Immunological effects of yogurt addition to a re-nutrition diet in a malnutrition experimental model

The therapeutic and preventive effects of yogurt and lactic acid bacteria on diseases such as cancer, infection and gastrointestinal disorders are well ocumented. The aim of this research was to study the effects of different doses of yogurt addition after milk re-nutrition diet, on the recovery of the intestinal barrier and mucosal immune function. Experiments were performed on groups of mice, malnourished and re-nourished with milk during 7 d, and mice with diet supplemented with yogurt for 2, 5 and 7 consecutive d. Nutritional parameters such as weight gain, serum total protein, and the number of IgA, IgM and IgG B cells of the small intestine were determined. We also quantified intraepithelial leukocytes, mastocytes and goblet cells, and performed structural and ultrastructural studies on the small intestine. We observed that 5 d of yogurt feeding was the optimal dose for improving gut barrier function and mucosal immune system in a malnutrition model. This effect was not observed with milk re-nutrition. Although the results were better for 5 d of yogurt, addition for 7 d also showed beneficial effects. Yogurt feeding in our model did not impair any gut functions. These results suggest that yogurt addition after a re-nutrition diet gives better recovery of intestinal function than the re-nutrition diet usually recommended. Although these results were obtained in an animal model, they indicate that consumption of yogurt by malnourished children might accelerate the restoration of gut function.     

Effects of ingestion of yogurts containing Bifidobacterium and Lactobacillus acidophilus on spleen and Peyer's patch lymphocyte populations in the mouse

Certain probiotic lactic acid bacteria have been reported to improve immune system function. Here, the effects of ingesting yogurts on lymphocyte populations in the spleens and Peyer's patches were determined in mice. Three probiotic-supplemented yogurts containing Streptococcus thermophilus, Lactobacillus bulgaricus, Bifidobacterium, and Lactobacillus acidophilus and one conventional yogurt containing only S. thermophilus and L. bulgaricus were prepared from commercial starter cultures and used in the study. B6C3F1 female mice were fed the four different types of yogurts mixed with an AIN-93G diet in a 50:50 (wt/wt) ratio. Nonfat dry milk mixed at a 50:50 (wt/wt) ratio with AIN-93G diet was used as the control. After a 14-day feeding period, spleen and Peyer's patches were removed and lymphocytes subjected to phenotype analysis by flow cytometry. Ingestion of the four yogurts had no effect on percentages of CD8+ (cytotoxic T cells), B220+ (B cells), IgA+, or IgM+ cells in spleen or Peyer's patches. The percentage of CD4+ (T helper) cells was significantly increased in the spleens from one group of mice fed a yogurt containing Bifidobacterium and L. acidophilus, and a similar trend was found in the remaining two probiotic-supplemented yogurts. Effects on CD4+ populations were not observed in spleens of mice fed conventional yogurt or in the Peyer's patches of any of the four yogurt groups. In total, the results suggested that ingestion of conventional or probiotic-supplemented yogurts for 2 weeks had very little effect on lymphocyte distribution in the systemic or mucosal immune compartments.     

Immunoadjuvant activity of oral Lactobacillus casei: influence of dose on the secretory immune response and protective capacity in intestinal infections.

Lactobacilli, often used as effectors of host functions, could play an important role in maintaining human health by controlling other intestinal microorganisms capable of producing harmful effects. Using an experimental model, we studied the effect of different oral doses of Lactobacillus casei on the secretory IgA response and the protective capacity of the microorganism in preventing intestinal infections. The optimization of the protective dose of Lb. casei by previous feeding and the use of the lactobacillus as an immunological way to control enteric infections were investigated. We found that conventional mice were protected against infection with Salmonella typhimurium and Escherichia coli by previous feeding for 2 consecutive days with a daily Lb. casei dose of 1.2 x 10(9) cfu/mouse. Previous feeding for 7 d proved less effective, and feeding for 5 d afforded no protection at all. We were also able to demonstrate that the protective effect of Lb. casei against Sal. typhimurium and Esch. coli was connected mainly with the high level of IgA antipathogen antibodies present in intestinal secretions. beta-Glucuronidase (EC 3.2.1.31) and beta-galactosidase (EC 3.2.1.23) activities, measured both in the intestinal fluid and histological samples, showed a marked increase in intestinal inflammatory response on day 5 of feeding. These results show that Lb. casei plays an important role in the prevention of enteric infections, a low dose being enough for protection against intestinal infections by increasing IgA secretion into the intestinal lumen, thus providing adequate defences for the mucosal surface. A previously administered dose of this magnitude could therefore be used as an oral adjuvant in preventing enteric infections.     

