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At least 487 records · Page 27Linked to original sources

Human mesenchymal stem cells modulate allogeneic immune cell responses.

Mesenchymal stem cells (MSCs) are multipotent cells found in several adult tissues. Transplanted allogeneic MSCs can be detected in recipients at extended time points, indicating a lack of immune recognition and clearance. As well, a role for bone marrow-derived MSCs in reducing the incidence and severity of graft-versus-host disease (GVHD) during allogeneic transplantation has recently been reported; however, the mechanisms remain to be investigated. We examined the immunomodulatory functions of human MSCs (hMSCs) by coculturing them with purified subpopulations of immune cells and report here that hMSCs altered the cytokine secretion profile of dendritic cells (DCs), naive and effector T cells (T helper 1 [T(H)1] and T(H)2), and natural killer (NK) cells to induce a more anti-inflammatory or tolerant phenotype. Specifically, the hMSCs caused mature DCs type 1 (DC1) to decrease tumor necrosis factor alpha (TNF-alpha) secretion and mature DC2 to increase interleukin-10 (IL-10) secretion; hMSCs caused T(H)1 cells to decrease interferon gamma (IFN-gamma) and caused the T(H)2 cells to increase secretion of IL-4; hMSCs caused an increase in the proportion of regulatory T cells (T(Regs)) present; and hMSCs decreased secretion of IFN-gamma from the NK cells. Mechanistically, the hMSCs produced elevated prostaglandin E2 (PGE(2)) in co-cultures, and inhibitors of PGE(2) production mitigated hMSC-mediated immune modulation. These data offer insight into the interactions between allogeneic MSCs and immune cells and provide mechanisms likely involved with the in vivo MSC-mediated induction of tolerance that could be therapeutic for reduction of GVHD, rejection, and modulation of inflammation.

Cell Communication↗

Noradrenaline modulates the immunity of white shrimp Litopenaeus vannamei.

The total haemocyte count (THC), phenoloxidase activity, respiratory burst, superoxide dismutase (SOD) activity, phagocytic activity and clearance efficiency in response to pathogen Vibrio alginolyticus were measured when the white shrimp Litopenaeus vannamei (18.4 +/- 1.2 g) were injected individually with noradrenaline at 10(-8), 10(-7) and 10(-6) mol shrimp(-1). For the shrimp that received noradrenaline at 10(-8), 10(-7) and 10(-6) mol shrimp(-1), the THC decreased by 15%, 21% and 32%, phenoloxidase activity decreased by 15%, 31% and 31%, respiratory burst decreased by 13%, 21% and 32%, and SOD activity decreased by 46%, 56% and 55%, respectively, after 2 h. The phagocytic activity and clearance efficiency of shrimp that received noradrenaline at either dose decreased significantly after 2 h. The THC, phenoloxidase activity, respiratory burst, SOD activity, phagocytic activity and clearance efficiency returned to normal values after 4, 4, 8, 24, 16 and 8 h, respectively, in the shrimp that received noradrenaline at either dose. In another experiment, L. vannamei which had received noradrenaline at 10(-8), 10(-7) and 10(-6) mol shrimp(-1) were challenged after 1h by injection with V. alginolyticus at 1.0 x 10(5) colony-forming units (cfu)shrimp(-1) and then placed in seawater of 20 per thousand. The cumulative mortality of shrimp that received noradrenaline at either dose was significantly higher than that of shrimp that received saline after 4 h, and at the termination of the experiment (48 h after the challenge). It is therefore concluded that noradrenaline administration at 10(-6) mol shrimp(-1) or less causes immune modulation of L. vannamei.

Animals↗

Inhibition of the cyclic AMP signaling cascade and nuclear factor binding to CRE and kappaB elements by cannabinol, a minimally CNS-active cannabinoid.

Immune suppression by cannabinoids has been widely demonstrated in a variety of experimental models. The identification of two major types of G-protein-coupled cannabinoid receptors expressed on leukocytes, CB1 and CB2, has provided a putative mechanism of action for immune modulation by cannabinoid compounds. Ligand binding to both receptors negatively regulates adenylate cyclase, thereby lowering intracellular cyclic AMP (cAMP) levels. In the present studies, we demonstrated that cannabinol (CBN), a ligand that exhibits higher binding affinity for CB2, modulates immune responses and cAMP-mediated signal transduction in mouse lymphoid cells. Direct addition of CBN to naive cultured splenocytes produced a concentration-dependent inhibition of lymphoproliferative responses to anti-CD3, lipopolysaccharide, and phorbol-12-myristate-13-acetate/ionomycin stimulation. Similarly, a concentration-related inhibition of the in vitro anti-sheep red blood cell IgM antibody forming cell response was also observed by CBN. Evaluation of cAMP signaling in the presence of CBN showed a rapid and concentration-related inhibition of adenylate cyclase activity in both splenocytes and thymocytes. This decrease in intracellular cAMP levels produced by CBN resulted in a reduction of protein kinase A activity, consequently leading to an inhibition of transcription factor binding to the cAMP response element and kappaB motifs in both cell preparations. Collectively, these results demonstrate that CBN, a cannabinoid with minimal CNS activity, inhibited both cAMP signal transduction and immune function, further supporting the involvement of CB2 receptors in immune modulation by cannabimimetic agents.

