Hypotensive drugs mitigate the high-sodium diet-induced pro-inflammatory activation of mouse macrophages in vivo.

Nowadays, there is an increasing emphasis on the need to alleviate the chronic inflammatory response to effectively treat hypertension. However, there are still gaps in our understanding on how to achieve this. Therefore, research on interaction of antihypertensive drugs with the immune system is extremely interesting, since their therapeutic effect could partly result from amelioration of hypertension-related inflammation, in which macrophages seem to play a pivotal role. Thus, current comprehensive studies have investigated the impact of repeatedly administered hypotensive drugs (captopril, olmesartan, propranolol, carvedilol, amlodipine, verapamil) on macrophage functions in the innate and adaptive immunity, as well as if drug-induced effects are affected by a high-sodium diet (HSD), one of the key environmental risk factors of hypertension. Although the assayed medications increased the generation of reactive oxygen and nitrogen intermediates by macrophages from standard fed donors, they reversed HSD-induced enhancing effects on macrophage oxidative burst and secretion of pro-inflammatory cytokines. On the other hand, some drugs increased macrophage phagocytic activity and the expression of surface markers involved in antigen presentation, which translated into enhanced macrophage ability to activate B cells for antibody production. Moreover, the assayed medications augmented macrophage function and the effector phase of contact hypersensitivity reaction, but suppressed the sensitization phase of cell-mediated hypersensitivity under HSD conditions. Our current findings contribute to the recognition of mechanisms, by which excessive sodium intake affects macrophage immune activity in hypertensive individuals, and provide evidence that the assayed medications mitigate most of the HSD-induced adverse effects, suggesting their additional protective therapeutic activity.

Low-frequency electromagnetic fields influence the expression of calcium metabolism related proteins in leukocytic cell lines.

Our study aimed to verify the hypothesis concerning low-frequency magnetic fields (LF-MFs)-related changes in cell viability through the biomechanism(s) based on calcineurin (CaN)-mediated signaling pathways triggered via ROS-like molecules. For experiments, Mono Mac 6 and U937 leukocytic cell lines were chosen and exposed to various LF-MFs and/or puromycin (PMC). The protein expression level of key regulatory proteins of calcium metabolism was examined by Western Blot analysis. In turn, the reactive oxygen species (ROS) and cell viability parameters were evaluated by cytochrome C reduction assay and flow cytometry, respectively. The simultaneous action of applied MF and PMC influenced cell viability in a MF-dependent manner. The changes in cell viability were correlated with protein expression and ROS levels. It was verified experimentally that applied stress stimuli influence cell susceptibility to undergo cell death. Moreover, the evoked bioeffects might be recognized as specific to both types of leukocyte populations.

Immunomodulation by tramadol combined with acetaminophen or dexketoprofen: In vivo animal study.

Among other functions, macrophages remove foreign particles, including medications, from the circulation, making them an important target for immunomodulatory molecules. Currently, growing evidence suggests that analgesics affect the activity of immune cells not directly related to pain, and thus may induce unwanted immunosuppression in patients at risk. However, the immunomodulatory effects resulting from macrophage targeting by these drugs are understudied. Therefore, the current study investigated the immune effects induced in healthy mice by repeated administration of tramadol alone or in combination with acetaminophen or dexketoprofen. We observed that drug administration decreased the percentage of infiltrating macrophages in favor of resident macrophages in peritoneal exudates. While all drugs reduced the number of infiltrating macrophages that phagocytosed sheep red blood cells (SRBC), their administration increased the effectiveness of phagocytosis, and treatment with acetaminophen with or without tramadol elevated the expression of MHC class II by Mac3+ macrophages. Interestingly, SRBC-pulsed macrophages from mice treated with tramadol combined with acetaminophen potently activated SRBC-specific B cells in humoral response, and administration of these drugs to recipients of contact hypersensitivity effector cells augmented the resulting cellular immune response. In addition, tramadol administered alone or with dexketoprofen enhanced the spontaneous release of pro-inflammatory cytokines by macrophages. Our current research findings demonstrate that tramadol therapy in combination with acetaminophen or dexketoprofen has a relatively low risk of causing immunosuppressive side effect because the drugs slightly reduce the inflammatory reaction of macrophages but do not impair their ability to activate the adaptive immune responses.

