Stimulated Lymphocyte Proliferation Research Articles

Effects of Mancozeb and Metribuzin on in vitro proliferative responses and oxidative stress of human and rat spleen lymphocytes stimulated by mitogens

Pesticides have been shown to possess marked immunotropic activity. The aim of this work was to study the in vitro effects of different concentrations (1–100 μM) of Mancozeb (fungicide) and Metribuzin (herbicide), on the proliferative responses of human and rat spleen lymphocytes stimulated by concanavalin A (ConA, mitogen), the Th1- (IL-2, INFγ) and Th2- (IL-4) cytokine secretion and on the intracellular oxidative status. The results showed that Mancozeb significantly reduced ConA lymphocyte proliferation in a dose-dependent manner in both humans and rats. It also decreased IL-2, INFγ and IL-4 secretion with a a shift away to Th1 phenotype. Metribuzin at low concentrations (1–10 μM) resulted in activation of ConA stimulated lymphocyte proliferation and cytokine production in both human and rat spleen cells. However, at high concentrations (25–100 μM), Metribuzin induced a dose-dependent inhibition of lymphocyte proliferation and cytokines. Changes in intracellular levels of reduced Glutathione, hydroperoxides and carbonyl proteins and in the activities of catalase and SOD were observed after Mancozeb and Metribuzin exposure reflecting oxidative stress and DNA damage specially at high concentrations. In conclusion, Mancozeb and Metribuzin had significant immunomodulatory properties with oxidative stress induction at high concentrations.

Protective effect of DNA vaccine with the gene encoding 55kDa antigen fragment against Pneumocystis carinii in mice

Objective To evaluate the protective effect of DNA vaccine with the gene encoding 55kDa antigen fragment of Pneumocystis carinii ( P. carinii) against P. carinii in mice. Methods The fragment of the antigen within p55(p55-582) was cloned. Then recombinant plasmid was constructed based on the eukaryotic expression vector pcDNA3.1(+). BALB/c mice were used as experimental models to examine the immunogenicity of pcDNA3.1(+)−p55-582. ELISA and RT-PCR were used to evaluate the role of this kind of DNA vaccine. Results The results of western blot indicated that the recombinant DNA[pcDNA3.1(+)−p55-582] could be expressed correctly and had antigenicity in transfected COS-7 cells. ELISA and RT-PCR showed that pcDNA3.1(+)−p55-582 elicited antibody production, stimulated lymphocyte proliferation and provided partial protection by reducing the P. carinii burden. Conclusions The data demonstrate that pcDNA3.1(+)−p55-582 might be potent vaccination that can afford the partial protection for the immunized animals.

Antagonistic and Agonistic Anti-canine CD28 Monoclonal Antibodies: Tools for Allogeneic Transplantation

It has been presumed that antibody-mediated selective costimulatory molecule blockade of CD28 is superior to cytotoxic T lymphocyte antigen 4 (CTLA4)-Ig. This is based on the premise that specifically blocking CD28 allows inhibitory signals through CTLA-4 to proceed, which furthermore suppresses T-cell function. The extracelluar domain of canine (ca)CD28 was cloned from dog peripheral blood mononuclear cells. Mice were immunized with a caCD28/murine IgG2a fusion protein. Hybridomas were produced by fusing splenocytes with mouse NSO cells and screened for caCD28 binding by ELISA. Agonistic and antagonistic activities of the monoclonal antibodies (mAb) were tested in mixed leukocyte reactions. Canine regulatory T cells were expanded using plate-bound anti-CD3 and an anti-CD28 agonist mAb. One agonistic and seven antagonistic mAbs to canine (ca)CD28 were cloned. Binding studies indicated that an agonistic (5B8) and an antagonistic (1C6) mAb bound equally well to a caCD28/caIgG1 fusion protein and to CD28 expressed on CD4+ and CD8+ peripheral blood T cells. Antagonistic antibody blocked mixed lymphocyte reactions (MLR) in a dose-dependent manner similar to CTLA4-Ig, whereas the agonistic antibody to caCD28 enhanced MLR. The 5B8 was superior to 1C6 when either was combined with anti-caCD3 to stimulate lymphocyte proliferation. Furthermore, the agonistic mAb, 5B8, together with anti-CD3 mAb induced 100-fold proliferation of canine regulatory T cells. Relative to untreated control cells, anti-caCD28 (1C6) and CTLA4-Ig equivalently inhibited cytotoxic T lymphocyte-mediated killing of alloreactive target cells. These studies demonstrated that mouse anti-caCD28 mAbs can be generated with agonistic or antagonistic function.

