Mitogen-induced Proliferation Research Articles

Assessing immune competence in pigs by immunization with tetanus toxoid

Immune competence can be tested by challenging organisms with a set of infectious agents. However, disease control requirements impose restrictions on the infliction of infections upon domestic pigs. Alternatively, vaccinations induce detectable immune responses that reflect immune competence. Here, we tested this approach with tetanus toxoid (TT) in young domestic pigs. To optimize the vaccination protocol, we immunized the pigs with a commercial TT vaccine at the age of 21 or 35 days. Booster immunizations were performed either 14 or 21 days later. TT-specific antibodies in plasma as well as lymphoproliferative responses were determined both 7 and 14 days after booster immunization using ELISA and lymphocyte transformation tests, respectively. In addition, general IgG and IgM plasma concentrations and mitogen-induced proliferation were measured. The highest TT-specific antibody responses were detected when blood samples were collected 1 week after a booster immunization conducted 21 days after primary immunization. The pigs’ age at primary immunization did not have a significant influence on TT-specific antibody responses. Similarly, the TT-specific proliferative responses were highest when blood samples were collected 1 week after booster immunization, while age and time of primary and booster immunization were irrelevant in our setup. While general IgG and IgM plasma levels were highly age dependent, there were no significant age effects for TT-specific immune responses. In addition, mitogen-induced proliferation was independent of immunization as well as blood sampling protocols. In summary, our model of TT vaccination provides an interesting approach for the assessment of immune competence in young pigs. The detected vaccination effects were not biased by age, even though our data were acquired from immune systems that were under development during our tests.

Loss of Spry1 attenuates vascular smooth muscle proliferation by impairing mitogen-mediated changes in cell cycle regulatory circuits.

Signals from growth factors or mechanical stimuli converge to promote vascular smooth muscle cell (VSMC) migration and proliferation, key events in the pathogenesis of intimal hyperplasia upon vascular injury. Spry1, a regulator of receptor tyrosine kinases (RTK), plays a role in maintaining the contractile phenotype of VSMC. The aim of the current study was to determine the role of Spry1 in VSMC proliferation in vitro and injury induced neointimal hyperplasia in vivo. VSMC proliferation and neointima formation were evaluated in cultured human aortic SMC (hAoSMC) and ligation-induced injury of mouse carotid arteries from Spry1 gene targeted mice, and their corresponding wild type littermates. Human Spry1 or non-targeting control lentiviral shRNAs were used to knock down Spry1 in hAoSMC. Time course cell cycle analysis showed a reduced fraction of S-phase cells at 12 and 24 h after growth medium stimulation in Spry1 shRNA transduced hAoSMC. Consistent with reduced S-phase entry, the induction of cyclinD1 and the levels of pRbS807/S811, pH3Ser10, and pCdc2 were also reduced, while the cell cycle inhibitor p27Kip1 was maintained in Spry1 knockdown hAoSMC. In vivo, loss of Spry1 attenuated carotid artery ligation-induced neointima formation in mice, and this effect was accompanied by a decrease in cell proliferation similar to the in vitro results. Our findings demonstrate that loss of Spry1 attenuates mitogen-induced VSMC proliferation, and thus injury-induced neointimal hyperplasia likely via insufficient activation of Akt signaling causing decreased cyclinD1 and increased p27Kip1 and a subsequent decrease in Rb and cdc2 phosphorylation.

Immunomodulatory constituents from Ascomycetous fungi.

Our screening project, namely, search for new immunomodulatory constituents from Ascomycetous fungi, was guided by the effects on mitogen-induced proliferations of mouse spleen lymphocytes. On the project, the defatted crude extracts from Gelasinospora multiforis, G. heterospora, G. longispora, G. kobi, Diplogelasinospora grovesii, Emericella aurantio-brunnea, Eupenicillium crustaceum, etc., submitted to the solvent partition followed by fractionation with repeated chromatography monitored by immunomodulatory activity to afford many active constituents, of which molecular structures including absolute configurations and immunomodulatory activities were elucidated. All of these immunomodulatory constituents isolated on the project were practically not immunostimulants but immunosuppressants.