Investigation of the Immunogenic Properties of Ovalbumin Modified by Urban Airborne Particulate Matter.

Exposure to air particulate matter (PM) is linked to the blood oxidative stress and systemic inflammation. The aim of this study was to elucidate whether oxidative PM modification of ovalbumin (OVA), the major antioxidant serum protein, may alter its antigenicity and/or immunogenicity. Ovalbumin was exposed via dialysis to the standard urban PM (SRM 1648a) or to PM with removed organic content (encoded as LAP). Both structural changes and biological properties of PM-modified OVA were measured. T lymphocytes and dendritic cells (the major antigen-presenting cells) isolated from C57BL/6 and OT-II (323-339 epitope) OVA-specific T cell receptor (TCR)-transgenic mice were used to test the effect of PM on OVA immunogenicity. The immunogenicity of both SRM 1648a and LAP-modified OVA was significantly higher than that of control OVA, as measured by the epitope-specific T cell proliferation and interferon γ production by the stimulated cells. This effect was associated with mild oxidative changes in the carrier molecule outside the structure of the OVA epitope and with increased resistance to proteolysis of PM-modified OVA. Interestingly, dendritic cells showed enhanced capacity for the uptake of proteins when the cells were cultured with PM-modified OVA. Our results suggest that the enhanced immunogenicity of PM-modified OVA is not associated with altered antigenicity or antigen presentation. However, it may result from slower degradation and longer persistence of modified antigens in dendritic cells. Whether this phenomenon is associated with enhanced risk prevalence of autoimmune diseases observed in the areas with high urban PM pollution needs to be explained.

The Effect of Inhaled Air Particulate Matter SRM 1648a on the Development of Mild Collagen-Induced Arthritis in DBA/J Mice.

Air pollution is considered to be one of a risk factor for rheumatoid arthritis (RA). Collagen-induced arthritis (CIA) is commonly used as a mouse model of human RA. However, the impact of specific particulate matter (PM) components on the incidence and severity of RA has still not been established. The aim of this study was to develop an experimental model of CIA suitable to test arthritogenicity of inhaled PM. A mild form of CIA was induced in DBA1/J mice inhaled with various components of SRM 1648a PM. The incidence and severity of arthritis was assessed, and the selected serum markers of autoimmunity and inflammation were determined. Clinical arthritis was observed from the booster CII immunisation onward. Anti-cyclic citrullinated peptide antibodies, a diagnostic marker of RA, were detected in serum of these mice. All inhaled pollutants, crude PM, PM with reduced organic content, ferric, and silica nanoparticles markedly increased CIA incidence and severity. The fastest progression of CIA development was caused by crude PM and was linked to enhanced serum levels of anti-CII IgG, the prominent arthritogenic autoantibodies. On the other hand, inhaled nanoparticles enhanced serum levels of TNFα, a major proinflammatory arthritogenic cytokine. We recommend this experimental model of mild CIA to test the mechanisms of arthritis exacerbation by inhaled air pollutants. Further studies are necessary to determine whether PM-aggravated arthritis is caused by inflammatory mediators translocated from inflamed lung into systemic circulation or whether PM translocated into the bloodstream directly exacerbate joint inflammation.

Antibodies Enhance the Suppressive Activity of Extracellular Vesicles in Mouse Delayed-Type Hypersensitivity.

