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Results for “immune modulation”

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PubMed1999

Modulation of immune function by a modified bovine whey protein concentrate.

The commercial preparation of dairy foodstuffs generates large volumes of by-products, many of which have as yet undocumented effects on mammalian immune function. In the present report, a modified whey protein concentrate (mWPC), derived as a by-product from the commercial manufacture of cheese, was tested for its ability to modulate murine immune function in vitro. The mWPC suppressed T and B lymphocyte proliferative responses to mitogens in a dose-dependent fashion. The mWPC also suppressed alloantigen-induced lymphocyte proliferation during a mixed leucocyte reaction, but showed no suppressive effect against IL-2-sustained proliferation of mitogen-activated T cell blasts. Other indices of lymphocyte activation, such as cytokine secretion and the formation of activated (CD25+) T cell blasts, were suppressed by the mWPC, suggesting that the mode of suppression may be to inhibit the lymphocyte activation process. Enzymatic digestion by pepsin and pancreatin, under physiologically realistic conditions in vitro, ablated the immunomodulatory function of the mWPC. These results are discussed in relation to the potential development of complex-mixture dairy products into health-modulating products.

Animals↗

PubMed2002

Pineal melatonin secretion, but not ocular melatonin secretion, is sufficient to maintain normal immune responses in Japanese quail (Coturnix coturnix japonica).

Reports that plasma melatonin is an important immune regulator in avian species have been rather sparse and contradictory. Also, the primary source of immune-modulating melatonin has yet to be determined in birds. In Japanese quail (Coturnix coturnix japonica), the pineal gland and eyes contribute roughly two thirds and one third of the melatonin found in the blood, respectively. Two experiments were conducted to evaluate melatonin as an immune modulator in Japanese quail and to determine the primary source of immune-modulating melatonin in this species. Experiment 1 was designed to evaluate the involvement of the pineal gland and the eyes in immunocompetence. Each of three groups of quail was assigned a surgical treatment and the cellular and humoral immune responses were determined 8 weeks following surgery. The surgical treatments were pinealectomy (Px), sham pinealectomy (SH-Px), and ocular enucleation (eye removal (Ex)). Experiment 2 utilized exogenous melatonin as a replacement to reconstitute immune responses in surgically immunocompromised birds. In this experiment, 50.0 microg/ml of melatonin, or diluent only, was provided to Px and SH-Px birds in the drinking water ad libitum. The cellular and humoral immune responses were determined after 8 weeks of melatonin treatment. In both experiments, a cutaneous basophil hypersensitivity reaction to phytohemagglutinin was measured to evaluate the cellular immune response. To evaluate the humoral immune response, primary antibody titers were determined 7 days postintravenous injection with a Chukar red blood cell suspension. Flow cytometric analysis of peripheral blood lymphocytes was performed to determine the relative percentage of CD4(+) and CD8(+) T- and B-lymphocytes in all treatments of Experiment 2. In Experiment 1, both the SH-Px and Ex surgical treatments produced similar cellular and humoral immune responses, and these responses were significantly greater than those in Px-treated birds. Pinealectomy significantly reduced the cellular and humoral immune responses from SH-Px by 25.8% and 41.3%, respectively. In Experiment 2, Px again resulted in depressed cellular and humoral immune responses. In addition, Px significantly reduced CD8(+) T-lymphocyte numbers compared to SH-Px, while B-lymphocytes remained unchanged. Melatonin administration to Px birds increased the cellular (32.9%) and humoral (30.6%) immune responses to the level of control (SH-Px) birds, although this reconstitution was not due to increased CD8(+) T- or B-lymphocytes. From these data, it was clear that removal of the pineal gland, but not the eyes, reduced cellular and humoral immune responses, which were reconstituted to normal levels by exogenous melatonin. These data suggest that immunodepression is only observed in birds with two thirds of the plasma melatonin removed by pinealectomy. Removal of one third of the plasma melatonin (by ocular enucleation) is not sufficient to reduce cellular and humoral responses in the Japanese quail.

Animals↗

PubMed1987

The effect of lactoferrin on complement mediated modulation of immune complex size.

