维普、龙源期刊网、中国知网相关文章,中文检索词为“手术,麻醉,细胞因子”,英文检索词为“surgery,anesthesia,cytokines”。共检索到文献72篇,最终纳入符合标准的文献26篇。 结果与结论：手术可导致机体细胞因子失衡,尤其是白细胞介素6、白细胞介素10、白细胞介素1、白细胞介素2、白细胞介素8、肿瘤坏死因子α变化(增高)明显;传统手术与腹腔镜手术相比,后者细胞因子变化不明显,说明细胞因子变化与机体损伤程度有关。全麻也可导致机体细胞因子失衡,而硬膜阻滞麻醉对细胞因子影响不明显。手术、创伤、全麻都可以导致体内细胞因子失衡,从而影响机体免疫系统、内分泌系统等,进而影响机体的康复;硬膜阻滞麻醉/硬膜阻滞麻醉辅助其他麻醉对机体细胞因子平衡影响较少。在外科临床工作中,进行外科手术时尽量选择创伤小的麻醉和手术方法。     

Short-Chain Fatty Acids Regulate Secretion of IL-8 from Human Intestinal Epithelial Cell Lines in vitro

Short-chain fatty acids (SCFAs) including acetate, propionate and butyrate play an important role in the physiological functions of epithelial cells and colonocytes, such as immune response regulation. Human intestinal epithelial cells (IECs) contribute in intestinal immune response via different ways, such as production of different immune factors including Interleukin (IL) IL-8, which act as chemoattractant for neutrophils, and subsequently enhance inflammation. Therefore, we aimed to evaluate the effects of SCFAs on IECs viability and production of IL-8 in vitro. SCFAs were co-cultured with either normal intestinal epithelial (T4056) or adenocarcinoma derived (HT-29) cell lines for 24–96?h in the presence of E.coli lipopolysaccharides (LPS). Cell viability, proliferation, production of IL-8 and expression of IL-8 mRNA were determined in the cell cultures. The result showed that 20?mM of SCFAs was non-cytotoxic to T4056 and enhanced their growth, whereas the growth of HT-29 was inhibited. The SCFAs down regulated LPS-stimulated IL-8 secretion with different response patterns, but no obvious effects on the release of IL-8 from non LPS- stimulated cells. In conclusion, SCFAs showed regulatory effect on release of LPS-stimulated IL-8 as well as the expression of mRNA of IL-8; these might explain the anti-inflammatory and anti-carcinogenic mechanism of SCFAs.     

Retinoic Acid Enhances the Production of IL-10 While Reducing the Synthesis of IL-12 and TNF-α from LPS-Stimulated Monocytes/Macrophages

Vitamin A and its metabolites, e.g., all trans-retinoic acid (atRA) and 9-cis-retinoic acid have attracted considerable attention as compounds that have a broad range of immune modulating effects on both humoral and cellular immune responses. The cellular and molecular mechanisms that underlie the effects of retinoids on the immune system remain to be more clearly defined. These immune modulating effects of atRA may be mediated by cytokines elaborated by monocytes and other cell types. To further understand the mechanism(s) by which retinoids affect the immune response, we examined the effects of atRA on several proinflammatory and immune modulating cytokines produced by monocytes. The effects of atRA on LPS-induced mRNA expression of IL-10, IL-12p40, TNF-α, IL-18, and TGF-β in the THP-1 monocyte/macrophage cell line and in cord blood mononuclear cells were measured by competitive RT-PCR. The ELISPOT was employed to evaluate IL-10 and TNF-α protein production enumerating the number of IL-10 and TNF-α producing cells. The addition of atRA to cell cultures potentiated the LPS-induced IL-10 mRNA expression and the number of IL-10 secreting cells from THP-1 cells and cord blood mononuclear cells. In contrast, the addition of atRA inhibited the LPS-induced TNF-α and IL-12p40 mRNA expression, and the number of ELISPOT positive cells for TNF-α. atRA did not change the LPS-induced mRNA expression of IL-18 and TGF-β. These results suggest that atRA may have multiple effects on LPS-induced monocyte/macrophage derived cytokines. While atRA downregulated the proinflammatory cytokines, e.g., IL-12 and TNF-α, the production of an immune modulating cytokine, IL-10 was enhanced by atRA. The effects of atRA on these cytokines may play an important role in the modulation of the immune and inflammatory responses.     