Study of the possible mechanisms involved in the mucosal immune system activation by lactic acid bacteria.

The induction of a mucosal immune response is not easy due to the development of oral tolerance, but under some conditions, bacteria can activate this immune system. Antigens administered orally can interact with M cells of Peyer's patches or bind to the epithelial cells. We have demonstrated that certain lactic acid bacteria are able to induce specific secretory immunity, and others will enhance the gut inflammatory immune response. The aim of this work was to establish the reason for these different behaviors and to define possible mechanisms involved in the interaction of lactic acid bacteria at the intestinal level. We studied IgA+ and IgM+ B cells comparatively in bronchus and intestine and CD4+ T cells and IgA anti-lactic acid bacteria antibodies in the intestinal fluid, induced by oral administration of Lactobacillus casei, Lb. delbrueckii ssp. bulgaricus, Lb. acidophilus, Lb. plantarum, Lb. rhamnosus, Lactococcus lactis, and Streptococcus salivarius ssp. thermophilus. The increase in the IgA+ B cells in the bronchus means that these lactic acid bacteria were able to induce the IgA cycle by interaction with M cells from Peyer's patches or intestinal epithelial cells. The IgM+ cells increased when the stimulus did not induce the switch from IgM+ to IgA+. The increase in the CD4+ cells suggests interaction of Peyer's patches and enhancement of the B- and T-cell migration. The anti-lactic acid bacteria antibody is related to the processing and presentation of the microorganisms to the immune cells. We demonstrated that Lb. casei and Lb. plantarum were able to interact with Peyer's patch cells and showed an increase in IgA-, CD4+ cells, and antibodies specific for the stimulating strain. Lactobacillus acidophilus induced gut mucosal activation by interaction with the epithelial cells without increase in the immune cells associated with the bronchus. Although Lb. rhamnosus and Strep. salivarius ssp. thermophilus interact with epithelial cells, they also induced an immune response against their epitopes. Lactococcus lactis and Lb. delbrueckii ssp. bulgaricus induced an increase of IgA+ cells entering the IgA cycle but not CD4+ cells; thus, these bacteria would have been bound to epithelial cells that activated B lymphocytes without processing and presenting of their epitopes. We did not determine specific antibodies against Lc. lactis or Lb. bulgaricus.     

含酸奶饲料对衰老小鼠某些免疫功能指标的影响

用含Lactobacillus bulgaricus和Streptococcus Thermophilus活菌酸奶30％的饲料饲喂衰老小鼠3d，测定其胸腺重量、脾淋巴细胞增殖能力、IL-2（Interleukin，IL）产生量、脾T淋巴细胞中CD4^＋／CD8^＋细胞比例等指标，发现饲喂酸奶显著增加了胸腺重和IL-2的产生量,提高了脾T淋巴细胞的增殖能力，但未达到年轻小鼠的水平。此外还观察到酸奶处理提高了T淋巴细胞中CD4^＋／CD8^＋细胞的比例。这些结果表明，酸奶对于老年小鼠的免疫功能具有一定恢复作用。     

Prevention of gastrointestinal infection using immunobiological methods with milk fermented with Lactobacillus casei and Lactobacillus acidophilus