Certain biological properties of multipotent mesenchymal stromal cells from bone marrow and adipose tissue of FVB/N mice

Multipotent mesenchymal stromal cells (MMSCs) are used for cell therapy of lesions of various genesis. The most widely used MMSCs are from two tissue sources: bone marrow and adipose tissue.The purpose of the work was to conduct a comparative assessment of the biological properties of murine bone marrow-derived and adipose tissue-derived MMSCs.Methods. The culture of MMSCs was obtained from the bone marrow and adipose tissue of 6 months-old male FVB/N mice according to standard protocols. We performed phenotyping, directed osteogenic and adipogenic differentiation, analysis of immunomodulatory properties in vitro of obtained cell cultures.Results. The cultured MMSCs from bone marrow and adipose tissue express the typical stromal markers (CD44, CD73, CD90 and Sca-1). A distinctive feature of bone marrow cells cultures of the 2nd passage was the high level of the hematopoietic markers CD45 and CD117 expression. MMSCs from both tissue sources are capable of differentiation in the osteogenic and adipogenic directions. At the same time, there were differences in the differentiation in the osteogenic direction – adipose tissue-derived MMSCs had a lower osteogenic potential. MMSCs exhibit inhibitory effect on mitogen-induced proliferation of splenocytes in vitro, expression of which does not depend on tissue origin of the MMSCs with significant inhibition of mitogen-induced proliferation of splenocytes at addition of high doses of MMSCs.Conclusions. MMSCs of bone marrow and adipose tissue express a similar level of surface markers that are characteristic of cells with multipotent properties. They are capable to differentiating in osteo- and adipogenic direction with differences in the degree of mineralization of the extracellular matrix and exhibit immunomodulatory effects in vitro, regardless of tissue origin.

Lipopolysaccharide levels adherent to PM2.5 play an important role in particulate matter induced-immunosuppressive effects in mouse splenocytes.

Epidemiological studies show that exposure to ambient particulate matter (PM) is associated with serious adverse health effects, including, but not limited to, those on the respiratory system. In the present study, we investigated the splenic response in mice administered PM of ≤ 2.5 μ m diameter (PM2.5). Male BALB/c mice (7 or 8 weeks old) were intratracheally administered PM2.5 (0.1mg) four times, at 2week intervals, and dissected 24h after the final administration. The effect of six types of PM2.5, collected in Shenyang or Beijing (China) and Kitakyushu (Japan), on splenocytes was examined. Our results revealed a strong correlation between the levels of lipopolysaccharide (LPS), but not that of β-glucan and polycyclic aromatic hydrocarbons, attached to PM2.5 and the effect of PM2.5 on cell activity. PM2.5 with a low amount of LPS (PM2.5LL) reduced splenocyte mitogen-induced proliferation and cytokine production compared with that in control mice. The suppressive effects of PM2.5LL on proliferation and interleukin-2 production in splenocytes were rescued by the antioxidant N-acetylcysteine. Expression of heme oxygenase-1 was elevated after PM2.5LL administration, particularly in CD11b+ cells, while no elevation was observed in CD4+ , CD8+ or B220+ cells. Further, dissociation of the nuclear factor erythroid 2-related factor 2 from Kelch-like ECH-associating protein 1 was observed in splenocytes of PM2.5LL-administered mice. These data suggest that LPS attached to PM2.5 modulates the splenocyte immune responses to PM2.5.

Immunoenhancement Effects of Glycosaminoglycan from Apostichopus japonicus: In Vitro and In Cyclophosphamide-Induced Immunosuppressed Mice Studies.