Lamina propria macrophages and dendritic cells differentially induce regulatory and interleukin 17-producing T cell responses

The intestinal immune system must elicit robust immunity against harmful pathogens but must also restrain immune responses directed against commensal microbes and dietary antigens. The mechanisms that maintain this dichotomy are poorly understood. Here we describe a population of CD11b+F4/80+CD11c- macrophages in the lamina propria that expressed several anti-inflammatory molecules, including interleukin 10 (IL-10), but little or no proinflammatory cytokines, even after stimulation with Toll-like receptor ligands. These macrophages induced, by a mechanism dependent on IL-10, retinoic acid and exogenous transforming growth factor-beta, the differentiation of Foxp3+ regulatory T cells. In contrast, lamina propria CD11b+ dendritic cells elicited IL-17 production. This IL-17 production was suppressed by lamina propria macrophages, indicating that a dynamic interaction between these subsets may influence the balance between immune activation and tolerance.     

Grape seed extract (GSE) modulates campylobacter pro-inflammatory response in human intestinal epithelial cell lines

The main aim of this study was to investigate the effect of Grape seed extract (GSE) on Campylobacter induced-cytokine production by human intestinal cell lines. With this purpose, Caco-2 and HT-29 cells were challenged with culture supernatants from several strains of C. jejuni and levels of secreted IL-6, IL-8, and MCP-1 were measured. Cytokine production was higher in HT-29 than in Caco-2 cells, showing different levels of secretion depending of the epithelial cells origin. Also, infective isolates coming from campylobacteriosis patients rendered higher levels of pro-inflammatory cytokines. Co-treatment and pre-treatment of HT-29 cells with GSE and C. jejuni significantly reduced cytokines production in a dose-dependent manner. These results make this natural product a putative nutritional tool for use in the treatment of campylobacteriosis, which could contribute to improve disease prevention or reduce disease severity.     

Vasoactive Intestinal Polypeptide Suppressed Experimental Autoimmune Encephalomyelitis by Inhibiting T Helper 1 Responses

Vasoactive intestinal peptide (VIP) has been found to act as a potent anti-inflammatory factor through regulating the production of both anti- and pro-inflammatory mediators and promoting Th2-type responses. In this study, we used myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (EAE) model in C57BL/6 mice to investigate the potential effects of VIP on multiple sclerosis. Our results showed that in vivo treatment of EAE-induced mice with VIP had great protective benefit at both clinical and histological levels. Disease suppression was associated with the inhibition of T cells proliferation, shifting of the immune response toward a Th2-type response and influencing the expression of pro-inflammatory cytokines including IFN-γ, IL-6 and IL-2 as well as chemotactic factors such as RANTES. In conclusion, the study provides evidence that VIP had great protective effect on EAE through its inhibition actions on pathogenic T cells and through a specific effect on the Th1 response.Haiyan Li and Yunhua Mei contributed equally to this work     

Serum levels of TGFβ, IL-10, IL-17, and IL-23 cytokines in β-thalassemia major patients: the impact of silymarin therapy

Several immunological abnormalities have been characterized in β-thalassemia, many of which are linked to or identified with cytokines. In this study, we investigated the serum levels of TGF-β, IL-10, IL-17 and IL-23 in β-thalassemia major patients in comparison with healthy controls. The immunomodulatory effect of silymarin (a flavonoid complex obtained from Silybum marinum) on the serum levels of cytokines was further evaluated in thalassemia patients receiving silymarin (420?mg/day) and compared with patients treated with placebo for 6-month. Serum cytokines levels were measured by enzyme linked immunosorbent assay (ELISA). The results showed a significant higher concentration of TGF-β and IL-23 in the patient group than control group. Among studied cytokines, a significant reduction in serum IL-10 levels was found in patients treated with silymarin when compared with IL-10 values at baseline. However, no significant difference was observed between baseline values of cytokine compared with end values in placebo group. Our data suggest the presence of imbalanced immune condition involving inflammation and immunosuppression in thalassemia patients, which could be modulated to a more effective immune response by silymarin.     

Immune complex-induced interleukin-6, interleukin-10 and prostaglandin secretion by human monocytes: a network of pro- and anti-inflammatory cytokines dependent on the antigen: antibody ratio

We have used two experimental models of immune complexes to study the secretion of interleukin (IL)-10, IL-6 and their connection with the immune complex-induced synthesis of prostaglandin (PG) E2 by human monocytes in vitro. Immune complexes formed of tetanus toxoid and polyclonal anti-tetanus toxoid antiserum as well as heat-aggregated human serum immunoglobulins induced the release of IL-6 and IL-10 in a dose- and antigen: antibody ratio-dependent manner. Antigen-antibody complexes formed near equivalence were most effective in induction of a cytokine response. PGE2 could augment the immune complex-induced IL-6 and IL-10 secretion, but alone, did not induce cytokine secretion. IL-10 was capable of down-regulating the release of IL-6 and PGE2. Additionally, we demonstrated that endogenously synthesized IL-10 limited the immune complex-induced secretion of proinflammatory cytokines tumor necrosis factor-α and IL-1β. All three regulatory factors examined here share anti-inflammatory properties and are closely associated with the T helper type 2 (Th2) immune response. We conclude that immune complexes, besides their well-known ability no cause acute and chronic inflammation, can mediate immunosuppressive effects and influence the balance of Th1/Th2 responses.     