Previously, we showed that mouse delayed-type hypersensitivity (DTH) can be antigen-specifically downregulated by suppressor T cell-derived miRNA-150 carried by extracellular vesicles (EVs) that target antigen-presenting macrophages. However, the exact mechanism of the suppressive action of miRNA-150-targeted macrophages on effector T cells remained unclear, and our current studies aimed to investigate it. By employing the DTH mouse model, we showed that effector T cells were inhibited by macrophage-released EVs in a miRNA-150-dependent manner. This effect was enhanced by the pre-incubation of EVs with antigen-specific antibodies. Their specific binding to MHC class II-expressing EVs was proved in flow cytometry and ELISA-based experiments. Furthermore, by the use of nanoparticle tracking analysis and transmission electron microscopy, we found that the incubation of macrophage-released EVs with antigen-specific antibodies resulted in EVs' aggregation, which significantly enhanced their suppressive activity in vivo. Nowadays, it is increasingly evident that EVs play an exceptional role in intercellular communication and selective cargo transfer, and thus are considered promising candidates for therapeutic usage. However, EVs appear to be less effective than their parental cells. In this context, our current studies provide evidence that antigen-specific antibodies can be easily used for increasing EVs' biological activity, which has great therapeutic potential.

Exopolysaccharide from Lactobacillus rhamnosus KL37 Inhibits T Cell-dependent Immune Response in Mice.

Exopolysaccharides (EPSs), major components of the bacterial biofilm, display strong strain-specific immunomodulatory properties. Previously, we have shown that crude EPS derived from Lactobacillus rhamnosus KL37 depresses the production of arthritogenic anti-collagen IgG and ameliorates collagen-induced arthritis (CIA) in DBA/1 mice, when lipopolysaccharide (LPS) was used as adjuvant. In this study, we used highly purified EPS from L. rhamnosus KL37 (EPS-37) to verify its anti-inflammatory properties and the ability to suppress T cell-dependent humoral response. We have employed the model of active CIA, in which mice immunized with type II collagen (CII) along with LPS were treated with pure EPS-37. Intravenous administration of purified EPS-37 markedly ameliorated arthritis and reduced CII-specific antibody production. EPS-37 injected subcutaneously reduced the clinical symptoms of CIA but without the reduction of arthritogenic antibodies. In addition, the effect of EPS-37 on T-cell functions was tested ex vivo and in vitro. EPS-37 inhibited the in vitro proliferation of T cells activated both in vivo (CII immunization) and in vitro (antigen/mitogen), and markedly reduced the production of interferon (IFN)-γ. These results together with other reports suggest that anti-inflammatory potential of EPS-37 depends on its ability to inhibit either one or the other or both possible inflammatory signaling pathways. Namely, Th1 → IFN-γ → M1 inflammatory macrophages → arthritis and/or Th1 → IFN-γ → B cells → arthritogenic antibodies → arthritis. We suggest that L. rhamnosus KL37 EPS might be utilized to control T cell-dependent immune responses in various inflammatory diseases. However, the most effective route of EPS-37 administration needs to be tailored for a given disorder.

Syngeneic red blood cell-induced extracellular vesicles suppress delayed-type hypersensitivity to self-antigens in mice.

BACKGROUND: At present, the role of autologous cells as antigen carriers inducing immune tolerance is appreciated. Accordingly, intravenous administration of haptenated syngeneic mouse red blood cells (sMRBC) leads to hapten-specific suppression of contact hypersensitivity (CHS) in mice, mediated by light chain-coated extracellular vesicles (EVs). Subsequent studies suggested that mice intravenously administered with sMRBC alone may also generate regulatory EVs, revealing the possible self-tolerogenic potential of autologous erythrocytes. OBJECTIVES: The current study investigated the immune effects induced by mere intravenous administration of a high dose of sMRBC in mice. METHODS: The self-tolerogenic potential of EVs was determined in a newly developed mouse model of delayed-type hypersensitivity (DTH) to sMRBC. The effects of EV's action on DTH effector cells were evaluated cytometrically. The suppressive activity of EVs, after coating with anti-hapten antibody light chains, was assessed in hapten-induced CHS in wild-type or miRNA-150-/- mice. RESULTS: Intravenous administration of sMRBC led to the generation of CD9 + CD81+ EVs that suppressed sMRBC-induced DTH in a miRNA-150-dependent manner. Furthermore, the treatment of DTH effector cells with sMRBC-induced EVs decreased the activation of T cells but enhanced their apoptosis. Finally, EVs coated with antibody light chains inhibited hapten-induced CHS. CONCLUSIONS AND CLINICAL RELEVANCE: The current study describes a newly discovered mechanism of self-tolerance induced by the intravenous delivery of a high dose of sMRBC that is mediated by EVs in a miRNA-150-dependent manner. This mechanism implies the concept of naturally occurring immune tolerance, presumably activated by overloading of the organism with altered self-antigens.

