Direct Immunomodulation Research Articles

Immunological feedback loops generate parasite persistence thresholds that explain variation in infection duration.

Infection duration affects individual host fitness and between-host transmission. Whether an infection is cleared or becomes chronic depends on the complex interaction between host immune responses and parasite growth. Empirical and theoretical studies have suggested that there are critical thresholds of parasite dose that can determine clearance versus chronicity, driven by the ability of the parasite to manipulate host immunity. However, the mammalian immune response is characterized by strong positive and negative feedback loops that could generate duration thresholds even in the absence of direct immunomodulation. Here, we derive and analyse a simple model for the interaction between T-cell subpopulations and parasite growth. We show that whether an infection is cleared or not is very sensitive to the initial immune state, parasite dose and strength of immunological feedbacks. In particular, chronic infections are possible even when parasites provoke a strong and effective immune response and lack any ability to immunomodulate. Our findings indicate that the initial immune state, which often goes unmeasured in empirical studies, is a critical determinant of infection duration. This work also has implications for epidemiological models, as it implies that infection duration will be highly variable among individuals, and dependent on each individual's infection history.

Immunomodulation by ketamine as an adjunct to total intravenous anesthesia in patients undergoing minimally invasive radical prostatectomy: A randomized pilot trial.

Post-surgery immunomodulation, including reduced natural killer cell cytotoxicity (NKCC), is recognized as a predictor of poor outcomes in patients following cancer surgery. The present study investigated direct immunomodulation via ketamine as an anesthetic adjuvant in patients undergoing cancer surgery. The present non-double blinded randomized trial was conducted at Hirosaki University Hospital with 60 patients who underwent minimally invasive robotic radical prostatectomy to minimize the immunomodulation due to surgical stress. Patients received total intravenous anesthesia using propofol and remifentanil, with ketamine as an anesthetic adjuvant (the ketamine group) or without ketamine (the control group). The primary outcome was the difference in NKCC between these groups. The secondary outcomes were the differences in neutrophil-lymphocyte ratio (NLR) and levels of interleukin (IL)-6, IL-1β, IL-10 and tumor necrosis factor-alpha (TNF-α). NKCC and cytokines were measured before anesthesia (baseline) and at 6 and 24 h after baseline measurements were recorded. NLR was determined on the last day before admission and at 48 h post-baseline. NKCC values were similar in each group at 6 h when compared with respective baseline results (baseline control, 36.9±15.6%; 6 h control, 38.3±13.4%; baseline ketamine, 36.1±17.0%; 6 h ketamine, 36.6±16.4%) but significantly decreased at 24 h (control, 26.5±12.2%; ketamine, 24.1±12.7%; P<0.001). There were no significant differences in NKCC between the ketamine and control groups (P=0.64) at any of the assessed time points. NLR, IL-1β, IL-10 and TNF-α levels were also similar between two groups. In contrast, IL-6 at 24 h was significantly lower in the ketamine group compared with the control group (mean difference, -7.3 pg ml-1; 95% confidence interval, -14.4 to -0.2; P=0.04). Ketamine as an anesthetic adjuvant did not provide direct immunomodulation in patients who underwent cancer surgery.

Characterization of Inulin-Type Fructan from Platycodon grandiflorus and Study on Its Prebiotic and Immunomodulating Activity.

Platycodon grandiflorus is a plant widely used in traditional Chinese medicine, of which polysaccharides are reported to be the main components responsible for its bio-functions. In this work, the inulin-type fructan (PGF) was obtained by DEAE anion exchange chromatography from the water extracted from P. grandifloras. Characterization was performed with methanolysis, methylation, and NMR and the results showed that PGF is a β-(2-1) linked fructan, with terminal glucose and with a degree of polymerization of 2–10. In order to study its biofunctions, the prebiotic and immunomodulation properties were assayed. We found that PGF exhibited good prebiotic activity, as shown by a promotion on six strains of lactobacillus proliferation. Additionally, the PGF also displayed direct immunomodulation on intestinal epithelial cells and stimulated the expressions of anti-inflammatory factors. These results indicated that the inulin from P. grandiflorus is a potential natural source of prebiotics as well as a potential intestinal immunomodulator, which will be valuable for further studies and new applications.