Earlier we showed that human lactoferrin is capable of inhibiting the complement-mediated lysis of antibody-coated erythrocytes due to an inhibition of the formation of the classical C3 convertase. In this report the effect of lactoferrin on complement mediated modulation of immune complex size was studied. Lactoferrin was shown to inhibit the complement-dependent solubilization of immune precipitates with kinetics resembling that seen by others using C2 deficient serum. Lactoferrin, however, did not affect the complement-dependent inhibition of immune precipitation. These findings confirm our earlier observations that lactoferrin has no effect on the activation of the very early complement components (C1 and C4), but inhibits C3 deposition on immune complexes which is a crucial mechanism in immune precipitate solubilization.

Animals↗

PubMed2003

Potent, persistent induction and modulation of cellular immune responses in rhesus macaques primed with Ad5hr-simian immunodeficiency virus (SIV) env/rev, gag, and/or nef vaccines and boosted with SIV gp120.

Immunity elicited by multicomponent vaccines delivered by replication-competent Ad5hr-simian immunodeficiency virus (SIV) recombinants was systematically investigated. Rhesus macaques were immunized mucosally at weeks 0 and 12 with Ad5hr-SIV(smH4) env/rev, with or without Ad5hr-SIV(mac239) gag or Ad5hr-SIV(mac239) nef, or with all three recombinants. The total Ad5hr dosage was comparably adjusted among all animals with empty Ad5hr-DeltaE3 vector. The macaques were boosted with SIV gp120 in monophosphoryl A-stable emulsion adjuvant at 24 and 36 weeks. Controls received Ad5hr-DeltaE3 vector or adjuvant only. By ELISPOT analysis, all four SIV gene products elicited potent cellular immune responses that persisted 42 weeks post-initial immunization. Unexpectedly, modulation of this cellular immune response was observed among macaques receiving one, two, or three Ad5hr-SIV recombinants. Env responses were significantly enhanced throughout the immunization period in macaques immunized with Ad5hr-SIV env/rev plus Ad5hr-SIV gag and tended to be higher in macaques that also received Ad5hr-SIV nef. Macaques primed with all three recombinants displayed significant down-modulation in numbers of gamma interferon (IFN-gamma)-secreting cells specific for SIV Nef, and the Env- and Gag-specific responses were also diminished. Modulation of antibody responses was not observed. Down-modulation was seen only during the period of Ad5hr-recombinant priming, not during subunit boosting, although SIV-specific IFN-gamma-secreting cells persisted. The effect was not attributable to Ad5hr replication differences among immunization groups. Vaccine delivery via replication-competent live vectors, which can persistently infect new cells and continuously present low-level antigen, may be advantageous in overcoming competition among complex immunogens for immune recognition. Effects of current multicomponent vaccines on individual immune responses should be evaluated with regard to future vaccine design.

Adenoviridae↗

PubMed1998

Immune induction and modulation by topical ocular administration of plasmid DNA encoding antigens and cytokines.

In this article, the authors investigated if administration of eukaryotic expression plasmid DNA delivered to the ocular surface provided a means of inducing and modulating the immune response to herpes simplex virus (HSV). Topical application of gB DNA led to the development of HSV specific systemic humoral and cellular immunity. In addition, mucosal antibody was induced at both proximal and distal locations. Topically gB DNA immunized animals were protected against lethal challenge via either the systemic or the vaginal mucosal routes. Ocular pre-exposure to DNA encoding the cytokines interleukin (IL)-4 or IL-10, but not IL-2 or interferon-gamma, modulated the severity of the immunoinflammatory response to subsequent corneal infection with HSV. The present results indicate that the ocular surface provides a readily accessible site for DNA immunization and is suitable for both immune induction and modulation of the nature of the immune response that is induced.

Adjuvants, Immunologic↗

PubMed2005

Autoimmune Myasthenia Gravis: Recommendations for Treatment and Immunologic Modulation.