A Novel Tumor-Associated Pancreatic Glycoprotein Is Internalized by Human Dendritic Cells and Induces Their Maturation

Aberrant glycosylation or overexpression of cell-surface glycosylated tumor-associated Ags (TAA) distinguish neoplastic from normal cells. Interactions of TAA MUC1 and HER2/neu with dendritic cells (DC) preclude efficient processing, which impairs immune responses. It is thus important to define the mechanisms of interactions between DC and glycosylated TAA and their trafficking and processing for further T cell activation. In this work, we study interactions between DC and the oncofetal fucose-rich glycovariants of bile salt-dependent lipase (BSDL), expressed in pancreatic cancer tissues and referred to as pathological BSDL carrying the fucosylated J28 glycotope (pBSDL-J28) because it is characterized by the mAb J28. The expression of pBSDL-J28 was assessed by immunohistochemistry and quantified by confocal microscopy. Nontumoral pancreatic tissues and cells do not express pBSDL-J28. Using multidisciplinary approaches and functional studies, we provide the first evidence, to our knowledge, that this tumoral glycoprotein is rapidly internalized by human DC through macropinocytosis and endocytosis via mannose receptors and then transported to late endosomes for processing. Interestingly, pBSDL-J28 per se induced DC maturation with increased expression of costimulatory and CD83 molecules associated with cytokine secretion (IL-8 and IL-6). Surprisingly, DC retained their full ability to internalize Ags, making this maturation atypical. Finally, the allogeneic pBSDL-J28-treated DC stimulated lymphocyte proliferation. Besides, pulsing DC with pBSDL-J28 C-terminal glycopolypeptide and maturation with CD40L triggered CD4(+) and CD8(+) T cell proliferation. Therefore, interactions of pBSDL-J28, expressed on tumoral pancreatic tissue, with DC may lead to adequate Ag trafficking and processing and result in T cell activation.

The affect of chronic hepatitis C infection on dendritic cell function: a summary of the experimental evidence

Chronic hepatitis C virus (HCV) infection occurs in patients who fail to mount an effective T-cell response against the virus. One hypothesis for poor anti-viral immunity in these patients is that the virus impedes the immune response by disabling dendritic cells (DCs), cells that play a key role in pathogen recognition and initiation of adaptive immunity. Initial studies in the 1990s supported this hypothesis, as they clearly demonstrated that monocyte-derived DCs obtained from patients with chronic HCV infection displayed a reduced ability to stimulate lymphocyte proliferation. However, over the last 20 years, the situation has become more ambiguous. Many studies support the initial observation of a DC defect, while others using different patient cohorts or technologies have clearly demonstrated intact DC function in patients with chronic HCV. It is likely that the true situation lies somewhere in between. Just as there is a spectrum of disease in patients with chronic HCV, DCs obtained from different patients may display different properties. It is important to reconcile these divergent findings, as a clearer understanding of how the virus affects DC function will facilitate the development of immunotherapy and therapeutic vaccination strategies for patients with chronic HCV infection.

Evaluation of Serum Zinc Level Under Malignant Condition and its Possible Implication on Improving Cell-Mediated Immunity During Cancer Progression.