In this study, the immunomodulatory activities of Apostichopus japonicus glycosaminoglycan (AHG) on the nature killer (NK) cells, cytotoxic T lymphocytes (CTLs) and cyclophosphamide (CY)-treated mice were investigated. After stimulation with multiple concentrations of AHG (0–100 μg/mL), NK cells and CTLs displayed outperformance against YAC-1 and B16 cells, respectively. Furthermore, the mitogen-induced splenic lymphocyte proliferation in CY-induced immunosuppressed mice was significantly promoted by AHG. In addition, the administration of AHG dramatically increased the splenocytes Ca2+ concentration and the delayed-type hypersensitivity (DTH) reaction in a dose-dependent manner. Besides, AHG could strongly increase the total antioxidant capacity (T-AOC), the activities of superoxidase dismutase (SOD), catalase (CAT) as well as glutathione peroxidase (GSH-PX), and could decrease the malondialdehyde (MDA) level in the heart, kidney and liver. These findings indicated that AHG played an important role in the immune enhancement and protection against CY-induced immunosuppression and oxidative damage. Our findings provide experimental evidence for further research and possible immunostimulatory applications of AHG in clinical practice.

Fluoxetine Treatment in Rats Increases the Rate of Taurine Transport in Mononuclear Cells

Fluoxetine, a selective serotonin reuptake inhibitor antidepressant, modulates the mitogen-induced proliferation of lymphocytes. Lymphocytes contain taurine and express taurine transporter (TauT). Among the effects of taurine on lymphocytes are protection against oxidants and regulation of the inflammatory aspects of the immune response. Our aim was to determine the influence of fluoxetine treatment on taurine transport, and to determine the presence of TauT in the mononuclear cells of rats. Methods: Male adult Sprague-Dawley rats were treated with fluoxetine 10 mg/kg i.p. for 1, 2, and 3 weeks. The cells were obtained by density gradients. [³H]Taurine was used for transport assays. Amino acid levels were determined by high-performance liquid chromatography. Immunolabeling of CD4+, CD8+, and TauT was performed. The mRNA of TauT was evaluated by RT-PCR. Controls were included for each protocol. Results: The transport of taurine, after 1 week of treatment, was significantly augmented compared to controls. The affinity significantly increased at 1 and 2 weeks. While the percentage of CD4+ cells decreased and that of CD8+ cells increased, the percentage of TauT in CD4+ and CD8+ cells was not affected. Reduction of levels of aspartic acid, glutamic acid, threonine, alanine, glycine, and arginine occurred at 1 and 2 weeks. The taurine concentration significantly decreased after 2 and 3 weeks of treatment. The estimation of mRNA of TauT was not different. Conclusion: Taurine transport increases with fluoxetine treatment, and so this could be related to an immunomodulatory role of fluoxetine through TauT. Inhibition of serotonin reuptake might be involved in the regulation of taurine transport in mononuclear cells.

Spores of two probiotic Bacillus species enhance cellular immunity in BALB/C mice

Previous studies found that Bacillus subtilis BS02 and B. subtilis subsp. natto BS04 isolated in our laboratory could activate the immune response of murine macrophages in vitro. This study aims to investigate the effects of dietary supplementation with Bacillus species spores on the systemic cellular immune response in BALB/C mice. Results showed that both B. subtilis BS02 and B. subtilis natto BS04 enhanced the phagocytic function of the mononuclear phagocyte system (MPS) and the cytotoxicity of natural killer (NK) cells. In addition, B. subtilis BS02 could increase the respiratory burst activity of blood phagocytes. Furthermore, B. subtilis BS02 and B. subtilis natto BS04 increased the percentage of gamma-interferon-producing CD4+ cells and CD8+ T-cells, but only BS04 increased the percentage of CD3+ cells and CD3+ CD4+ cells in splenocytes. However, there were no effects on other subsets of splenic lymphocytes and mitogen-induced splenic lymphocyte proliferation. All data suggested that oral administration of B. subtilis BS02 or B. subtilis natto BS04 could significantly enhance cellular immunity in BALB/C mice by increasing phagocytic activity of MPS and cytotoxic activity of NK cells in a strain-specific manner.

Trigonostemon reidioides modulates endothelial cell proliferation, migration and tube formation via downregulation of the Akt signaling pathway.