Treatment for myasthenia gravis should be individualized to each patient based on the clinical characteristics of myasthenia including the distribution, duration, and severity of weakness and resulting functional impairment; the risks for treatment complications related to age, gender, and medical comorbidities; and the presence of thymoma. Acetylcholinesterase inhibitors provide temporary, symptomatic treatment for all forms of myasthenia gravis. Immune modulators address the underlying autoimmune process in myasthenia gravis, but are associated with potential complications and side effects. Most patients with generalized myasthenia who have significant weakness beyond the ocular muscles and who remain symptomatic, despite treatment with cholinesterase inhibitors, are candidates for immune modulation. Although corticosteroids are effective for long-term immune modulation in myasthenia gravis, several more contemporary immunomodulators including azathioprine, cyclosporine, and mycophenolate mofetil have shown efficacy in myasthenia gravis and are used increasingly as first-line treatments and as steroid-sparing agents. Plasma exchange is used to achieve rapid improvement in patients with myasthenic crisis or exacerbation, to improve strength before a surgical procedure or thymectomy, and to minimize steroid-induced exacerbation in patients with oropharyngeal or respiratory muscle weakness. Intravenous immunoglobulin represents an alternative to plasma exchange in patients requiring relatively rapid short-term improvement in the setting of poor venous access. Because of a lack of controlled trials, the role of thymectomy in nonthymomatous myasthenia gravis is unclear, although evidence suggests that thymectomy increases the probability for myasthenic remission or improvement.

Journal Article↗

PubMed2006

Human plasmacytoid dendritic cell function: inhibition of IFN-alpha secretion and modulation of immune phenotype by vasoactive intestinal peptide.

Plasmacytoid dendritic cells (PDC) are considered the main sentinels against viral infections and play a major role in immune tolerance. Vasoactive intestinal peptide (VIP) is a potent immunomodulator, whose role in PDC function is unknown. The present study was designed to investigate whether human PDC express VIP receptors and whether VIP has immunological effects on PDC. Using real-time RT-PCR and immunofluorescence, we demonstrated that VIP receptors VPAC1 and VPAC2 are expressed on PDC. After culturing PDC with VIP and CpG oligodeoxynucleotides for 48 h, expression of surface molecules with significance for PDC-T cell interactions as well as IFN-alpha secretion were quantified using FACS analysis and ELISA, respectively. For functional assays, CFSE-stained CD4+ T cells were coincubated with differentially treated PDC. T cell proliferation and production of various cytokines were determined by FACS analysis and ELISA. VIP enhanced PDC expression of CD86, MHC II, and CCR7. In contrast, VIP inhibited PDC secretion of IFN-alpha and expression of Neuropilin-1 and MHC I. The potential of CpG oligodeoxynucleotide-activated PDC to induce proliferation of allogeneic CD4(+) T cells was impaired when VIP was present during activation. Furthermore, pretreatment of PDC with VIP resulted in a decrease of the IFN-gamma:IL-4 ratio in cocultured T cells, suggesting a modulation of the immune response toward Th2. Taken together, these results strongly suggest that VIP regulates the immunological function of human PDC. VIP may thus be involved in the modulation of immune responses to viral infections as well as in the maintenance of immune tolerance.

CD4-Positive T-Lymphocytes↗

PubMed1995

Selective modulation of immune function resulting from in vitro exposure to methylenedioxymethamphetamine (Ecstasy).

Abuse of illicit analogs of methamphetamine (i.e., 'designer drugs') represents a growing problem. One of the most popular methamphetamine analogs is (+/-)-3,4-methylenedioxymethamphetamine (MDMA), commonly known as Ecstasy. The authors demonstrated previously that in vitro exposure to methamphetamine results in modulation of immune functional parameters necessary for host defense. The current study was performed to assess the potential direct (in vitro) immunomodulatory effect of exposure to a modified methamphetamine. Splenocytes or peritoneal macrophages from B6C3F1 mice were cultured in vitro at MDMA concentrations of 0.0001-100 microM. T-cell regulatory function was assessed by anti-CD3-mediated production of IL-2 and IL-4, B-cell function was assessed by quantitating cellular proliferation, natural immunity was assessed by quantitating natural killer (NK) cell activity, T-cell effector function was evaluated as a function of cytotoxic T-lymphocyte (CTL) activity, and macrophage function was assessed by IL-6 tumor necrosis factor (TNF) production. In vitro exposure to MDMA had no effect on B-cell proliferation at any concentration tested. In comparison, in the absence of direct cellular toxicity, production of IL-2 was enhanced at concentrations as low as 0.0001 microM. IL-4 production was not affected by exposure to any concentration of MDMA examined, suggesting a differential alteration in T-helper cell function by this compound. Basal and augmented NK cell function were enhanced at MDMA concentrations between 0.0001 and 1.0 microM when examined at an effector:target ratio of 100:1. CTL induction was significantly suppressed at a concentration of 100 microM. Finally, macrophage production of TNF was slightly suppressed at 10 and 100 microM MDMA, although this inhibition was not statistically significant.