BackgroundZinc is an essential trace element required for different biological functions in a living body. Evaluating its concentration and effect during malignancy is important not only to assess the disease activity but also to evaluate its role in some important biological activities like immunity.MethodsThe experiments were carried out in transplanted, chemically induced and spontaneous tumors in mice. The serum zinc concentration (SZC) was determined under malignant condition and following treatment of solid tumor with anti-cancer agents. The importance of evaluating Cu/Zn ratio (CZR) was also determined. To evaluate its role in immune response during malignancy, studies were carried out on induced tumor bearing animals.ResultsThe results showed that SZC had an inverse correlation with the progression of the disease. It was significantly reduced in all forms of malignancy, more so in spontaneous and induced forms of the disease. Extensive studies done with the solid form of induced tumor, established the importance of estimating the concentration of Zn, in addition to that of copper, in assessing the disease activity following treatment with anti-cancer agents. With regression of the tumor mass, there was a significant elevation in the SZC and depression in the serum copper concentration (SCC) compared to their levels prior to treatment. This was also reflected on the value of copper zinc ratio (CZR); with the onset of tumor regression, a significant reduction in CZR was noted in the tumor bearing animals compared to their untreated levels. As the state of ‘regression’ in the tumor mass was maintained for a considerable period of time following treatment with anti-cancer agents along with elevated zinc levels, we considered the role of zinc in controlling the tumor growth, indirectly. We observed that zinc is able to stimulate lymphocyte proliferation that may directly impact on the immune response of tumor bearing host.ConclusionsZinc appears to play a role in tumor progression and regression and in stimulating lymphocyte proliferation. It is hypothesized that supplementing zinc to malignant subjects prior to and following therapeutic intervention with anti-cancer agents could help improve immune response of the host against existing tumor.

Acupuncture is effective to attenuate stress and stimulate lymphocyte proliferation in the elderly

Acupuncture has increasingly been used to treat many conditions, including psychiatric disorders and immunological-related disorders. However, the effects of acupuncture as stress management and immune functions in the elderly are largely unclear. Here we investigated the effects of acupuncture on stress-related psychological symptoms and cellular immunity in young adults and elderly subjects. The acupuncture treatment consisted of six sessions and the procedures included the insertion of needles at bilateral acupoints LI4, SP6 and ST36. Psychological variables (depression, anxiety and stress) were investigated by means of self-assessment inventories. Peripheral blood mononuclear cells were isolated and cultured in vitro to measure mitogen-induced T-cell proliferation as well as cellular sensitivity to dexamethasone. All data were assessed before and after the intervention. Acupuncture was able to significantly reduce depression ( p < 0.001), anxiety ( p < 0.001) and stress ( p < 0.001) scores. The intervention also increased T-cell proliferation, with greater intensity in the elderly group ( p = 0.004). No changes in cellular sensitivity to dexamethasone were observed following acupuncture. We conclude that acupuncture was efficient to attenuate the psychological distress as well as to increase an important feature of cellular immunosenescence.

Enhancement of immune responses to infectious bursal disease vaccine by supplement of an extract made from Momordica cochinchinensis (Lour.) Spreng. seeds

The immunological effect of an extract from Momordica cochinchinensis seed (ECMS) on immune responses against infectious bursal disease (IBD) in chickens was evaluated. Fifty-two birds were equally divided into 4 groups and immunized with inactivated IBD vaccine alone (controls) or IBD vaccine emulsified with ECMS (20, 40, and 80 microg). Serum IgG antibody levels against IBD and BW were measured on 0, 7, 14, 21, 28, and 35 d after immunization. The ELISA results revealed that the chickens that received 20 microg of ECMS had significantly enhanced antibody levels on 14, 21, 28, and 35 d when compared with controls (P<0.05). A significant increase in mitogenic stimulated lymphocyte proliferation was also recorded in all ECMS groups as compared with controls (P<0.05; P<0.01). No adverse effect of ECMS was noted on growth performance, although average weight gain was significantly higher in 20 microg (7, 14, 21, 28, and 35 d) and 40 or 80 microg (14 d) of ECMS groups as compared with controls (P<0.05; P<0.01). Further studies are suggested for the investigation of immunological effects of ECMS.