Dietary intervention with narrow-leaved cattail rhizome flour (Typha angustifolia L.) prevents intestinal inflammation in the trinitrobenzenesulphonic acid model of rat colitis

ABSTRACT: BACKGROUND: Inflammatory bowel disease (IBD) is a chronic inflammation of the intestinal epithelium that is driven by the intestinal immune system, oxidative stress and the loss of tolerance to the luminal microbiota. The use of dietary products containing ingredients such as fibres and carbohydrates and/or antioxidant compounds have been used as a therapeutic strategy for intestinal diseases because these products are considered effective in the modulation of the immune system and colonic microbiota. We investigated the beneficial effects of cattail rhizome flour (Typha angustifolia L.) in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis. In addition, we investigated the effects of cattail rhizome flour on the intestinal anti-inflammatory activity of prednisolone, which is a reference drug that is used for treatment of human IBD. METHODS: The present study included the preparation of flour from rhizomes of cattail (Typha angustifolia L.); an evaluation of the qualitative phytochemical profile of cattail rhizomes; an evaluation of the efficacy of cattail rhizome flour in TNBS-induced rat colitis; an evaluation of the synergistic effects of cattail rhizome flour on the intestinal anti-inflammatory activity of prednisolone; and macroscopic, clinical, biochemical, histopathological and microbiological studies to assess the healing effects of cattail rhizome flour and its synergistic effects in TNBS-induced rat colitis. The data were analysed by ANOVA, Kruskal-Wallis and chi2 tests. RESULTS: We tested several concentrations of cattail rhizome flour and found that dietary supplementation with 10% cattail rhizome flour showed the best effects at reducing the extension of the lesion, the colon weight ratio, adherences to adjacent organs and diarrhoea. These effects were related to inhibition of myeloperoxidase (MPO) and alkaline phosphatase (AP) activities and an attenuation of glutathione (GSH) depletion. The 10% cattail rhizome flour was as effective as prednisolone, and no synergistic effects were observed. Saponins, flavonoids and coumarins were detected in the rhizome flour. No changes were observed in the total number of lactic bacteria after dietary supplementation with cattail rhizome flour. CONCLUSIONS: Dietary supplementation with 10% cattail rhizome flour and its combination with prednisolone prevent TNBS-induced colonic damage in rats, but no synergistic effects were observed. The prevention of TNBS-induced colon damage was associated with an improvement in intestinal oxidative stress, which likely resulted from the antioxidant properties of the active compounds detected in the cattail rhizome. This protective effect was not related to an improvement in lactic bacteria counts.     

IL-4 enhances IEC-6 intestinal epithelial cell proliferation yet has no effect on IL-6 secretion

Intestinal epithelial cells (IEC) form an important line of defence at the intestinal mucosa by providing a barrier to lumenal contents and also by their ability to secrete various inflammatory cytokines. Recently, several T cell-derived cytokines have been shown to regulate specific IEC functions. In this study, the effect of IL-4 on IEC proliferation and secretion of the inflammatory cytokine IL-6 was investigated using the non-transformed rat IEC-6 intestinal epithelial cell line. Recombinant rat (rr)IL-4 was found to enhance IEC-6 cell proliferation over 4 days of culture, and this enhancement was dose-dependent. Further studies using specific antibodies confirmed that IL-4 induced the effect and that the effect was not mediated by autocrine-produced transforming growth factor-alpha. However, IL-4 did not induce IL-6 secretion by the IEC-6 cells, nor did it alter IL-1β-induced IL-6 secretion. These results indicate that T cells may be capable of regulating IEC proliferation via the secretion of IL-4 without altering the capacity of the IEC to function in the inflammatory response by secreting IL-6.     

Curculigoside augments cell-mediated immune responses in metastatic tumor-bearing animals

A positive modulation of immune system is necessary for preparing the body to fight against malignant tumor cells. In the present study, the stimulatory effect of Curculigoside on cell-mediated immune response against the metastasis of B16F10 melanoma cells was analyzed in C57BL/6 mice. Curculigoside is a phenolic glucoside present in the plant Curculigo orchioides Gaertn. (Family – Amaryllidaceae). Administration of Curculigoside enhanced the natural killer (NK) cell activity, antibody-dependent cell-mediated cytotoxicity and complement-mediated cytotoxicity in metastatic tumor-bearing animals, when compared to the untreated control animals. The compound was also found to be effective in reducing the levels of proinflammatory cytokines such as TNF-α, IL-1β, IL-6 and GM-CSF during metastasis. Besides these, levels of TH1 cytokines, such as IL-2 and IFN-γ, were significantly enhanced (p?相似文献   