Activating Transcription Factor 2↗

Prostaglandins as modulators of immunity.

Prostaglandins are potent lipid molecules that affect key aspects of immunity. The original view of prostaglandins was that they were simply immunoinhibitory. This review focuses on recent findings concerning prostaglandin E2 (PGE2) and the PGD2 metabolite 15-deoxy-Delta(12,14)-PGJ2, and their divergent roles in immune regulation. We will highlight how these two seminal prostaglandins regulate immunity and inflammation, and play an emerging role in cancer progression. Understanding the diverse activities of these prostaglandins is crucial for the development of new therapies aimed at immune modulation.

Adjuvants, Immunologic↗

The tetraspanin web modulates immune-signalling complexes.

The tetraspanin web represents a new concept of molecular interactions in the immune system. Whereas most surface immune-modulating molecules involve receptor-ligand interactions, tetraspanins associate with partner proteins and facilitate their lateral positioning in the membrane. Moreover, the same tetraspanin molecule can associate with different proteins depending on the cell type. Most importantly, members of this family tend to associate with each other, together with their partners, in membrane microdomains that provide a scaffold for the transmission of external stimuli to intracellular-signalling components.

Animals↗

Inhalation of stable dust extract prevents allergen induced airway inflammation and hyperresponsiveness.

BACKGROUND: Recent epidemiological studies have shown that growing up on a traditional farm provides protection from the development of allergic disorders such as hay fever and allergic asthma. We present experimental evidence that substances providing protection from the development of allergic diseases can be extracted from dust collected in stables of animal farms. METHODS: Stable dust was collected from 30 randomly selected farms located in rural regions of the Alps (Austria, Germany and Switzerland). The dust was homogenised with glass beads and extracted with physiological sodium chloride solution. This extract was used to modulate immune response in a well established mouse model of allergic asthma. RESULTS: Treatment of mice by inhalation of stable dust extract during sensitisation to ovalbumin inhibited the development of airway hyperresponsiveness and airway eosinophilia upon challenge, as well as the production of interleukin 5 by splenocytes and of antigen specific IgG(1) and IgE. Dust extract also suppressed the generation of human dendritic cells in vitro. The biological activity of the dust extract was not exclusively mediated by lipopolysaccharide. CONCLUSIONS: Stable dust from animal farms contains strong immune modulating substances. These substances can interfere with the development of both cellular and humoral immunity against allergens, thus suppressing allergen sensitisation, airway inflammation, and airway hyperresponsiveness in a murine model of allergic asthma.

Allergens↗

N-3 polyunsaturated fatty acids and allergic disease.

PURPOSE OF REVIEW: With escalating rates of allergic disease, it is vital to explore novel causal pathways. This review examines the evidence for a potential role of changing dietary intake of omega-3 polyunsaturated fatty acids in the development, treatment and prevention of allergic diseases. RECENT FINDINGS: Although it is difficult to determine the contribution of altered (decreased) dietary intake of omega-3 polyunsaturated fatty acids to the recent rise in the incidence of allergic disease, there is growing evidence that these nutrients have antiinflammatory properties and may modulate immune responses. These fatty acids have few side effects, and may be of some benefit in established allergic diseases (such as asthma and atopic dermatitis), although these effects are not strong. Because of this limited efficacy in established disease, the focus has shifted to the potential benefits of these immune modulators in earlier life for disease prevention. Two recent preliminary reports in infants suggest that dietary omega-3 polyunsaturated fatty acid supplements in pregnancy or in the early postnatal period could have immunomodulatory properties and associated clinical effects, although more studies are now needed. Novel synthetic polyunsaturated fatty acids with more potent and selective antiinflammatory effects may also provide safe therapeutic and preventive strategies in the future. SUMMARY: Dietary factors are important but still under-explored candidates in the search for environmental strategies to reduce the enormous impact of allergic diseases in modernized societies. There is an ongoing need for further research into the role of omega-3 polyunsaturated fatty acids in allergic disease, particularly in early life before atopy is established.