Epimedium polysaccharide and propolis flavone can synergistically stimulate lymphocyte proliferation in vitro and enhance the immune responses to ND vaccine in chickens

Four prescriptions, epimedium flavone plus propolis flavone (EF–PF), epimedium flavone plus propolis extracts (EF–PE), epimedium polysaccharide plus propolis flavone (EP–PF) and epimedium polysaccharide plus propolis extracts (EP–PE), were prepared and their immune-enhancing effects were compared. In test in vitro, the effects of them on chicken peripheral lymphocyte proliferation were determined by MTT method. The results showed that EP–PF group presented the highest stimulating index at most concentrations. In immune test, 300 14-day-old chickens were randomly divided into six groups and vaccinated with ND vaccine except for blank control (BC) group, re-challenged at 28 days of age. At the same time of the first vaccination, the chickens in four experimental groups were injected, respectively, with four prescriptions. The changes of the lymphocyte proliferation and antibody titer were determined. On day 28 after the first vaccination, the chickens except for BC group were challenged with NDV, the immune protective effect was observed. The results displayed that in EP–PF group, the antibody titers, lymphocyte proliferation and protective rate were the highest, the morbidity and mortality were the lowest. In dose test, 14-day-old chickens were randomly divided into five groups. The treatment and determinations were the same as the immune test except that the chickens in experimental groups were injected, respectively, with high, medium and low doses of EP–PF. The results revealed that in medium dose group, the antibody titers, lymphocyte proliferation and protective rate were the highest, the morbidity and mortality were the lowest. These results indicated that EP and PF possessed synergistically immune enhancement, EP–PF had the best efficacy, especially at medium dose, and would be expected to exploit into a new-type immunopotentiator.

Biological and Diurnal Variation in Glucocorticoid Sensitivity Detected with a Sensitivein VitroDexamethasone Suppression of Cytokine Production Assay

Glucocorticoid resistance due to mutations of the glucocorticoid receptor (NR3C1) are rare, but reduced glucocorticoid sensitivity may play a role in steroid-resistant asthma, inflammatory bowel disease, and septic shock. A rapid and sensitive functional assay to detect glucocorticoid resistance will be advantageous. We describe a rapid in vitro monocyte dexamethasone suppression of cytokine production (DSCP) assay with a 3-h incubation. The DSCP assay was compared with the reference stimulated lymphocyte proliferation method. We characterized the effect of delayed processing, time of sampling, and biological variation on the DSCP assay. The DSCP assay clearly distinguished subjects with a known heterozygous mutation of the NR3C1 gene from control subjects, whereas the reference method failed. Decreased glucocorticoid sensitivity was demonstrated in samples collected in the afternoon. Intra-individual variation from samples collected in the morning was 13.0 and 12.7% for the IL-6 and TNF-alpha responses with the respective inter-individual variations of 9.7 and 7.9%. The DSCP assay was superior to the reference method and was sufficiently sensitive to detect diurnal variation in control subjects. The biological variation data supported the use of a population-based reference interval. The assay is suitable for screening of glucocorticoid resistance phenotypes and may provide insight into cortisol metabolism in critically ill patients, asthmatics, and patients with inflammatory bowel disease provided that the variation due to delayed processing and time of collection are considered.

The Potential of Human Allogeneic Juvenile Chondrocytes for Restoration of Articular Cartilage

Background: Donor-site morbidity, limited numbers of cells, loss of phenotype during ex vivo expansion, and age-related decline in chondrogenic activity present critical obstacles to the use of autologous chondrocyte implantation for cartilage repair. Chondrocytes from juvenile cadaveric donors may represent an alternative to autologous cells. Hypothesis/Purpose: The authors hypothesized that juvenile chondrocyte would show stronger and more stable chondrogenic activity than adult cells in vitro and that juvenile cells pose little risk of immunologic incompatibility in adult hosts. Study Design: Controlled laboratory study. Methods: Cartilage samples were from juvenile (<13 years old) and adult (>13 years old) donors. The chondrogenic activity of freshly isolated human articular chondrocytes and of expanded cells after monolayer culture was measured by proteoglycan assay, gene expression analysis, and histology. Lymphocyte proliferation assays were used to assess immunogenic activity. Results: Proteoglycan content in neocartilage produced by juvenile chondrocytes was 100-fold higher than in neocartilage produced by adult cells. Collagen type II and type IX mRNA in fresh juvenile chondrocytes were 100- and 700-fold higher, respectively, than in adult chondrocytes. The distributions of collagens II and IX were similar in native juvenile cartilage and in neocartilage made by juvenile cells. Juvenile cells grew significantly faster in monolayer cultures than adult cells (P = .002) and proteoglycan levels produced in agarose culture was significantly higher in juvenile cells than in adult cells after multiple passages (P < .001). Juvenile chondrocytes did not stimulate lymphocyte proliferation. Conclusion: These results document a dramatic age-related decline in human chondrocyte chondrogenic potential and show that allogeneic juvenile chondrocytes do not stimulate an immunologic response in vivo. Clinical Relevance: Juvenile human chondrocytes have greater potential to restore articular cartilage than adult cells, and may be transplanted without the fear of rejection, suggesting a new allogeneic approach to restoring articular cartilage in older individuals.