Expression of cytokine mRNAs in murine hearts with acute myocarditis caused by coxsackievirus B3

In murine acute viral myocarditis, natural killer (NK) cells infiltrate the heart first, followed by activated T-cells, which play an important role in the pathogenesis of the myocardial damage. Because of their multipotential effects, cytokines are thought to play a role in the induction and development of these immune processes. To clarify in more detail the precise mechanism of the cytokine networks involved, the expression of various cytokine mRNAs has been investigated in myocardial cells infected with Coxsackievirus B3 (CVB3) in vivo and in vitro by a semiquantitative polymerase chain reaction (PCR) method. Interleukin (IL)-1α, IL-1β, IL-6, tumour necrosis factor (TNF)-α, and TNF-β were expressed almost throughout the early phase of virus infection with some variations. IL-2, IL-3, IL-4, IL-10, interferon (IFN)-γ, granulocyte/macrophage colony stimulating factor (GM-CSF), and IL-2 receptor (IL-2R) were mainly expressed by the infiltrating cells. TNF-α, TNF-β, and IL-1β were also expressed partly by the infiltrating cells. T-helper (Th)1-related cytokines (IL-2, IFN-γ, and TNF-β) were more strongly expressed than Th2-related cytokines (IL-4 and IL-10) in vivo, indicating that the Th cells which infiltrated the heart and mediated the immune responses in the early phase of acute myocarditis were mainly of Th1-type. © 1997 by John Wiley & Sons, Ltd.     

Cytokines related to three major types of cell-mediated immunity in short- and long-term exposures to lead compounds

Many investigators have posited on the significant influence of lead on the immune system function. However, available data on this topic are not conclusive. Therefore, a study was undertaken to examine associations between lead exposure and levels of cytokines related to the T-helper (T_H)-1, T_H2, and T_H17 types of immune response in humans. For these analyses, three population groups were examined: the first consisted of male workers exposed to lead for a short period of time (36–44 days); the second included male workers chronically exposed to lead (13?±?10 years); and a control group that was composed of male administrative workers with blood lead levels (BLL)?H1 cells), IL-4, IL-5, IL-13 (related to T_H2 cells), and IL-17A (related to T_H17 cells) did not change after a short-term exposure to lead (compared to baseline). However, the levels of all of these cytokines were significantly higher in workers chronically exposed to lead than in the controls by 82%, 32%, 81%, 22%, 70%, 42%, and 17% (IFNγ, IL-2, IL-12, IL-4, IL-5, IL-13, IL-17A, respectively). From these studies, we conclude that in humans, a short-term exposure to lead does not affect levels of cytokines related to the T_H1-, T_H2-, and T_H17-mediated immune responses, while chronic exposure modifies their levels. Taken together, these modifications do not evidence an ability of lead to promote specifically one type of immune response in an exposed host.     

Effect of long-term continuous consumption of fermented milk containing probiotic bacteria on mucosal immunity and the activity of peritoneal macrophages

The effect of the long-term administration of commercial fermented milk containing probiotic bacteria in the mucosal immune response and peritoneal macrophages was analyzed. BALB/c mice were fed with fermented milk for 98 consecutive days. Small and large intestines were removed for histology; IgA, CD4, CD8 cells and cytokines-producing cells were counted. The influence on the immune cells associated with bronchus and mammary glands as well as on peritoneal macrophages was also analyzed. Continuous oral administration of fermented milk increased IgA+ cells in both parts of the intestine (small and large intestine). IL-10, a regulatory cytokine, increased in the intestinal cells in most samples. TNFalpha, IFNgamma and IL-2 producing cells were also enhanced. Values for CD4 and CD8(+) cell populations in lamina propria of the intestine were increased in relation to the control throughout the assay. No modifications in the histology of intestines were observed. Long-term consumption of fermented milk enhanced intestinal mucosa immunity, mediated by IgA+ cells and by cytokine production. This improvement of gut immunity was maintained and down-regulated by cytokines such as IL-10, preventing gut inflammatory immune response. The effect of this fermented milk on mucosal sites distant to the gut, such as bronchus and mammary glands, showed that in both tissues the increase in IgA+ cells was only observed at the beginning of the continuous consumption and no modifications in the number of cytokine positive cells were found. Similar observations were found when phagocytic activity of peritoneal macrophages was measured. It was demonstrated that the most evident effect of long-term consumption of fermented milk was observed in the intestine. Immunodulatory effects and the maintenance of intestinal homeostasis without secondary effects after long-term administration of fermented milk were also observed.