Trigonostemon reidi`oides (TR) is used as a Thai traditional medicine for the treatment of drug addiction, asthma, food poisoning, constipation and snake bites. The present study investigated the effects and molecular mechanisms of the ethanolic extract of TR (ETR) on mitogen-induced human umbilical vein endothelial cells (HUVECs) responses, proliferation, adhesion, migration and tube formation. ETR treatment inhibited mitogen-induced HUVEC proliferation by downregulation of cell cycle-associated proteins, including cyclins and cyclin-dependent kinases, which induced retinoblastoma protein hypophosphorylation. The present study also demonstrated that ETR treatment suppressed mitogen-induced HUVEC adhesion, migration, invasion and tube formation, and that these anti-angiogenic activities were mediated by inactivation of mitogen-induced Akt and matrix metalloproteinase (MMP)-2, but not of extracellular signal-regulated kinase, p70 ribosomal S6 kinase or MMP-9. Collectively, the results of the present study suggested pharmacological functions and molecular mechanisms of ETR in regulating endothelial cell fates, and supported further evaluation and development of ETR as a potential therapeutic agent for the treatment and prevention of angiogenesis-associated diseases, including cancer.

Effect of inhibiting the lactogenic signal at calving on milk production and metabolic and immune perturbations in dairy cows

During the periparturient period, the abrupt increase in energy demand for milk production often induces metabolic and immunological disturbances in dairy cows. Our previous work has shown that reducing milk output by milking once a day or incompletely in the first few days of lactation reduces these disturbances. The aim of this study was to reduce metabolic and immunological disturbances by limiting milk production during the first week of lactation by inhibiting the lactogenic signal driven by prolactin. Twenty-two fresh cows received 8 i.m. injections of the prolactin-release inhibitor quinagolide (QUIN; 2 mg) or water as a control (CTL). The first injection was given just after calving, and the subsequent 7 injections were given every 12 h. Milk production was measured until d 28 after calving. Blood samples were taken from d 1 (calving) to d 5 and then on d 7, 10, 14, 21, and 28 to measure concentrations of urea, phosphorus, calcium, glucose, nonesterified fatty acids (NEFA), β-hydroxybutyrate, and prolactin. Other blood samples were taken on d 2, 5, 10, and 28 to analyze oxidative burst, phagocytosis, and the effect of the serum on the lymphoproliferation of peripheral blood mononuclear cells from donor cows. Blood prolactin concentration was lower from d 2 to 5 but higher from d 10 to 28 in the QUIN cows than in the CTL cows. Milk production was lower from d 2 to 6 in the QUIN cows than in the CTL cows (24.3 ± 6.4 and 34.8 ± 4.1 kg/d on average, respectively). We observed no residual effect of quinagolide on milk production after d 6. During the first week of lactation, blood glucose and calcium concentrations were higher and β-hydroxybutyrate concentration was lower in the QUIN cows than in the CTL cows. Blood NEFA, urea, and phosphorus concentrations were not affected by the treatment. At d 2 and 5, the phagocytosis ability of polymorphonuclear leukocytes was not affected by treatment; however, quinagolide injection enhanced the proportion of cells that entered oxidative burst, The mitogen-induced proliferation of peripheral blood mononuclear cells was greater when they were incubated with serum harvested from the CTL cows and was negatively correlated with the NEFA concentration in the serum. Reducing the prolactin peak at calving was effective in reducing milk production during the first week of lactation without compromising the dairy cow's overall productivity. Slowing the increase in milk production allowed a more gradual transition from pregnancy to lactation and led to a reduction in metabolic stress and an improvement in some immune system aspects during this period.

Modeling Combined Immunosuppressive and Anti-inflammatory Effects of Dexamethasone and Naproxen in Rats Predicts the Steroid-Sparing Potential of Naproxen.