Effects of perioperative immunonutrition on cell-mediated immunity, T helper type 1 (Th1)/Th2 differentiation, and Th17 response after pancreaticoduodenectomy

The mechanisms of immunonutrition on reducing infectious complications are still poorly understood. This prospective randomized study was designed to determine whether immunonutrition influences the following factors: cell-mediated immunity, differentiation of T helper type 1 (Th1) and Th2 cells, interleukin (IL)-17-producing CD4(+) helper T (Th17) cell response, and infectious complication rate after pancreaticoduodenectomy. Thirty patients who underwent pancreaticoduodenectomy were divided into 3 groups. Ten patients in the perioperative group received immune-enhancing diets enriched with arginine, omega-3 fatty acids, and RNA for 5 days before operative resection, which was prolonged after operative resection by enteral infusion. Ten patients in the postoperative group received early postoperative enteral infusion of the same enriched formula with no artificial nutrition before operative resection. Ten patients in the control group received total parenteral nutrition postoperatively. The primary endpoint was immune responses; the secondary endpoint was the rate of infectious complications. Concanavalin A (Con A)- or phytohemagglutinin (PHA)-stimulated lymphocyte proliferation and natural killer cell activity were significantly higher in the perioperative group than in the other groups. Messenger RNA (mRNA) expression levels of T-bet, interferon-gamma (IFN-gamma), related orphan receptor gammat (RORgammat), and interleukin-17F (IL-17F) were significantly higher in the perioperative group than in the other groups. In the perioperative group, the rate of infectious complications was significantly reduced compared with that in the other groups. Perioperative immunonutrition reduced stress-induced immunosuppression after a major stressful operative resection. The modulation of Th1/Th2 differentiation and Th17 response may play important roles in this immunologic effect.

Carrageenan from Solieria chordalis (Gigartinales): Structural analysis and immunological activities of the low molecular weight fractions

The investigations reported here are about a carrageenan extracted from the abundant red alga, Solieria chordalis (Gigartinales) settled along the coasts of Brittany. Its structural features were characterized by GC–MS, 13C NMR and FTIR spectroscopies. The structural components of this polysaccharide are mainly a (DA2S-G4S)-type structure in association with methylated-ι-carrageenan, pyruvated α-carrageenan and the minor precursor, ν-carrageenen, in small amounts. The relative molecular weight of the native polysaccharide was estimated by LP-GPC as 913 kDa. The low molecular weight fractions (below 20 kDa) obtained by free-radical depolymerization and mild-acid hydrolysis presented substitution patterns similar to those of the native polysaccharide. These fractions proved to be devoid of direct cytotoxicity on Daudi (human Burkitt's lymphoma), Jurkat (human leukaemic T-cell lymphoblast) and K562 (human chronic myelogenous leukaemia) cells lines. On the other hand, they showed great immunostimulating properties: enhancement of neutrophil phagocytosis, cytotoxicity by natural killer cells, antibody-dependent cell cytotoxicity and stimulation of lymphocyte proliferation. Further to these investigations, it could be worth using the low molecular weight fractions of carrageenan from the red alga, S. chordalis, in immunotherapeutic approaches to cancer treatment.