Adjuvants, Immunologic↗

Differential estrogen receptor gene expression in human peripheral blood mononuclear cell populations.

Estrogens have been shown to modulate immune responses. Several studies have demonstrated the capacity of T cells, B cells, and monocytes to respond to estrogens and estrogen receptor (ER) expression in these cell types has been reported. However, little is known regarding the relative expression in these cells of ERalpha and the more recently identified ERbeta. In the present study, results of quantitative TaqMan RT-PCR analyses indicate that ERs are differentially expressed in PBMC subsets. CD4+ T cells express relatively high levels of ERalpha mRNA compared with ERbeta, whereas B cells express high levels of ERbeta mRNA but low levels of ERalpha. Peripheral blood CD8+ T cells and monocytes express low but comparable levels of both ERs. This quantitative analysis of ER expression in distinct PBMC subsets may provide a basis for dissecting the mechanisms of immune modulation by estrogens and identifying therapeutic targets for the treatment of inflammatory and immunologic disorders.

Female↗

HLA expression and immunologic properties of differentiated and undifferentiated mesenchymal stem cells.

OBJECTIVE: Mesenchymal stem cells (MSC) do not elicit alloreactive lymphocyte responses due to immune modulations. We investigated the immunologic properties of MSC after differentiation along three lineages: bone, cartilage, and adipose. METHODS AND RESULTS: Flow cytometry showed that undifferentiated MSC express HLA class I but not class II, although HLA class II was present intracellularly as detected by Western blot. Addition of interferon gamma (IFN-gamma) for 48 hours induced greater than 90% of cells to express HLA class II. No lymphocyte response was induced by allogeneic irradiated MSC as stimulators. Results were similar using MSC pretreated with IFN-gamma. After growth of cells in medium to induce differentiation to bone, cartilage, or adipose for 6 or 12 days, the expression of HLA class I increased but no class II was detected on the cell surface. The ability to upregulate HLA class II on the cell surface after exposure to IFN-gamma for 48 hours was clearly diminished after the cells had been cultured in differentiation medium for 6 or 12 days, with only 10% of cells expressing HLA class II. Using MSC grown in osteogenic, chondrogenic, or adipogenic medium as stimulator cells, no lymphocyte alloreactivity was seen, even if differentiated MSC had been pretreated with IFN-gamma. MSC inhibit mixed lymphocyte cultures, particularly after osteogenic differentiation. This suppression was further enhanced by IFN-gamma. CONCLUSIONS: Undifferentiated and differentiated MSC do not elicit alloreactive lymphocyte proliferative responses and modulate immune responses. The findings support that MSC can be transplantable between HLA-incompatible individuals.

Adolescent↗

Adjuvant immunotherapy is dependent on inducible nitric oxide synthase.

Rodents immunized with complete Freund's adjuvant (CFA) are resistant to subsequent attempts to induce autoimmune disease, while animals immunized with incomplete Freund's adjuvant (IFA) remain susceptible. Mycobacterial extracts can stimulate inducible nitric oxide synthase (NOS2) gene transcription. Robust expression of NOS2 has been linked to suppression of T cell proliferation and alterations in immune responses. Our studies investigated the hypothesis that the immunoprotective effect of CFA before immunization requires functional NOS2. NOS2 gene expression is chronically elevated in lymph nodes and spleens of CFA-immunized mice. Maximal expression of NOS2 after CFA immunization requires the presence of functional type I tumor necrosis factor alpha receptor (TNFR1) and interferon gamma. Groups of nontreated and CFA-preimmunized male C57BL/6J or C57BL/6NOS2(-/)- mice were immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 in CFA to induce experimental allergic encephalomyelitis (EAE). Wild-type C57BL/6J mice were protected from the development of symptoms of EAE, while the NOS2(-/)- mice failed to be protected. NOS2-dependent effects of CFA included an augmentation of the MOG-specific IgG1 response, a decrease in interleukin 6 production by MOG-reactive lymphocytes, and a marked decrease in mononuclear cell infiltrates in the central nervous system. These studies support the hypothesis that CFA immunization modulates immune responses through a nitric oxide-dependent mechanism.

Amino Acid Sequence↗

Protection of mice from lethal influenza: evidence that defective interfering virus modulates the immune response and not virus multiplication.