Analgesic adjuvants modulate morphine-induced immune effects in mice.

BACKGROUND: Macrophages, involved in the pathogenesis of pain, express a variety of receptors enabling responsiveness to certain medications, including adjuvant analgesics (AAs), that are effective in neuropathic pain and include drugs not primarily indicated for pain treatment, such as anticonvulsants or antidepressants. Their analgesic effects are likely associated with immunomodulatory activity, that remain undefined. Thus, current research aimed at examining the impact of AAs on morphine-induced effects exerted on mouse immunity. METHODS: Macrophages from mice treated with morphine with or without gabapentin, amitriptyline or venlafaxine, were either subjected to phagocytosis assay, cultured to evaluate the generation of cytokines, or were pulsed with either corpuscular antigen or hapten and transferred to naive recipients to induce humoral or cellular response, respectively. Active contact hypersensitivity was also elicited in drug-treated mice. RESULTS: We observed that repeatedly administered morphine and AAs reduced antigen phagocytosis by macrophages. Further, amitriptyline with morphine enhanced basal secretion of cytokines by macrophages, and all drugs tended to decrease LPS-stimulated release of pro-inflammatory cytokines. Morphine and AAs impacted the expression of phagocytosis and antigen-presentation markers on macrophages, which led to the reduced ability of morphine-affected macrophages to induce B-cell secretion of specific antibodies, and the addition of AAs strengthened this effect. Finally, gabapentin and venlafaxine suppressed the contact hypersensitivity reaction, while amitriptyline seemed to have the opposite effect. CONCLUSIONS: Our study demonstrated a significant anti-inflammatory activity of AAs across a broad spectrum of macrophage immune functions, which is likely critical to their analgesic activity supporting the beneficial effect of morphine.

Delayed-Type Hypersensitivity Underlying Casein Allergy Is Suppressed by Extracellular Vesicles Carrying miRNA-150.

In patients with non-IgE-mediated milk allergy, a cellular mechanism of delayed-type hypersensitivity (DTH) is considered. Recent findings prove that cell-mediated reactions can be antigen-specifically inhibited by extracellular vesicles (EVs) carrying miRNA-150. We sought to establish a new mouse model of DTH to casein and test the possibility of antigen-specific suppression of the inflammatory reaction. To produce soluble antigenic peptides, casein was subjected to alkaline hydrolysis. DTH reaction to casein was induced in CBA, C57BL/6, and BALB/c mice by intradermal (id) injection of the antigen. Cells collected from spleens and lymph nodes were positively or negatively selected and transferred to naive recipients intravenously (iv). CBA mice were tolerized by iv injection of mouse erythrocytes conjugated with casein antigen and following id immunization with the same antigen. Suppressive EVs were harvested from cell cultures and serum of tolerized donors by means of ultrafiltration and ultracentrifugation for further therapeutic utilization. The newly established mouse model of DTH to casein was mediated by CD4+ Th1 cells and macrophages, while EVs produced by casein-tolerized animals effectively suppressed effector cell response, in an miRNA-150-dependent manner. Altogether, our observations contribute to the current understanding of non-IgE-mediated allergy to casein and of the possibilities to downregulate this reaction.

Air particulate matter SRM 1648a primes macrophages to hyperinflammatory response after LPS stimulation.