Ceftriaxone and clavulanic acid induce antiallodynia and anti-inflammatory effects in rats using the carrageenan model.

IntroductionCeftriaxone (CFX) and clavulanic acid (CA) are 2 β-lactam molecules widely used as antibiotics. However, several reports of their antiallodynic properties have been published in recent years. Although this effect has been considered mostly due to a GLT1 overexpression, these molecules have also been proven to induce direct immunomodulation. In this work, we determine the acute analgesic effect of CFX and CA in an inflammatory pain model and assess if their administration may induce anti-inflammatory effects.MethodsThe carrageenan (Carr) test was used as an inflammatory pain model. Both mechanical and thermal responses were analyzed after CFX and CA administration at different times. A plethysmometer was used to determine inflammation. Also, TNF-α and IL-10 serum concentrations were determined by enzyme-linked immunosorbent assay.ResultsBoth CFX and CA induced a significant thermal antiallodynic effect 3 and 24 h after administration. Furthermore, CA induced a mechanical antiallodynic effect 30, 60, and 90 min after administration. Moreover, a significant anti-inflammatory effect was found for both molecules 24 h after Carr injection. Also, both CA and CFX modulated TNF-α and IL-10 serum concentrations at different times.ConclusionOur results provide evidence that both CFX and CA cause an analgesic effect on a Carr inflammatory pain model and that said analgesic effect differs between each β-lactam molecule. Furthermore, this effect may be related to an anti-inflammatory effect of both molecules and a direct TNF-α and IL-10 serum concentration modulation.

Terminal Sugar Moiety Determines Immunomodulatory Properties of Poly(propyleneimine) Glycodendrimers.

Poly(propyleneimine) dendrimers fully surface-modified with disaccharide moieties (maltose, cellobiose, and lactose) designed to mimic natural lectin receptor ligands were tested for their bioactivity in two myeloid cell lines: THP-1 and HL-60. Depending on the sugar modification, we observed variable activation of NF-κB, AP-1, and NF-AT signaling pathways: lactose-coated dendrimers had the strongest impact on marker gene expression and most signaling events with the notable exception of NF-κB activation in THP-1 cells. The two cell lines showed an overall similar pattern of transcription factor and gene expression activation upon treatment with glycodendrimers, suggesting the involvement of galectin and C-type lectin receptor types. An important result of this action was the overexpression of CD40 and IL8 genes, potentially leading to an activated, proinflammatory phenotype in the monocyte/macrophage cell lineage. These pharmacodynamic characteristics of glycodendrimers need to be taken into account during their pharmaceutical applications both in drug delivery and direct immunomodulation.

Exendin-4 Exhibits Enhanced Anti-tumor Effects in Diabetic Mice

Type 2 diabetes (T2D) is associated with increased risk of cancers. In this connection, we previously demonstrated the promoting effect of diabetes on HPV-associated carcinogenesis using a xenograft model in db/db diabetic mice. The underlying mechanism of this observation might be partly contributed by dysregulated immune response in diabetes. In this study, we hypothesized that the impaired anti-tumor immune response in diabetic status could be modulated by exendin-4, a glucagon-like protein receptor agonist which exhibits anti-diabetic effects. We inoculated 10-week old db/db mice with 2 × 107 CUP-1 cells (Human Papilloma Virus (HPV)-16 E7 transfected continuous cell line) subcutaneously underneath the scruff, and treated mice with high (30 nmol/kg) or low (10 nmol/kg) dose of exendin-4 for 13 days. Compared with control groups, exendin-4 suppressed subcutaneous tumor growth in a dose-dependent manner, accompanied by increased interferon (IFN)-γ secreting CD8+ cytotoxic T lymphocyte (CTL)/Foxp3+ regulatory T cell (Treg) ratio as well as Th1 proinflammatory cytokines IFN-γ and IL-2. Collectively, these findings suggested an anti-tumor effect of exendin-4 in diabetic conditions, which might be resulted from direct immunomodulation.