Intranasal administration of defective interfering (DI) influenza virus (A/WSN) ensured the survival of 80% of C3H mice otherwise lethally infected with WSN by the intranasal route, whereas a control group which received beta-propiolactone-inactivated DI virus in place of DI virus died at 7.4 days post-infection. DI virus-treated mice developed significantly less lung consolidation than controls although qualitatively the cellular pathology in the two groups was indistinguishable. Surprisingly, in view of the accepted mode of action of DI virus interference, multiplication of infectious virus in the lung, production of viral haemagglutinin (HA) antigen and neuraminidase, and the distribution and amount of viral antigen in cells as shown by immune labelling were unaffected by the presence of active DI virus. Furthermore, assays of lung extracts showed that DI virus was not stimulating significantly greater amounts of interferon than the control inactivated DI virus. An alternative explanation arises from the fact that the pathology of influenza in inbred mice is immune (T lymphocyte)-mediated. Thus, since there is no evidence that DI virus affects virus multiplication we suggest that DI virus is responsible for ameliorating the damaging host responses. Another aspect of the immune response modulated by DI virus was the enhancement of local haemagglutination-inhibiting (HI) antibody in the lung, with peak increases of up to 10-fold over the relevant controls being demonstrated at 5 days after infection. This antibody was presumably complexed to HA antigen in the lung as activity was only demonstrated after elution at low pH. It had no detectable neutralizing activity (less than 10% HI: neutralization ratio of convalescent serum) which accounts for the coexistence of local antibody and virus infectivity. Mice infected with virus alone or which received beta-propiolactone-inactivated DI virus in addition to a lethal dose of WSN did not develop significant amounts of lung antibody. No differences were seen in serum HI titres. The increased level of antibody could not be attributed to the presence of greater amounts of HA antigen in lungs of mice treated with DI virus, as ELISA showed no significant difference from control preparations. The possibility that the two modulated immune responses are linked through HI antibody blocking access of T cells to cell membrane-borne HA antigen is discussed.

Animals↗

Dynamics of CD4+CD25+ T cells in spleens and mesenteric lymph nodes of mice infected with Schistosoma japonicum.

CD4+CD25+ T cells play a major role in modulating immune response, but few reports have been published about schistosomiasis. Here, we investigated the changes in CD4+CD25+ T cell populations in spleens and mesenteric lymph nodes of mice infected with Schistosoma japonicum. The proportions of CD4+CD25+ T cells in total CD4+ T cells were analyzed by flow cytometry. CD25 and Foxp3 expression was measured by real-time quantitative polymerase chain reaction. The suppressive activities of CD4+CD25+ T cells were detected by in vitro proliferation of splenocytes. Evidence showed that the percentage of CD4+CD25+ T cells was the same as controls 3 weeks post-infection. At the acute stage of infection, the percentage decreased significantly. However, at the chronic stage of infection, it rebounded to normal levels or even higher. The expression of the CD25 and Foxp3 showed gradual increase along with the infection progress. In vitro experiment also showed the strong suppressive effect of CD4+CD25+ T cells, isolated during the chronic stage, on proliferation of the CD25- splenocytes. This is the first time that the dynamics of CD4+CD25+ T cell populations was demonstrated in mice infected with schistosomiasis. In conclusion, our data indicated that CD4+CD25+ cells might be involved in the immune modulation during S. japonicum infection, which enhances current knowledge of the mechanisms of the immuno-downregulation and re-infection in schistosomiasis.

Animals↗

Acupuncture stimulation enhances splenic natural killer cell cytotoxicity in rats.

Acupuncture stimulation of the anterior tibial muscle, which is equivalent to Tsu-sanli point (S36) stimulation and which induces acupuncture analgesia, enhanced YAC-1 cell lytic activity of the splenic natural killer cells (NK activity) from pentobarbital anaesthetized Wistar rats. On the other hand, abdominal muscle stimulation, which does not induce acupuncture analgesia, did not affect NK activity. The serum from rats treated with acupuncture stimulation (acupuncture-stimulated rats) also enhanced the NK activity of other intact rats. The reinforcement effect of serum remained after heat inactivation (56 degrees C, 30 min). The serum from acupuncture-stimulated rats also had more potent complement activity than that from control rats. These results indicate the following considerations: 1) the Tsu-sanli point may be one of the specific points modulating immune activity, 2) this immune modulation system may share a common nervous pathway with the acupuncture analgesia-producing system, 3) acupuncture stimulation may modify NK activity through unknown heat stable humoral factors as well as the nervous system, and 4) acupuncture stimulation may activate the complement system.