The protective effect of feeding milk fermented with a mixture of Lactobacillus casei sp. and Lb. acidophilus sp. against Salmonella typhimurium infection in mice was compared with that obtained feeding milks fermented with these microorganisms individually. The survival rate obtained after oral infection with Sal. typhimurium was 100% in mice pretreated by feeding during 8 d with the mixture of Lb. casei and Lb. acidophilus fermented milks. Similar treatments with the individual milks were ineffective. Moreover, mice became more susceptible to infection with Sal. typhimurium after such treatment. The colonization of liver and spleen with the pathogen was markedly inhibited by the pretreatment with the mixture of fermented milk, while such inhibition was not observed using the Lb. casei and Lb. acidophilus milks. The highest levels of anti-salmonellae antibodies in serum and in intestinal fluid were found in the group of mice fed with the mixture and with Lb. casei fermented milk respectively. However, this latter milk was not effective in protecting against Sal. typhimurium. When the mice were first infected with Sal. typhimurium and then fed with the mixture of fermented milks, pathogen colonization was not prevented. The results suggest that the augmentation of resistance to salmonellae caused by the treatment with Lb. casei- + Lb. acidophilus-fermented milk was due to the anti-salmonellae protective immunity mainly mediated by the mucosal tissue. Milk fermented with this mixture could be used as an immunobiological method to prevent gastrointestinal infection.     

Effect of fermented milk containing probiotic bacteria in the prevention of an enteroinvasive Escherichia coli infection in mice

This study investigated the protective capacity of the oral administration of fermented milk containing the probiotic strains; Lactobacillus casei, Lb. delbrueckii subsp. bulgaricus and Streptococcus thermophilus, against enteroinvasive Escherichia coli infection in a murine (BALB/ c mice) model. Mice were fed for 2, 5 or 7 consecutive days with fermented milk diluted to a concentration of viable Lb. casei, Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus of 10(7) cfu/ml. Phagocytic activity of peritoneal macrophages and the number of IgA+ cells in small and large intestine were determined at the end of the feeding periods. For the preventive effect against Esch. coli, animals were fed for 5 days (selected dose). Mice were challenged with an infective dose of enteroinvasive Esch. coli of 10(8) cfu/mouse. The colonization of liver and spleen and the secretory IgA specific for the pathogen in the intestinal fluid were determined (ELISA test). Results showed that the unspecific immune response enhanced itself after 5 consecutive days of the administration of this fermented milk (increase in the percentage of phagocytosis and number of IgA+ cells in the small intestine). Treated animals showed less Esch. coli colonization of liver than control mice and a higher secretory anti-Esch. coli IgA in the intestinal fluids. These results suggest that the protection against enteroinvasive Esch. coli infection observed for the fermented milk containing probiotic bacteria may be associated with an enhance of the intestinal mucosa immunity.     

Comparative evaluation of yogurt and low-fat cheddar cheese as delivery media for probiotic Lactobacillus casei

This study used Lactobacillus casei 334e, an erythromycin-resistant derivative of ATCC 334, as a model to evaluate viability and acid resistance of probiotic L. casei in low-fat Cheddar cheese and yogurt. Cheese and yogurt were made by standard methods and the probiotic L. casei adjunct was added at approximately 10(7) CFU/g with the starter cultures. Low-fat cheese and yogurt samples were stored at 8 and 2 degrees C, respectively, and numbers of the L. casei adjunct were periodically determined by plating on MRS agar that contained 5 microg/mL of erythromycin. L. casei 334e counts in cheese and yogurt remained at 10(7) CFU/g over 3 mo and 3 wk, respectively, indicating good survival in both products. Acid challenge studies in 8.7 mM phosphoric acid (pH 2) at 37 degrees C showed numbers of L. casei 334e in yogurt dropped from 10(7) CFU/g to less than 10(1) CFU/g after 30 min, while counts in cheese samples dropped from 10(7) CFU/g to about 10(5) after 30 min, and remained near 10(4) CFU/g after 120 min. As a whole, these data showed that low-fat Cheddar cheese is a viable delivery food for probiotic L. casei because it allowed for good survival during storage and helped protect cells against the very low pH that will be encountered during stomach transit.     