Alpha1-antitrypsin, an endogenous immunoregulatory molecule: distinction between local and systemic effects on tumor immunology

The acute-phase protein α1-antirypsin (AAT) has recently been suggested to exert beneficial effects in various immune-associated pathologies, such as graftversus-host disease, rheumatoid arthritis, multiple sclerosis and allogeneic transplantation. These effects have been demonstrated to take place through direct immunomodulation of dendritic cells, macrophages, neutrophils and B cells, while allowing, in a yet inexplicable distinction, intact isolated functions of T cells and NK cells. With such a unique discriminatory targeting of immunocytes, AAT drives immune responses simultaneously towards regulation of inflammation and expansion of antigen-specific regulatory T cells (Tregs). Based on this intriguing activity profile, a concern was raised regarding the impact of chronic treatment with human AAT with respect to susceptibility to tumors and to metastatic spread. Tumor development is linked to inflammatory responses in a manner which largely promotes immune evasion. Local innate immunocytes, such as tumor-associated macrophages (TAMs), tumor-associated dendritic cells (TADCs) and the recently appreciated tumor-associated neutrophils (TANs), are considered instrumental in primary tumor survival. This is accomplished in part by the release of growth factors and cytokines, including VEGF, TGFβ, IL-10 and IL-1 receptor antagonist (IL-1Ra), all of which have been demonstrated to be elevated in inflammatory conditions during AAT therapy. While clinical studies report heightened serum AAT levels in patients with a variety of advanced tumors, there is no evidence to point to a particular pro-tumor effect of AAT, and the possibility that its elevation in the blood might represent a meresystemic marker– rather than an accessory to tumor development– is grossly overlooked. Indeed, preclinical studies reveal significant inhibition of tumor development during treatment with AAT, and prolonged follow-up studies of individuals who receive life-long excessive doses of intravenous AAT do not depict a rise in tumor occurrence. Considering the prospect of AAT being indicated for medical indications to individuals with normal levels of the protein, its relation to tumor immunology is of immense importance. We hereby review the current knowledge regarding some possible roles that AAT may play, both locally and systemically, in the delicate and detrimental arena of tumor immunology.

Preliminary evidence of transcriptional immunomodulation by praziquantel in bluefin tuna and Atlantic salmon in vitro cultures

Praziquantel (PZQ), long-used in veterinary and human medicine for the treatment of helminth parasites, is known to enhance humoral and cellular immune responsiveness in mammals but has unknown direct immunomodulatory capabilities in fish. In the present study, we examined the ability of PZQ to induce gene transcriptional changes in immune-competent primary tissue/organ cultures of two highly important yet evolutionarily discrete fish species – Southern bluefin tuna Thunnus maccoyii and Atlantic salmon Salmo salar. These cultures consisted of mixed blood cell population for both species, as well as intestinal explants from bluefin. Although expression profiles varied between species and tissue/organ type, PZQ induced both T-cell receptor (more than twofold) and IL-8 transcriptional expression (more than fourfold). Additionally, increased expression of other inflammatory cytokines including IL-1β was detected in blood cell cultures from both species, and a general pattern of heightened antiviral signaling was observed. Specifically, elevated transcription of Type I (IFNα) and Type II (IFNγ) interferon in Atlantic salmon blood cultures along with elevated expression of MHC class I in blood cultures of both species. These findings provide preliminary evidence for direct immunomodulation by PZQ in fish and insight into its potential capacity as an immune stimulant/adjuvant in the rapidly expanding aquaculture industry.

New Strategies in the Treatment of Sepsis

Despite there being several important forms of treatment involving the early goal directed therapy and bundle implementations, a search for new options in the treatment of sepsis have been made inevitable by today’s persisting very high mortality rates. Some of these, such as antioxidant therapies and stem cell and gene therapies, are still in the experimental stages, while others, such as high-volume hemofiltration, use of high cut-off membranes, non-selective adsorption like coupled plasma filtration adsorption, selective adsorption of endotoxin with polymyxin-B column, are approaches supported by randomized, controlled studies [1,2]. Extracorporeal therapies used to be employed for renal replacement therapy, but can now be used for multiple organ support [2]. Additionally, they can also produce a direct immunomodulation effect by altering the level of inflammatory mediators in the blood, such as cytokines and chemokines, and performing modifications in the complements and coagulation systems [2]. In addition, inhale nitric oxide and immunoglobulin can be used as adjuvant therapies in these patients [3]. Used together with main forms of treatment of sepsis, such as antibiotics, these characteristics make it possible for successful outcomes to be achieved.