Dexamethasone (DEX), a widely prescribed corticosteroid, has long been the cornerstone of the treatment of inflammation and immunologic dysfunctions in rheumatoid arthritis. Corticosteroids are frequently used in combination with other antirheumatic agents such as nonsteroidal anti-inflammatory drugs (NSAIDs) and disease-modifying antirheumatic drugs to mitigate disease symptoms and minimize unwanted effects. We explored the steroid dose-sparing potential of the NSAID naproxen (NPX) with in vitro and in vivo studies. The single and joint suppressive effects of DEX and NPX on the in vitro mitogen-induced proliferation of T lymphocytes in blood and their anti-inflammatory actions on paw edema were investigated in female and male Lewis rats with collagen-induced arthritis (CIA). As expected, DEX was far more potent than NPX in these systems. Mathematical models incorporating an interaction term ψ were applied to quantitatively assess the nature and intensity of pharmacodynamic interactions between DEX and NPX. Modest synergistic effects of the two drugs were found in suppressing the mitogenic response of T lymphocytes. A pharmacokinetic/pharmacodynamic/disease progression model integrating dual drug inhibition quantitatively described the pharmacokinetics, time-course of single and joint anti-inflammatory effects (paw edema), and sex differences in CIA rats, and indicated additive effects of DEX and NPX. Further model simulations demonstrated the promising steroid-sparing potential of NPX in CIA rats, with the beneficial effects of the combination therapy more likely in males than females.

Myeloid-derived suppressor cells can be efficiently generated from human hematopoietic progenitors and peripheral blood monocytes.

Myeloid-derived suppressor cells (MDSCs) have an important role in controlling inflammation. As such, they are both a therapeutic target and, based on the administration of ex vivo-generated MDSCs, a therapeutic tool. However, there are relatively few reports describing methods to generate human MDSCs, and most of them rely on cells obtained from peripheral blood monocytes. We investigated alternative approaches to the generation of MDSCs from hematopoietic progenitors and monocytes. Purified CD34+ hematopoietic progenitors from apheresis products and CD14+ cells isolated from buffy coats were cultured in the presence of different combinations of cytokines. The resulting myeloid cell populations were then characterized phenotypically and functionally. Progenitor cells cultured in the presence of SCF+TPO+FLT3-L+GM-CSF+IL-6 gave rise to both monocytic (M)- and granulocytic (G)-MDSCs but production of the latter was partially inhibited by IL-3. M-MDSCs but not G-MDSCs were obtained by culturing peripheral blood monocytes with GM-CSF+IL-6 or GM-CSF+TGF-β1 for 6 days. CD14 expression was downregulated in the cultured cells. PD-L1 expression at baseline was lower in hematopoietic progenitor cell-derived than in monocyte-derived MDSCs, but was markedly increased in response to stimulation with LPS+IFN-γ. The functionality of the two MDSC subtypes was confirmed in studies of the suppression of allogeneic and mitogen-induced proliferation and by cytokine profiling. Here we describe both the culture conditions that allow the generation of MDSCs and the phenotypical and functional characterization of these cell populations.

Glycerol Monolaurate (GML) Inhibits Human T Cell Signaling, Metabolism, and Function By Disrupting Lipid Dynamics

Glycerol Monolaurate (GML) is a naturally occurring fatty acid widely utilized in food, cosmetics, and homeopathic supplements. GML is a potent antimicrobial agent that targets a range of bacteria, fungi, and enveloped viruses. Interestingly, GML suppresses mitogen induced lymphocyte proliferation and inositol triphosphate production, suggesting that GML has immunomodulatory functions. In this study, we have mechanistically examined if GML affects the signaling, metabolism, and functional output of human primary T cells. We found that GML potently altered lipid order and disorder dynamics in the plasma membrane that resulted in reduced membrane localized clustering of the proteins LAT, PLC-γ, and AKT, events integral for proper T cell receptor (TCR) signal propagation. Altered membrane signaling events induced selective inhibition of TCR-induced phosphorylation of SLP-76, regulatory P85 subunit of PI3K, and AKT as well as abrogated calcium influx. In addition to signaling defects, GML treated cells have profoundly altered metabolism profiles characterized by suppressed oxidative phosphorylation and increased glycolysis. Functionally, GML treatment potently reduced TCR-induced production of the cytokines IL-2, IFN-γ, TNF-α, and IL-10. Our data reveal that the widely used anti-microbial agent GML alters the lipid dynamics of human T cells, leading to their defective signaling, metabolism, and function.