Animals↗

[The influence of paternal lymphocytes immunization on percentage of peripheral blood CD16+/CD56+ cells in women with primary recurrent spontaneous abortion].

OBJECTIVES: Paternal lymphocytes immunization has been proposed for several years as an efficient treatment for unexplained Recurrent Spontaneous Abortion (RSA), however precise mechanism that underline the benefits of this immunotherapy is still unclear. DESIGN: The aim was to study the influence of paternal lymphocytes immunization on percentage of peripheral blood NK cells (CD16+/CD56+) in women with primary RSA of unknown etiology. MATERIALS AND METHODS: 48 patients with history of 3-5 (mean 3.3 +/- 0.7) consecutive primary RSA of unknown etiology were selected for the study. Immunotherapy with paternal lymphocytes, isolated from 100 ml of peripheral blood, was performed twice prior conception with a 4-week interval. The percentage of NK cells (CD16+/CD56+) was estimated using standard flow-cytometric immunofluorescent techniques for whole blood with one-step monoclonal anti-CD16/CD56 antibodies. Statistical analysis was performed with Wilcoxon test and the p value less than 0.05 was accepted as statistically significant. RESULTS: It was found that paternal lymphocytes immunization significantly decreases the percentage of NK cells in peripheral blood in women with RSA (23.9 +/- 8.5 vs. 16.2 +/- 7.0; p = 0.009). CONCLUSIONS: The data of the present studies suggest that paternal lymphocytes immunization modulate immunity in women with primary unexplained RSA significantly decreasing the percentage of NK cells (CD16+/CD56+) in peripheral blood.

Abortion, Habitual↗

[Transplantation of pancreas and islet cells in insulin dependent diabetes mellitus--status after 25 years].

The Danish study group for metabolic studies after transplantation of the pancreas. Development of combined pancreatic and renal transplantation and transplantation of islet cells in the treatment of insulin-dependent diabetes mellitus is reviewed. Transplantation of the pancreas is undertaken in Denmark on the indication of diabetes mellitus complicated by terminal diabetic nephropathy in patients who are considered, in advance, as candidates for renal transplantation. During recent years, improved results have been obtained by combined pancreatic renal transplantation with patient survival of up to 96% and graft survival of up to 84% after two years. Despite normal HbA1C, the intermediate metabolism is abnormal after combined pancreatic and renal transplantation. At present, it does not appear to prevent or arrest development of diabetic retinopathy while the results indicate that progression of diabetic nephropathy and neuropathy can be halted. Development in islet cell transplantation is promising. As yet, there has only been limited success with transplantation of foetal islet cells and this also involves great ethical problems. Xenographic transplantation of foetal islet cells may be of current value in the future. During recent years, 20% of islet cell transplantations from adult human donors have resulted in insulin independence for briefer periods (maximal 24 months, January 1992). Improved methods have been developed in immune modulation, immune isolation and cryopreservation and these make purification and harvesting of adequate quantities of islet cell mass possible to obtain exogenic insulin independence. Development of new immune suppressives has not improved the results. In the future, islet cell transplantation will possibly become part of the treatment of insulin-dependent diabetes mellitus.

Adolescent↗

Maternal modulation of neonatal immune system development.

Changes in programming of neonatal immune development were effected through maternal immune modulation (Leishmania major inoculation). In progeny of these dams, immune profiles in both blood and spleen were changed throughout the neonatal period and were pronounced after weaning. White blood cell (WBC) and lymphocyte counts in blood of 45-day-old progeny were two-fold less than control animals. In blood, proportions of B cells were greater, while T helpers, Tc/s and NK cells were less than in controls. In contrast, proportions of splenic B and NK cells were greater than controls. But, proportions of all T and Tc/s cells on d20 and 45 were lower than controls. In blood, absolute numbers of all T, Th naïve and Th memory cells were lower than in controls. In contrast, in the spleen, numbers of NK, T and Th naive and memory cells were up to 200% greater than in control pups. Cytokine responses of splenic lymphocytes stimulated through CD3 ligation revealed no difference in IL-4 production. In contrast, IL-2 and IFNgamma were lower on d45 and 5, respectively, in the experimental compared to control mice. These data support the hypothesis that maternal immune events during gestation can modulate the pattern of immune development in offspring.

Animals↗

Modulation of the immune response in fish.

This is a brief overview of the field of immune modulation in fish. Special attention is given to the effects of biological rhythms on the immune responses of animals. Biological rhythms in fish appear to be poorly studied and the effects of such rhythms on fish immune responses needs to be evaluated. Implications for research on the modulation of fish immune responses are discussed.

Animals↗