Minicircle DNA-based Gene Therapy Coupled With Immune Modulation Permits Long-term Expression of α-L-Iduronidase in Mice With Mucopolysaccharidosis Type I

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disease characterized by mutations to the α-L-iduronidase (IDUA) gene resulting in inactivation of the IDUA enzyme. The loss of IDUA protein results in the progressive accumulation of glycosaminoglycans within the lysosomes resulting in severe, multi-organ system pathology. Gene replacement strategies have relied on the use of viral or nonviral gene delivery systems. Drawbacks to these include laborious production procedures, poor efficacy due to plasmid-borne gene silencing, and the risk of insertional mutagenesis. This report demonstrates the efficacy of a nonintegrating, minicircle (MC) DNA vector that is resistant to epigenetic gene silencing in vivo. To achieve sustained expression of the immunogenic IDUA protein we investigated the use of a tissue-specific promoter in conjunction with microRNA target sequences. The inclusion of microRNA target sequences resulted in a slight improvement in long-term expression compared to their absence. However, immune modulation by costimulatory blockade was required and permitted for IDUA expression in MPS I mice that resulted in the biochemical correction of pathology in all of the organs analyzed. MC gene delivery combined with costimulatory pathway blockade maximizes safety, efficacy, and sustained gene expression and is a new approach in the treatment of lysosomal storage disease.

Effects of nonpathogenic gram-negative bacteriumVitreoscilla filiformislysate on atopic dermatitis: a prospective, randomized, double-blind, placebo-controlled clinical study

Atopic dermatitis (AD) is associated with elevated IgE levels and Th2 responses. The oral administration of nonpathogenic bacteria such as probiotics may improve the course of atopic diseases. It is believed that nonpathogenic bacteria prevent the development of allergic diseases by modulating intestinal immune responses. However, the effects of oral probiotics on AD could not be reproduced in all studies and the direct immunomodulation of the skin-associated immune response by nonpathogenic bacteria has not yet been investigated. We performed a prospective, double-blind, placebo-controlled clinical study with a cream containing a 5% lysate of the nonpathogenic bacteria Vitreoscilla filiformis. Seventy-five volunteers with AD (6-70 years of age) were randomized to receive either V. filiformis cream 5% or vehicle cream daily for 30 days. Efficacy was evaluated by the SCORe of Atopic Dermatitis (SCORAD), transepidermal water loss (TEWL), assessment of microflora, and the patient's assessment of itch and loss of sleep. Compared with placebo, V. filiformis lysate significantly decreased SCORAD levels (P=0.0044) and pruritus (P=0.0171). Active cream significantly decreased loss of sleep from day 0 to day 29 (P=0.0074). Qualitative and quantitative assessment of cutaneous microbial colonization revealed that V. filiformis lysate reduced Staphylococcus aureus colonization of the skin. The skin barrier as determined by TEWL also improved significantly with the cream alone. V. filiformis lysate significantly improved AD. This may be in part due to reduction of S. aureus, but seems to relate in most parts to a direct immunomodulatory effect on skin-associated immune responses.

Human Peripheral Blood Mononuclear Cells Express Nociceptin/Orphanin FQ, but Not μ, δ, or κ Opioid Receptors