Immune Dysfunction After Completion of Childhood Leukemia Therapy.

Children with leukemia suffer immune dysfunction from their malignancy and chemotherapy. The immune system components most affected, the degree to which immune suppression occurs, and the duration of immunodeficiency are incompletely characterized. This study measures immunologic parameters following completion of therapy. This is a prospective, single institution cohort study. Eligible children with acute myelogenous or acute lymphoblastic leukemia diagnosed between 1 and 21 years of age were enrolled at therapy completion. Immune parameters were assessed at the end of therapy and 6 months later: complete blood counts, immunoglobulin levels, quantitative lymphocyte subsets, mitogen-induced lymphocyte proliferation, natural killer cell function, and vaccine titers. Twenty patients were evaluated; 13 (65%) were female, 15 had acute lymphoblastic leukemia (75%). Mean age at diagnosis was 7.9 years. At end of therapy, all patients had some degree of immune dysfunction. At 6 months posttherapy, persistent abnormalities included: leukopenia (25%), neutropenia (15%), lymphopenia (5%), hypogammaglobulinemia (25%), one or more subtherapeutic vaccine titers (100%), abnormal lymphocyte subset levels (20%), decreased (15%), or absent (10%) natural killer cell function and abnormal lymphocyte proliferative responses (25%). All patients had multiple abnormalities at end of therapy, and all patients had some degree of persistent immune dysfunction at 6 months after completion of therapy. Clinical implications of these laboratory abnormalities are currently unknown; longer term evaluations are ongoing. We demonstrate that survivors of childhood cancer have lasting quantitative and functional immunologic defects and may remain at risk for infectious complications after completion of therapy.

Exercise Affects T-Cell Function by Modifying Intracellular Calcium Homeostasis.

The study aimed to investigate the effects of chronic moderate exercise on regulation of intracellular calcium signaling as an important link to proliferation capacity in murine splenic T lymphocytes. Male CD1 Swiss mice were randomly assigned either to a control group (CG) or an exercise training group (EG). EG mice performed voluntary exercise for 3 months. Lymphocytes were isolated from murine spleens and intracellular calcium was determined by using Fura-2(AM) and fluorescence spectrometry. The combination of flow cytometry and carboxy-fluorescein succinimidyl ester labeling technique was used for determination of cell proliferation. The expression levels of Ca-regulating genes were determined by quantitative polymerase chain reaction (qPCR) analysis. Basal [Ca]i was significantly higher in mice from the EG compared with mice of the CG (P < 0.001, n = 6). Similarly, [Ca]i transients after stimulation with phytohemagglutinin, concanavalin A, and the anti-CD3 antibody induced were significantly increased in mice from the EG (P < 0.05, n = 5). However, no differences were found after stimulation with thapsigargin (P < 0.05, n = 5). CD3 T cells from EG showed higher mitogen-induced proliferation levels than from CG (P < 0.05/0.01, n = 5). The mRNA expression of cellular Ca-regulating genes, such as STIM1, Cav2.3, TRPV4, IP3R2, ORAI1, MCU, TRPM5, and TRPC1, were significantly downregulated (P < 0.05/0.01, n = 5). This study suggests that chronic moderate exercise improves intracellular Ca signaling in murine splenic lymphocytes. The enhanced availability of the second messenger Ca is followed by an improved cellular function such as cell proliferation. The downregulation of Ca homeostasis-related factor expression might be considered as a self-protective mechanism against elevated intracellular Ca signals.