Immunomodulatory effects of betulinic acid from the bark of white birch on mice

The objective of this study was to explore the immunomodulatory effects of betulinic acid (BA) extracted from the bark of white birch on mice. Female mice were orally administered BA for 14 days in doses of 0, 0.25, 0.5, and 1 mg/kg body weight. We found that BA significantly enhanced the thymus and spleen indices, and stimulated lymphocyte proliferation induced by Concanavalin A and lipopolysaccharide as shown by MTT assay. Flow cytometry revealed that BA increased the percentage of CD4+ cells in thymus as well as the percentage of CD19+ and the ratios of CD4+/CD8+ in spleen. BA increased the number of plaque-forming cell and macrophage phagocytic activity as indicated by a neutral red dye uptake assay, and the peritoneal macrophages levels of TNF-α were also increased. In contrast, serum levels of IgG and IgM and serum concentrations of IL-2 and IL-6 were significantly decreased in BA-treated mice compared to the control as assayed by haemagglutination tests and ELISA, respectively. Taken together, these results suggest that BA enhances mouse cellular immunity, humoral immunity, and activity of macrophages. Thus, BA is a potential immune stimulator and may strengthen the immune response of its host.

The effect of β-glucans on porcine leukocytes

β-Glucans are conserved glucose polymers found in the cell walls of plants, fungi, yeasts and bacteria. They have the capacity to activate innate immunity, thereby enhancing defence barriers. Besides differences in type of linkage and branching, β-glucans can vary in solubility, molecular mass, tertiary structure, polymer charge and solution conformation. All these characteristics may influence their immunomodulating effects. In this study, the effect of seven β-glucans that differed in origin (fungi, yeast, seaweed, bacteria or algae) and structure (linear or branched; soluble, gel or particulate) were tested on peripheral blood mononuclear cells (PBMC) and neutrophils of the pig. We looked at lymphocyte proliferation, reactive oxygen species (ROS), production by neutrophils and monocytes and cytokine production. The soluble β-glucans Laminarin and Sleroglucan did not activate ROS-production of monocytes and neutrophils while the particulate β-glucans (β-glucan from algae ( Euglena gracilis)) and glucan preparations from baker's yeast (Macrogard, Saccharomyces cerevisiae and Zymosan) had a stimulating effect. The highest stimulation of lymphocyte proliferation occurred by Curdlan (bacteria), Zymosan and the β-glucan of E. gracilis, especially at high concentrations (200 μg/ml and 800 μg/ml). TNF-α was particularly stimulated by Macrogard and S. cerevisiae, while all β-glucans (except Laminarin) induced IL-1β. Furthermore, it was interesting that all β-glucans and in particular Curdlan, gave rise to IL-10 secretion, whereas any β-glucan induced the release of IL-8, IL-4, IL-12, IL-6 or IFN-γ.

Reciprocal effect of mesenchymal stem cell on experimental autoimmune encephalomyelitis is mediated by transforming growth factor-β and interleukin-6

Mesenchymal stem cells (MSCs) have the ability to suppress T cell proliferation and modulate cytokine production. Recently, MSCs have been shown to ameliorate autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE), but in some cases shown to stimulate lymphocyte proliferation. So far, mechanisms through which MSCs modulate immune reactions are still undefined. In this report we demonstrate that MSCs have the capacity for either stimulating or inhibiting myelin basic protein-specific T lymphocytes in a dose-dependent manner and modulate antigen-stimulated T cells to differentiate into either T helper type 17 or regulatory T cells, respectively, via pathways involving transforming growth factor-beta and interleukin-6. These results may lead better utility of MSCs as a treatment for autoimmune disease.

Suppression of Lymphocyte Proliferation and Regulation of Dendritic Cell Phenotype by Soluble Mediators from Rat Lacrimal Epithelial Cells

Lacrimal epithelial cells appear to constitutively secrete autoantigens to their underling stroma. The present experiments address the hypothesis that they also secrete soluble factors that regulate immune responses. Epithelial cells, spleen cells and lymphocytes were obtained from rabbits or rats and cultured in various configurations. Monocytes from rat bone marrow were matured to dendritic cells (DC) ex vivo. Proliferation was measured by [3H]-thymidine incorporation; surface MHC Class II and CD86 using flow cytometry; and mRNA relative abundances using real time RT-PCR. Microporous culture inserts containing rat lacrimal cells inhibited proliferation of rabbit lymphocytes co-cultured with autologous lacrimal cells and of rat lymphocytes co-cultured with TNF-alpha-stimulated DC. They inhibited CD86 and MHC Class II surface expression by maturating DC and reversed surface expression of CD86 but not MHC Class II by partially matured DC. Subsequent exposure of partially matured DC to mediators from rat lacrimal cells reversed the ability to stimulate lymphocyte proliferation. TGF-beta(1) and IL-10 mRNAs increased somewhat when rat lacrimal cells were isolated but decreased markedly in rabbit lacrimal cells. Antibodies to TGF-beta prevented soluble factors from rat lacrimal cells from inhibiting proliferation of rabbit lymphocytes co-cultured with rabbit lacrimal cells, but recombinant TGF-beta alone did not mimic the soluble factors. IL-10 immunopositivity was detected in epithelial cells of interlobular ducts and occasional interstitial cells in rabbit lacrimal gland. Rat lacrimal epithelial cells secrete TGF-beta and other factors that synergize to suppress lymphocyte proliferation and regulate DC maturation. Interlobular duct epithelial cells in rabbit lacrimal glands may express similar functions.