Adjuvants, Immunologic↗

PubMed2002

Immune response to poxvirus infections in various animals.

The study of infections of vertebrate animals by poxviruses has remained a dynamic area of research for the last century. The host range of poxviruses vary from extremely narrow to exceedingly broad, and they have been shown to enter their host by either the respiratory route or through the skin. The severity of infection varies dramatically from one species to another, causing anywhere from a local, self-limiting infection, to a devastating systemic disease, such as smallpox. Although the immune response to poxvirus infections are very similar to that seen in other viral infections, the poxviruses, unlike most other viruses (with the exception of Herpes viruses), are able to defend themselves. They have been shown to carry a repertoire of proteins involved in immune evasion and immune modulation. Poxviruses encode proteins involved in blocking many of the strategies employed by the host to combat viral infections; they encode for proteins that block activity of many chemokines, cytokines, serine proteases, and even complement. Traditionally, different animal models have been used to study the pathogenesis of poxvirus infections, and the characterization of virulence genes using mutant poxviruses. Additionally, new animal models are being developed to study the possible therapeutic uses many of these poxvirus immune modulating proteins might have. This review discusses the host immune response against poxvirus infections in various animals, the viral counter response to the host, and the animal models used to study poxvirus infection and immune modulating proteins.

Animals↗

PubMed2004

Azithromycin modulates murine immune responses to pneumococcal conjugate vaccine and inhibits nasal clearance of bacteria.

Macrolide antibiotics, including azithromycin, have been implicated in the modulation of host immune responses, independently of their antimicrobial properties. The present work was designed to study the effect that azithromycin has on protective humoral immune responses induced by a 7-valent, polysaccharide, pneumococcal conjugate vaccine (PCV7). By use of a murine vaccination/challenge model, it was found that inoculation with azithromycin led to significantly lower primary antibody responses, decreased recall proliferative responses, and, in nasal cavities, impaired clearance of Streptococcus pneumoniae serotype 14 from the nasal cavities. The results demonstrate that azithromycin can be inhibitory with regard to protective immune responsiveness.

Animals↗

PubMed2001

Cyclophosphamide, doxorubicin, and paclitaxel enhance the antitumor immune response of granulocyte/macrophage-colony stimulating factor-secreting whole-cell vaccines in HER-2/neu tolerized mice.

Tumor-specific immune tolerance limits the effectiveness of cancer vaccines. In addition, tumor vaccines alone have a limited potential for the treatment of measurable tumor burdens. This highlights the importance of identifying more potent cancer vaccine strategies for clinical testing. We tested immune-modulating doses of chemotherapy in combination with a granulocyte/macrophage-colony stimulating factor (GM-CSF)-secreting, HER-2/neu (neu)-expressing whole-cell vaccine as a means to treat existing mammary tumors in antigen-specific tolerized neu transgenic mice. Earlier studies have shown that neu transgenic mice exhibit immune tolerance to the neu-expressing tumors similar to what is observed in patients with cancer. We found that cyclophosphamide, paclitaxel, and doxorubicin, when given in a defined sequence with a GM-CSF-secreting, neu-expressing whole-cell vaccine, enhanced the vaccine's potential to delay tumor growth in neu transgenic mice. In addition, we showed that these drugs mediate their effects by enhancing the efficacy of the vaccine rather than via a direct cytolytic effect on cancer cells. Furthermore, paclitaxel and cyclophosphamide appear to amplify the T helper 1 neu-specific T-cell response. These findings suggest that the combined treatment with immune-modulating doses of chemotherapy and the GM-CSF-secreting neu vaccine can overcome immune tolerance and induce an antigen-specific antitumor immune response. These data provide the immunological rationale for testing immune-modulating doses of chemotherapy in combination with tumor vaccines in patients with cancer.