Immune System Stimulation by Probiotic Microorganisms

Probiotic organisms are claimed to offer several functional properties including stimulation of immune system. This review is presented to provide detailed informations about how probiotics stimulate our immune system. Lactobacillus rhamnosus GG, Lactobacillus casei Shirota, Bifidobacterium animalis Bb-12, Lactobacillus johnsonii La1, Bifidobacterium lactis DR10, and Saccharomyces cerevisiae boulardii are the most investigated probiotic cultures for their immunomodulation properties. Probiotics can enhance nonspecific cellular immune response characterized by activation of macrophages, natural killer (NK) cells, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in strain-specific and dose-dependent manner. Mixture and type (gram-positive and gram-negative) of probiotic organisms may induce different cytokine responses. Supplementation of probiotic organisms in infancy could help prevent immune-mediated diseases in childhood, whereas their intervention in pregnancy could affect fetal immune parameters, such as cord blood interferon (IFN)-γ levels, transforming growth factor (TGF)-β1 levels, and breast milk immunoglobulin (Ig)A. Probiotics that can be delivered via fermented milk or yogurt could improve the gut mucosal immune system by increasing the number of IgA⁺ cells and cytokine-producing cells in the effector site of the intestine.     

Elucidation of the inhibitory factors of yogurt against Salmonella typhimurium.

The inhibitory nature of yogurt against contaminating microorganisms has been studied extensively. Nevertheless, the factors responsible for the death of Salmonella typhimurium in yogurt have not been elucidated. An understanding of these factors is important for the determination of yogurt's safety to consumer health. Yogurt fermented for 18 h at 42 C had a stable environment with the following conditions: pH 3.85, oxidation-reduction potential -80 mV, lactic acid concentration 158 mM, and acetic acid concentration 3.7 mM. Under these conditions, lactic acid was responsible for virtually all of yogurt's bactericidal activity against S. typhimurium at 37 C. Die-off rates were observed when these conditions were reproduced artificially in milk (artificial milk yogurt) and when lactic acid was added back to 18-h yogurt from which acids were removed by passage of the whey through a Dowex 1 (Cl-) anion exchange column (cationic yogurt). Factors that augmented lactic acid inhibition of S. typhimurium were low pH and low oxidation-reduction potential. The die-off rate of S. typhimurium was more rapid in yogurt whey (yogurt minus the casein fraction) than in whole yogurt, indicating that the casein fraction was partially able to protect Salmonella.     

富硒酸奶发酵剂的制备及其发酵性能研究

以青春双歧杆菌ys01和干酪乳杆菌ys05为原料制备富硒酸奶发酵剂。在单因素试验基础上,采用Box-Behnken试验设计对青春双歧杆菌ys01和干酪乳杆菌ys05混合富硒条件进行优化,得到最佳富硒条件为低聚果糖1%、Se4+质量浓度6.83μg/mL、初始pH6.0、青春双歧杆菌ys01和干酪乳杆菌ys05接种比例2:1、接种量3.8%、培养温度42℃、培养24h加硒、培养时间60h。在上述条件下,青春双歧杆菌ys01和干酪乳杆菌ys05混合菌体含硒量为(551±4.6)μg/g,硒转化率为(42.2±3.6)%。利用青春双歧杆菌ys01和干酪乳杆菌ys05制备的富硒酸奶发酵剂具有良好的发酵性能,用其发酵制备富硒酸奶,其有机硒含量为(17±4.5)μg/kg。     

Application of S. faecalis and E. coli oral vaccines in humans and animals

Vaccines of non-pathogenic intestinal bacteria for oral administration have been used in the therapy of chronic and recurrent infections by the German Medical Association for Microbiological Therapy for over three decades. Three different oral bacterial vaccines were used in particular: 1. A sterile autolysate of non-pathogenic S. faecalis and E. coli; 2. a viable non-pathogenic S. faecalis vaccine, and; 3. a viable non-pathogenic E. coli vaccine. Clinical studies indicate the safety and efficacy of these bacterial products, and suggest the stimulation of immune activities and competitive capacities of S. faecalis and E. coli as mode of action. In animal experiments, orally administered intestinal bacterial vaccines enhance the resistance of mice against subsequent challenge with lethal doses of Salmonella typhimurium and Haemophilus influenzae. Mice were allowed access to a viable suspension of either S. faecalis or E. coli for at least 3 weeks. They were then challenged with either of the two unrelated pathogens. Both pre-treatment procedures conferred significant protection of the animals. The mechanism of this protective action appears to involve modification of white blood cell kinetics in the mice. The peritoneal resident cell population in mice is significantly increased by S. faecalis treatment.     