In Brief BACKGROUND: Expression of opioid receptors on peripheral blood mononuclear cells (PBMC) is controversial. These receptors are currently classified as classical (MOP/mu/μ, DOP/delta/δ and KOP/kappa/κ) and nonclassical NOP (nociceptin/orphanin FQ; N/OFQ). METHODS: In this volunteer study we probed for the expression of both classical and nonclassical opioid receptors using 1) radioligand binding, 2) specific antibody binding, and 3) polymerase chain reaction-based experimental paradigms. RESULTS: Membranes prepared from PBMC from healthy volunteers did not bind either [3H]diprenorphine (a nonselective radioligand for classical opioid receptors) or [3H]N/OFQ. There was significant concentration-dependent binding of each radioligand to control tissues expressing recombinant MOP and NOP. In addition, using fluorescence-activated cell sorting paradigms, there was no binding of fluorescent naloxone or either of two MOP antibodies to whole PBMC, though fluorescent naloxone did bind to recombinant MOP (as a positive control). Using primers specific for classical and nonclassical opioid receptors, and RNA extracted from the PBMC of 10 healthy volunteers, we were also unable to detect MOP, DOP, and KOP transcripts. In contrast, NOP was detected in all samples. CONCLUSIONS: Despite using several complementary experimental strategies, we failed to demonstrate protein for classical or nonclassical opioid receptors on PBMC from healthy volunteers. We detected NOP mRNA, suggesting low-density NOP expression on these immunocytes. It is possible that N/OFQ, produced by the PBMC itself, may be involved in the control of immune function. IMPLICATIONS: Opioids depress the immune response, but the involvement of opioid receptors on immune cells is controversial. In the blood of volunteers we failed to detect MOP (μ), DOP (δ), KOP (κ) or Nociceptin receptor (NOP) protein, but we did find NOP mRNA. Direct immunomodulation by opioids in health is unlikely to involve classical opioid receptors, but the nociceptin system may represent a new clinical target.

Systemic lupus erythematosus arising during interferon-alpha therapy for cryoglobulinemic vasculitis associated with hepatitis C

We present the case of a 53-year-old woman who developed systemic lupus erythematosus (SLE) after being treated with interferon-alpha (IFN-alpha) for cryoglobulinemic vasculitis associated with hepatitis C virus (HCV) infection. Her cryoglobulinemic vasculitis resolved rapidly with IFN-alpha treatment. However, after 10 months of IFN-alpha therapy, she developed a photosensitive malar rash, oral ulcers, arthralgias, lymphopenia, and anti-SSA autoantibodies. She was diagnosed with SLE induced by IFN-alpha therapy. IFN-alpha was discontinued, she was treated with a short course of prednisone and hydroxychloroquine, and she improved rapidly. This is the first report of IFN-alpha-induced SLE complicating treatment of cryoglobulinemic vasculitis associated with HCV infection. The development of SLE during therapy with IFN-alpha could be due to direct immunomodulation by IFN-alpha, and review of experimental data and prior case reports suggests a pathogenic role for IFN-alpha in SLE.

Chemiluminescent analysis of the antioxidant and immunomodulation effects of several psychotropic drugs on peritoneal macrophages

The present study describes the application of several chemiluminescent (CL) methods for evaluation of antioxidant and immunomodulation effects of psychotropic drugs upon phagocytes: KO2-induced luminal-dependent CL for detection of superoxide anion radicals in a pure chemical system; PMA- and A23187-induced CL of peritoneal macrophages for detection of free radicals in cell suspension; and CL, produced by the luciferase-catalyzed luciferin + ATP reaction, for evaluation of cell viability before and after drug application. These methods provide also a way to investigate the location of drug action. It was found that the psychotropic drugs in fluence the 'oxidative burst' of macrophages through two mechanisms: by expression of drug antioxidant properties and/or by a direct immunomodulation effect.

Trichostrongylus colubriformis extract upregulates TNF-alpha receptor expression and enhances TNF-alpha sensitivity of L929 cells.

Many pathogens have developed strategies to avoid the host's immune system and hence improve their long-term survival. These strategies include antigenic variation, mimicry of host regulatory proteins and production of immunoregulatory molecules. The ruminant gastrointestinal nematode Trichostrongylus colubriformis produces several factors with homology to human immunoregulatory proteins. However, direct immunomodulation by T. colubriformis proteins has not yet been unequivocally demonstrated. Results in the present paper demonstrate that soluble T. colubriformis factors promote proliferation of the TNF-susceptible mouse fibrosarcoma cell line L929, while inhibiting proliferation of all other cell types tested. In addition, T. colubriformis homogenate enhanced the susceptibility of L929 cells to the cytotoxic action of ovine TNF-alpha. Within 1 h of exposure, T. colubriformis factors bind L929 cells in a stable fashion, yet it takes up to 24 h for the cells to become sensitised to TNF-alpha. Interestingly, the increase of both TNF-alpha sensitivity and proliferation of treated L929 cells correlated with an upregulation in expression of TNF-alpha p55 and p75 receptors.