Effects of Rapamycin on the Differentiation and Function of Macrophages In Vitro

Macrophages have been generated from bone marrow progenitor cells (BMPCs) with macrophage colony-stimulating factor (M-CSF). Rapamycin (rapa) is an immunosuppressive drug, which could prevent renal graft rejection and inhibit tumor growth to yield antiproliferative activity in a variety of malignancies. However, the direct effect of rapa on the development of macrophages is unknown. In this study, we explored the direct effect of rapa on the differentiation and function of macrophages differentiated from mouse BMPCs in vitro in the presence of M-CSF. The experimental data showed that rapa prevented the differentiation of macrophages by down-regulating CD80 and CD86 expression but up-regulating F4/80 expression, as well as by reducing the capacity of differentiated macrophages to stimulate lymphocyte proliferation in the allogeneic mixed lymphocyte reaction. Furthermore, the phagocytic capacity of differentiated macrophages was significantly reduced by rapa. Therefore, rapa may directly inhibit macrophage differentiation and function, which may have been one of the major targets for rapa to mediate its immunosuppressive properties.

Characterization and anti-tumor activity of alkali-extracted polysaccharide from Enteromorpha intestinalis

The polysaccharide DAEB was isolated and purified from Enteromorpha intestinalis. It consisted of rhamnose, xylose, galactose, and glucose in a molar ratio of 5.36:1.00:0.57:0.64, and had a molecular weight of 46.8 kDa. Mice were treated with three doses of DAEB for 10 consecutive days by oral administration, the tumor inhibition was 61.17%, 67.65% and 70.59% at doses of 100, 200 and 400 mg/kg, respectively. However, no direct cytotoxicity was detected. At dose of 100, 200 and 400 mg/kg, a significant increase ( P < 0.01) in relative spleen and thymus weight, and production of tumor necrosis factor α (TNF-α) were observed in DAEB treated groups. We also found that DAEB significantly stimulated lymphocyte proliferation, especially Concanavalin A-induced lymphocyte proliferation in a dose-dependent manner, and augmented phagocytosis and secretion of NO and TNF-α in peritoneal macrophages. The results indicated that DAEB had potent anti-tumor activity which may be associated with its potent immunostimulating effect.

In vitro Effects of Methanol Extracts of Korean Medicinal Fruits (Persimmon, Raspberry, Tomato) on Chicken Lymphocytes, Macrophages, and Tumor Cells

A variety of fruits have traditionally been used in Asian cultures to enhance resistance to diseases and treat cancers. However, limited information exists on the underlying mechanisms responsible for these effects. The present investigation was conducted to examine the ability of three Korean indigenous fruits (persimmon, raspberry and tomato) to stimulate lymphocyte proliferation and macrophage nitric oxide production as parameters of innate immunity, and to inhibit tumor cell growth. In vitro co-culture of chicken spleen lymphocytes with methanol extracts of persimmon (Diospyros kaki) or tomato (Lycopersicon esculentum) induced greater cell proliferation compared with cells treated with the vehicle control. Stimulation of chicken macrophages with extracts of persimmon or raspberry (Rubus crataegifolius), but not tomato, stimulated robust nitric oxide production to levels similar to that produced by interferon-γ. All fruit extracts uniformly inhibited the growth chicken tumor cells in vitro. These results provide a rational basis for future studies investigating the effects of medicinal fruits on innate immunity and carcinogenesis in humans and animals.