3T3 Cells↗

PubMed2006

Influence of garlic, synthetic 1,2,4-triasole derivative and herbal preparation echinovit C on selected indices of turkey-hens non-specific immunity.

Successful results of earlier studies on testing the immune-modulating and anti-microbial properties of 1,2,4-triasole derivative as well as benefitial application of natural bio-stimulators in animal's prophylaxis and treatment inspired us to undertake further investigations. The aim of the present study was to evaluate and compare the prophylaxis effects of two natural immune-modulating agents, garlic (Allium sativum) extract and Echinovit C preparation and synthetic derivative of 1,2,4-triasole on non-specific immunity indices in slaughter turkey-hens. The results obtained suggest that the strongest stimulatory effect is exerted by garlic followed by 1,2,4-triasole derivative and Echinacea juice. Immune-modulating action of the substances applied was manifested by an increase in cellular immune parameters: the percentage of phagocyting cells, NBT-positive granulocytes and lysozyme level.

Animals↗

PubMed2006

PACAP 38 as a modulator of immune and endocrine responses during LPS-induced acute inflammation in rats.

The effect of PACAP 38 administration on neuroendocrine and immune parameters was examined in rats with LPS-induced peritonitis. Treatment with PACAP 38 alone did not influence the serum level of the cytokines and hormones examined, but significantly decreased immune cell activity. When administered together with LPS, PACAP 38 reversed its effect on immune and humoral parameters, causing a decrease in the serum concentrations of TNFalpha and corticosterone, and an increase in T4 and GH. The majority of PACAP 38 effects disappeared earlier than those previously observed for VIP. PACAP 38 appears to represent a short-lasting modulator of immune and endocrine responses during acute inflammation.

Acute Disease↗

PubMed2005

Does the addition of glutamine to enteral feeds affect patient mortality?

OBJECTIVE: Studies have failed to consistently demonstrate improved survival in intensive care unit (ICU) patients receiving immune-modulating nutrient-enhanced enteral feeds when compared with standard enteral feeds. The objective was to study in a prospective fashion the effects of adding glutamine to standard or immune-modulated (supplemented with omega-3 fatty acids, beta-carotene, and amino acids such as glutamine and arginine) tube feeds. DESIGN: Prospective, unblinded study using sequential allocation. SETTING: A university surgical trauma ICU. PATIENTS: All surgical and trauma patients admitted to the surgical trauma ICU at a university hospital over a 3-yr period who were to receive enteral feeds (n = 185). INTERVENTIONS: Sequential assignment to three isocaloric, isonitrogenous diets was performed as follows: standard 1-kcal/mL feeds with added protein (group 1), standard feeds with the addition of 20-40 g/day (0.6 g/kg/day) glutamine (group 2), or an immune-modulated formula with similar addition of glutamine (group 3). The goal for all patients was 25-30 kcal/kg/day and 2 g/kg/day protein. MEASUREMENTS AND MAIN RESULTS: Patients were followed until discharge from the hospital. The primary end point was in-hospital mortality, and multiple secondary end points were recorded. In-hospital mortality for group 1 was 6.3% (four of 64) vs. 16.9% (ten of 59, p = .09) for group 2 and 16.1% (ten of 62, p = .09) for group 3. After controlling for age and severity of illness, the difference in mortality between patients receiving standard tube feeds and all patients receiving glutamine was not significant (p < or = .11). There were no statistically significant differences between the groups for secondary end points. CONCLUSIONS: The addition of glutamine to standard enteral feeds or to an immunomodulatory formula did not improve outcomes. These findings suggest that enteral glutamine should not be routinely administered to patients with surgical critical illness.

APACHE↗

PubMed2002

Androgens and estrogens modulate the immune and inflammatory responses in rheumatoid arthritis.