Clozapine-induced agranulocytosis: Evidence for an immune-mediated mechanism from a patient-specific in-vitro approach

Use of the atypical antipsychotic clozapine (CZP) is compromised by the risk of potentially fatal agranulocytosis/granulocytopenia (CIAG). To address this, we have established a simple, personalized cell culture-based strategy to identify CIAG-susceptible patients, hypothesizing that an immunogenic and possibly haptene-based mechanism underlies CIAG pathophysiology.To detect a putative haptene-induced response to CZP in vitro exposure, a traditional lymphocyte stimulation assay was adapted and applied to patient-specific peripheral blood-derived mononuclear cells (PBMC). 6 patients with a history of CIAG, 6 patients under CZP treatment (without CIAG) and 12 matched healthy controls were studied.In vitro CZP exposure, even at strikingly low levels, resulted in significantly increased proliferation rates only in CIAG patients' PBMC. Other parameters including cell viability and mitogen-induced proliferation were also affected by in vitro CZP exposure, yet there was no significant difference between the groups.This personalized approach is a starting point for further investigations into a putative haptene-based mechanism underlying CIAG development, and may facilitate the future development of predictive testing.

5‐Amino‐3‐methyl‐4‐isoxazolecarboxylic acid hydrazide derivatives with in vitro immunomodulatory activities

Isoxazoles are an important class of compounds of potential therapeutic value. The aim of this study was to determine immunotropic effects of 5-amino-3-methyl-4-isoxazolecarboxylic acid hydrazide derivatives on spontaneous and mitogen-induced lymphocyte proliferation in young and old mice, cytokine production by peritoneal cells as well as possible mechanism of action in a model of Jurkat cells. Three-month-old and 13-month-old BALB/c mice were used as donors of the cells from a thymus, a spleen, mesenteric lymph nodes, and a peritoneal cavity. Spontaneous and concanavalin A or lipopolysaccharide (LPS)-induced cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric method. IL-1β and TNF-α production induced by LPS in macrophage-enriched peritoneal cell cultures was measured by enzyme-linked immunoassay. 5-amino-3-methyl-4-isoxazolecarboxylic acid hydrazide, 01K (4-phenyl-1-(5-amino-3-methylisoxazole-4-carbonyl)-thiosemicarbazide), and 06K (4-(4-chlorophenyl)-1-(5-amino-3-methylisoxazole-4-carbonyl)-thiosemicarbazide) exhibited regulatory activity in the proliferation tests. Prevailing stimulatory activity of the hydrazide and inhibitory activity of 01K and 06K was observed. Those effects were connected with different influence of the compounds on signaling proteins expression in Jurkat cells. The regulatory effects of the compounds on IL-1β production were more profound than those on TNF-α. Differences in the compound activity in young versus old mice were mainly restricted to 01K. Immunosuppressive isoxazole leflunomide and a stimulatory RM-11 (1,7-dimethyl-8-oxo-1,2H-isoxazole [5,4-e]triazepine) were applied as reference drugs.

Immunomodulatory and cellular anti-oxidant activities of caffeic, ferulic, and p-coumaric phenolic acids: a structure–activity relationship study

Many studies have been performed to assess the potential utility of natural products as immunomodulatory agents to enhance host responses and to reduce damage to the human body. To determine whether phenolic compounds (caffeic, ferulic, and p-coumaric acids) have immunomodulatory effects and clarify which types of immune effector cells are stimulated in vitro, we evaluated their effect on splenocyte proliferation and lysosomal enzyme activity. We also investigated the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL). In addition, induction of the cellular antioxidant activity in splenocytes, macrophages, and red blood cells was determined by measuring the fluorescence of the DCF product. The study first results indicated that caffeic, ferulic, and p-coumaric acids significantly promote LPS-stimulated splenocyte proliferation, suggesting a potential activation of B cells, and enhanced humoral immune response in hosts treated by the tested natural products. Phenolic acids significantly enhanced the killing activity of isolated NK and CTL cells but had negligible effects on mitogen-induced proliferation of splenic T cells. We showed that caffeic acid enhances lysosomal enzyme activity in murine peritoneal macrophages, suggesting a potential role in activating such cells. Immunomodulatory activity was concomitant with the cellular antioxidant effect in macrophages and splenocytes of caffeic and ferulic acids. We conclude from this study that caffeic, ferulic, and p-coumaric acids exhibited an immunomodulatory effect which could be ascribed, in part, to their cytoprotective effect via their antioxidant capacity. Furthermore, these results suggest that these natural products could be potentially used to modulate immune cell functions in physiological and pathological conditions.