铁皮石斛提取物对小鼠慢性束缚结合睡眠剥夺模型免疫功能的影响

目的 通过网络药理学和动物实验探讨铁皮石斛的茎与花部位提取物对慢性束缚结合睡眠剥夺小鼠模型免疫功能的影响。方法 首先通过网络药理学预测石斛激活免疫细胞的靶点及通路;然后建立慢性束缚结合睡眠剥夺动物模型;采用石斛茎、花提取物(0.5 g/kg)对小鼠进行灌胃给药。31 d造模给药后,检测小鼠体能状态、小鼠自然杀伤(natural killer,NK)细胞、巨噬细胞活性、小鼠外周血中免疫细胞亚群(CD19+CD3e- B细胞、CD19-CD3e+ T细胞、CD4+CD3e+ Th细胞、CD4+CD3e- NK细胞)比例以及小鼠血清中细胞因子(白细胞介素4(interleukin-4,IL-4)、白细胞介素6(interleukin-6,IL-6)和免疫球蛋白G(immunoglobulin G,IgG)水平。结果 筛选出铁皮石斛14个潜在活性成分及 429个作用靶点, 与 884个作用于免疫细胞的靶点取交集得到 125个靶点,通过基因本体(gene ontology, GO) 功能富集分析得到直接参与免疫细胞调控的相关条目 25个,铁皮石斛可能通过促进B细胞、T细胞增殖分化,IL-6受体结合来激活免疫细胞,京都基因与基因组百科全书(kyoto encyclopedia of genes and genomes, KEGG)通路富集析12条,铁皮石斛激活免疫细胞与T细胞受体信号通路、B细胞受体信号通路、细胞周期信号通路等有关。铁皮石斛茎(Dendrobium officinale stem, SDO)、花(Dendrobium officinale flower, FD)组小鼠与模型(Model, MOD)组小鼠比较,跑台力竭时间、脾脏指数、胸腺指数显著提高(P < 0.05或P < 0.01),血液中NK细胞活性、巨噬细胞活性、CD19+CD3e- B细胞、CD19-CD3e+ T细胞、CD4+CD3e+ Th细胞、CD4+CD3e- NK细胞比例显著上升(P < 0.05或P < 0.01),血清中IL-4、IL-6、IgG的含量显著上升(P < 0.05或P < 0.01)。结论 铁皮石斛激活免疫细胞具有多成分、多靶点、多通路的特点。铁皮石斛花、茎提取物在慢性束缚结合睡眠剥夺模型中都具有提高小鼠免疫功能的作用。     

Immunostimulation in an animal model using intestinal bacteria preparations

The treatment of mice with an injection preparation consisting of killed R-tribes of non-pathogenous E. coli caused an increase in microbicidic activities in the animal's blood and effects a significant protection against consecutive infections with Salmonella typhimurium. The enhancement of the animal' resistance capacity appears to be non-specific, and connected with the activity of leucocytes. Oral application of preparations of intestinal bacteria led to increased resistance against consecutive infections with Salmonella typhimurium and Haemophilus influenzae. Three different oral vaccines have been used: Streptococcus faecalis and E. coli, a viable vaccine of non-pathogenous Streptococcus faecalis and a viable vaccine of E. coli. The enhancement of the resistance can be attributed to an induction of the chemotactic efficiency of the animal neutrophilic cells. The chemotactic response of these cells seems to be enhanced. The mode of action of both the other oral vaccines remains obscure.     

Dietary deprivation of fermented foods causes a fall in innate immune response. Lactic acid bacteria can counteract the immunological effect of this deprivation

Extrinsic factors such as maternal microbiota, bacterial load of the environment, diet and medication modulate the intestinal microbiota. Maturation and function of the immune system is influenced by established gut microbiota. In this work we describe the immunological effects of the dietary deprivation of fermented foods of healthy volunteers. Significant decreases in faecal lactobacillus and total aerobes counts and concentration of short chain fatty acids were observed following deprivation of fermented food of the normal diet. Moreover, a decrease in phagocytic activity in leukocytes was observed after two weeks of restricted diet. Therefore, the dietary deprivation of fermented foods could induce a decrease in innate immune response that might affect the capacity to respond against infections. The ingestion of a probiotic product containing the strains Lactobacillus gasseri CECT5714 and Lactobacillus coryniformis CECT5711 or a standard yogurt containing a conventional starter Lactobacillus delbrueckii sp. bulgaricus counteracted the fall in the immune response, although the probiotic product was more effective than the standard yogurt.     