Generally, androgens exert suppressive effects on both humoral and cellular immune responses and seem to represent natural anti-inflammatory hormones; in contrast, estrogens exert immunoenhancing activities, at least on humoral immune response. Low levels of gonadal androgens (testosterone/dihydrotestosterone) and adrenal androgens (dehydroepiandrosterone and its sulfate), as well as lower androgen/estrogen ratios, have been detected in body fluids (that is, blood, synovial fluid, smears, salivary) of both male and female rheumatoid arthritis patients, supporting the possibility of a pathogenic role for the decreased levels of the immune-suppressive androgens. Several physiological, pathological, and therapeutic conditions may change the sex hormone milieu and/or peripheral conversion, including the menstrual cycle, pregnancy, the postpartum period, menopause, chronic stress, and inflammatory cytokines, as well as use of corticosteroids, oral contraceptives, and steroid hormonal replacements, inducing altered androgen/estrogen ratios and related effects. Therefore, sex hormone balance is still a crucial factor in the regulation of immune and inflammatory responses, and the therapeutical modulation of this balance should represent part of advanced biological treatments for rheumatoid arthritis and other autoimmune rheumatic diseases.

Androgens↗

PubMed2004

Role of the D prostanoid receptor 1 in the modulation of immune and inflammatory responses.

Prostaglandins (PGs) are potent eicosanoid lipid mediators derived from phospholipase-released arachidonic acid, which are involved in numerous homeostatic biological functions and inflammation. They are generated by the sequential action of cyclooxygenase isozymes and cell-specific PG synthases. Along with their role in inflammatory responses, recent accumulating evidence strongly suggests that PGs, including PGD2, are part of a complex regulatory network that modulates the immune system. PGD2 is the major prostanoid secreted by activated mast cells and has long been implicated in allergic diseases. The aim of this review is to discuss our current understanding of the mode of action of PGD2 during Th2-mediated inflammation. We also discuss recent findings, which suggest that PGD2 exerts important effects on both immune and inflammatory responses by targeting the D prostanoid receptor 1 on dendritic cells, the most potent antigen-presenting cells.

Animals↗

PubMed1999

[Opioids and the immune system].

The immune response is partly regulated by the nervous system, that involves endogenous opioids, stimulating or depressing immune responses. Opioids modulate immune response by indirect and direct mechanisms. Indirect modulation occurs when the activation of opioid receptors within the nervous system modifies the activity of neuroendocrine axes or neurotransmission pathways. Direct modulation results from the effects of opioids on immune system cells. This requires the expression of membrane opioid receptors in these cells. Immunomodulating effects of morphine would be a result of the integration of indirect and direct effects. In animal models, morphine transiently depresses cellular and humoral immunity. In humans, morphine has similar effects; however, the real impact of morphine administration on the immune response in clinical situations in not yet known.

B-Lymphocytes↗

PubMed2026

How the microbiome shapes epigenetic trained memory in neuroinflammation: Implications for neurodegenerative diseases.

Neurodegenerative diseases are increasingly recognized as disorders involving immune dysregulation. However, the mechanisms underlying this dysfunction remain poorly characterized. Trained immunity has recently emerged as a potential contributor to immune dysregulation, particularly in neuroinflammation and neurodegenerative diseases, where trained immunity is the epigenetic reprogramming of innate immune responses following an initial inflammatory stimulus, which increases responses to subsequent exposures. In parallel, although the brain has traditionally been viewed as an immune-privileged organ, growing evidence indicates that peripheral immune activity exerts significant influence on neuroinflammation in the brain. A major driver of peripheral immunity is the microbiome. Therefore, this perspective aims to present a conceptual framework for a relationship between the microbiome, trained immunity, and neurodegenerative diseases. We first summarize evidence of trained immunity in the brain and its role in neurodegeneration. Next, we highlight the role of the microbiome in peripheral immune modulation and in trained immunity. Finally, we propose potential mechanisms through which the microbiome may induce or modulate trained immunity in the brain. These include: 1) immunogenic microbial metabolites that cross the blood-brain barrier and alter host cell epigenetics; 2) migration of peripherally trained myeloid cells into the brain; 3) viral infection-induced trained immunity that may predispose to neurodegeneration. Together, this perspective suggests that microbiome-induced trained immunity offers a novel mechanism linking peripheral immune regulation with neuroinflammation and neurodegeneration with implications for therapeutic targeting of epigenetic modification as a molecular prevention strategy for progression of neurodegeneration.

Humans↗