Extracellular Vesicles Released from Human Umbilical Cord-Derived Mesenchymal Stromal Cells Prevent Life-Threatening Acute Graft-Versus-Host Disease in a Mouse Model of Allogeneic Hematopoietic Stem Cell Transplantation.

Mesenchymal stromal cells (MSCs) are attractive agents for the prophylaxis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, safety concerns remain about their clinical application. In this study, we explored whether extracellular vesicles released from human umbilical cord-derived MSCs (hUC-MSC-EVs) could prevent aGVHD in a mouse model of allo-HSCT. hUC-MSC-EVs were intravenously administered to recipient mice on days 0 and 7 after allo-HSCT, and the prophylactic effects of hUC-MSC-EVs were assessed by observing the in vivo manifestations of aGVHD, histologic changes in target organs, and recipient mouse survival. We evaluated the effects of hUC-MSC-EVs on immune cells and inflammatory cytokines by flow cytometry and ProcartaPlex™ Multiplex Immunoassays, respectively. The in vitro effects of hUC-MSC-EVs were determined by mitogen-induced proliferation assays. hUC-MSC-EVs alleviated the in vivo manifestations of aGVHD and the associated histologic changes and significantly reduced the mortality of the recipient mice. Recipients treated with hUC-MSC-EVs had significantly lower frequencies and absolute numbers of CD3+CD8+ T cells; reduced serum levels of IL-2, TNF-α, and IFN-γ; a higher ratio of CD3+CD4+ and CD3+CD8+ T cells; and higher serum levels of IL-10. An in vitro experiment demonstrated that hUC-MSC-EVs inhibited the mitogen-induced proliferation of splenocytes in a dose-dependent manner, and the cytokine changes were similar to those observed in vivo. This study indicated that hUC-MSC-EVs can prevent life-threatening aGVHD by modulating immune responses. These data provide the first evidence that hUC-MSC-EVs represent an ideal alternative in the prophylaxis of aGVHD after allo-HSCT.

Immunotoxic effects of gold and silver nanoparticles: Inhibition of mitogen-induced proliferative responses and viability of human and murine lymphocytes in vitro

Understanding the effects of nanoparticles (NP) on immune cell functions is essential in designing safe and effective NP-based in vivo drug delivery systems. The immunomodulatory potential of gold nanoparticles (GNP) and silver nanoparticles (SNP) was investigated in vitro using murine splenic and human peripheral blood lymphocytes (PBL) in terms of effects on viability and mitogen-induced proliferation. Hydrodynamic size and number of NP were characterized using NP tracking analysis (NTA); modal diameters of GNP and SNP were 28 (±1.5) and 66 (± 2.7) nm, respectively, with a unimodal distribution. Lymphocytes were incubated with GNP or SNP in the presence/absence of B- or T-cell mitogens and proliferative responses then determined using [3H]-thymidine incorporation. Concanavalin A (T-cell-specific) and lipopolysaccharide- (B-cell-specific) stimulated responses of murine splenic lymphocytes, as well as phytohemagglutinin (T-cell-specific) and pokeweed mitogen- (B-and T-cell specific) induced responses of human lymphocytes, were significantly inhibited by GNP (25–200 μg/ml) and SNP (12.5–50 μg/ml). However, [3H]-thymidine incorporation by unstimulated lymphocytes was unaffected in the presence of GNP or SNP. Viability of lymphocytes was determined using trypan blue dye exclusion and was significantly inhibited only at 200 μg GNP/ml and 25 or 50 μg SNP/ml. As mitogen responses are most useful to provide supportive mechanistic information on primary immunotoxicologic functional observations, and so far more comprehensive data (in vivo and in vitro) is still needed, the results nevertheless suggest to us that GNP and SNP might potentially be able to modulate immune responses by impacting on lymphocyte activation.