嗜酸乳酸杆菌对自主活动受限型应激小鼠肠道黏膜免疫状态的影响

目的：探讨嗜酸乳酸杆菌（Lactobacillus acidophilus,LA）对自主活动受限型应激小鼠肠道黏膜免疫状态的影响。方法：以健康雌性BALB/c小鼠为受试动物,分为常规饲养组（NC组）、常规饲养条件灌胃LA组（NC＋LA组）、应激组（S组）、应激条件灌胃LA组（S＋LA组）,小鼠的LA灌胃剂量为108 CFU/d;应激组小鼠每天被限制自主活动3 h;15 d后取材,采用流式细胞术、酶联免疫吸附（enzyme-linked immunosorbent assay,ELISA）等方法,对肠系膜淋巴结（mesenteric lymph nodes,MLN）中CD4＋T细胞、CD8＋T细胞和CD11c＋树突细胞（CD11c＋ dendritic cell,CD11c＋ DC）比例,结肠组织白细胞介素-10（interleukin-10,IL-10）和白细胞介素-17（interleukin-17,IL-17）水平,以及小肠总分泌型免疫球蛋白A（secreted immunoglobulin A,sIgA）水平进行检测。结果：常规饲养条件下,LA能极显著提高小鼠MLN中CD4＋T细胞比例（P＜0.01）,显著提高MLN中CD11c＋ DC比例、小肠总sIgA水平和结肠组织IL-10水平（P＜0.05）,显著降低结肠组织IL-17水平（P＜0.05）,而对MLN中CD8＋T细胞比例无显著影响（P＞0.05）;应激条件能极显著降低小鼠MLN中CD4＋T细胞比例和CD11c＋ DC比例（P＜0.01）,显著降低CD8＋T细胞比例（P＜0.05）,极显著降低小鼠结肠组织IL-10水平和小肠总sIgA水平（P＜0.01）,极显著提高结肠组织IL-17水平（P＜0.01）;应激条件下,LA能显著提高小鼠MLN中CD4＋T细胞比例和CD11c＋ DC比例（P＜0.05）,显著提高小鼠结肠组织IL-10水平和小肠总sIgA水平（P＜0.05）,并显著降低结肠组织IL-17水平（P＜0.05）,而对小鼠MLN中CD8＋T细胞比例无显著影响（P＞0.05）。结论：给予自主活动受限型应激小鼠LA干预,可提高小鼠MLN中CD4＋T细胞和CD11c＋ DC比例,上调结肠IL-10和小肠总sIgA分泌水平,下调结肠IL-17分泌水平,调节应激小鼠的肠道黏膜免疫状态。     

单一干酪乳杆菌KL1发酵益生菌酸奶工艺条件的研究

应用单因素实验及正交实验,确定单一干酪乳杆菌KL1发酵酸奶的最佳原料乳,并对其益生菌酸奶发酵工艺条件进行优化。筛选得到的最佳原料乳为M₂,同时通过添加M₆改善酸奶的色泽与组织状态;采用三因素三水平L₉（3⁴）正交实验优化酸奶的发酵工艺条件,接种量是影响KL1发酵酸奶品质的最主要因素,确定干酪乳杆菌KL1发酵酸奶的优化条件如下:接种量为6.0%,M₆添加量1.0%,葡萄糖添加量1.5%,37℃下发酵酸奶22 h,优化后的益生菌酸奶的活菌数量较对照组高10倍。      

A cheese-containing diet modulates immune responses and alleviates dextran sodium sulfate-induced colitis in mice

Diet has a significant effect on immune and inflammatory responses. To date, no studies have described how consumption of a diet containing a relatively high amount of cheese affects immune responses and the inflammatory status of the body. We examined these responses in normal mice and mice with dextran sodium sulfate (DSS)-induced colitis associated with increased inflammatory responses, using a diet containing approximately 44% of a whole cheese powder and a diet containing casein, lard, and corn oil as the control. In normal mice, consumption of the cheese-containing diet induced regulatory T cells (T(reg)), which regulate immune and inflammatory responses, and suppressed the production of IL-17, IL-4, and IL-10 in Peyer's patch cells from the intestine. The T(reg) population and cytokine production were not altered in spleen cells. In mice with DSS-induced colitis, consumption of the cheese-containing diet alleviated the symptoms of colitis, as evidenced by prevention of body weight loss and colon length shortening, and inhibition of an increase in the disease activity index, which includes diarrhea and fecal bleeding. This relief of clinical symptoms was also associated with decreased production of proinflammatory cytokines (IL-17 and IL-6) and increased production of the antiinflammatory cytokine transforming growth factor-β1 in Peyer's patch cells. The T(reg) population was reduced by consumption of the cheese-containing diet in Peyer's patch cells and spleen cells, which might reflect the alleviated symptoms of colitis. Consumption of the cheese-containing diet compared with the control diet enhanced antiinflammatory and immune regulatory responses in normal mice and in a DSS-colitis mouse model.     

免疫调节性袋泡茶配方优化及功能性评价

目的：以绿茶、黄芪、党参、枸杞子、大枣为原料研制一款具有增强免疫力的功能性袋泡茶。方法：以感官评价为指标,应用正交试验结合模糊数学综合评定法优化袋泡茶配方,采用苯酚-硫酸法检测样品中总多糖含量。将SPF级昆明小鼠随机分为空白对照组、模型对照组、阳性对照组(1.40 mg/kg BW的蛋白粉)和袋泡茶低(0.52 g/kg BW)、中(1.04 g/kg BW)、高剂量组(1.56 g/kg BW),除空白对照组外,其余各组小鼠腹腔注射环磷酰胺制备免疫低下模型,连续给药21 d后测定小鼠体重和脏器指数;流式细胞术检测小鼠脾脏淋巴细胞CD3⁺细胞、CD4⁺细胞、CD8⁺细胞及CD4⁺CD8⁺细胞比例值;ELISA法测定小鼠血清中干扰素γ(interferon-γ,IFN-γ)含量。结果：袋泡茶的最佳配方为黄芪、党参、枸杞子、大枣、绿茶量分别为茶袋内容物总质量的13.00%、26.30%、20.50%、20.50%、19.70%,多糖含量为33.84±0.52 mg/g。药效实验结果...     

Effects of yogurt containing probiotics on respiratory virus infections: Influenza H1N1 and SARS-CoV-2

Respiratory virus infections are an escalating issue and have become common worldwide. Influenza and COVID-19 are typical infectious respiratory diseases, and they sometimes lead to various complications. In a situation in which no established drug or treatment exists, consumption of proper food might be beneficial in maintaining health against external infections. We studied the potential effects of mixtures of probiotic strains on various viral infections. The purpose of this study was to assess the ability of yogurt containing probiotics to reduce the risk of respiratory viruses such as influenza H1N1 and SARS-CoV-2 infection. First, we performed in vitro tests using infected Madin-Darby canine kidney (MDCK) and Vero E6 cells, to evaluate the potential effects of yogurt containing high-dose probiotics against influenza H1N1 and SARS-CoV-2 infection. The yogurt significantly reduced plaque formation in the virus-infected cells. We also performed in vivo tests using influenza H1N1-infected C57BL/6 mice and SARS-CoV-2-infected Syrian golden hamsters, to evaluate the potential effects of yogurt. Yogurt was administered orally once daily during the experimental period. Yogurt was also administered orally as pretreatment once daily for 3 wk before viral infection. Regarding influenza H1N1, it was found that yogurt caused an increase in the survival rate, body weight, and IFN-γ, IgG1, and IL-10 levels against viral infection and a decrease in the inflammatory cytokines TNF-α and IL-6. Although the SARS-CoV-2 copy number was not significantly reduced in the lungs of yogurt-treated SARS-CoV-2-infected hamsters, the body weights and histopathological findings of the lungs were improved in the yogurt-treated group. In conclusion, we suggest that consumption of yogurt containing probiotics can lead to beneficial effects to prevent respiratory viral infections.