OBJECTIVE: Exposure to air particulate matter (PM) is associated with chronic inflammatory and autoimmune diseases. Macrophages are responsible for the regulation of chronic inflammation. However, whether PM affects macrophage polarization remains unclear. The aim of this study was to evaluate whether nontoxic concentrations of urban PM are able to prime macrophages to altered inflammatory response upon LPS challenge. METHODS: We used two forms of the urban particulate matter SRM 1648a, intact PM and PM deprived of organic compounds (PM∆C). Peritoneal murine macrophages were exposed to different concentrations of PM for 24 h and then challenged with LPS. Production of inflammatory mediators by macrophages was measured to test immunostimulatory/priming capacity of PM. RESULTS: Particulate matter used at non-cytotoxic concentrations induced a dose-dependent production of proinflammatory cytokines (TNF-α, IL-6, IL-12p40). By contrast, PM∆C were not able to stimulate macrophages. However, macrophages primed with both forms of PM show proinflammatory response upon LPS challenge. CONCLUSIONS: Our data indicate that exposure of macrophages to low concentrations of PM may prime the cells to hyperinflammatory response upon contact with LPS. Further studies are necessary to explain whether the exposure of patients suffering from chronic inflammatory diseases to particulate matter is responsible for the exacerbation of clinical symptoms during bacterial infections.

Data supporting the understanding of modulatory function of opioid analgesics in mouse macrophage activity.

The data presented herein expand the current understanding of the modulatory function of opioid drugs in mouse macrophage activity described in our relevant research article (Filipczak-Bryniarska et al., 2017) [1], in which we characterize the influence of morphine, buprenorphine and oxycodone on humoral and cell-mediated immune response in mice. Among other things, we have shown the effects of treatment with assayed analgesics on macrophage ability to induce antigen-specific B-cell response to sheep red blood cells as well as to generate reactive oxygen intermediates and nitric oxide. The current data demonstrate the effects of morphine, buprenorphine or oxycodone administration on phagocytosis of sheep red blood cells and zymosan by mouse macrophages, supplementing the data on immune modulatory capacities of assayed drugs, recently reported by us (Filipczak-Bryniarska et al., 2017; Kozlowski et al., 2017) [1,2].

In contrast to morphine, buprenorphine enhances macrophage-induced humoral immunity and, as oxycodone, slightly suppresses the effector phase of cell-mediated immune response in mice.

BACKGROUND: Opioid receptors are commonly expressed on various immune cells, macrophages especially. Thus, these cells are prone to stimulation with opioids, which seems to be responsible for opioid-induced immunomodulatory effects. While morphine, fentanyl and methadone influence on mouse immune response was recently studied, little is known about the potential immunomodulatory impact of buprenorphine and oxycodone. AIM: The current research aimed to investigate the influence of buprenorphine and oxycodone on immune responses in mice under homeostatic conditions. METHODS AND RESULTS: Repeated administration of morphine led to intensification of CHS response in actively sensitized mice, while buprenorphine or oxycodone administration exerted the opposite effect. Further, hapten-conjugated macrophages from mice treated with morphine, when transferred into naive recipients, induced more potent CHS response. The enhanced generation of reactive oxygen intermediates and nitric oxide by macrophages from mice treated with buprenorphine, oxycodone or morphine was also shown, along with increased release of IL-6, TNFα and TGFß. Treatment with opioids altered expression of antigen phagocytosis and presentation markers. Finally, the inhibitory effect of morphine treatment on induction of humoral immunity by macrophages was demonstrated, while oxycodone failed to influence humoral immune response and buprenorphine actually enhanced B-cell activation. CONCLUSIONS: Current observations confirm that macrophages greatly contribute to immunomodulatory effects of opioids. Studies on immunomodulation by opioids have great importance related to the evaluation of its beneficial and adverse effects on patient condition. Our research showed that oxycodone exerts the weakest immunomodulatory properties, allowing us to assume this drug as safer than morphine during prolonged therapy.

Air pollution, oxidative stress, and exacerbation of autoimmune diseases.

A number of epidemiological studies have shown a strong association between exposure to ambient airborne particulate matter (PM 2.5, PM < 1.0) and lung or cardiovascular diseases characterised by high mortality and morbidity. However, much less is known about the role of air pollution in the pathogenesis of autoimmune diseases, which constitutes a significant problem in modern society. This paper summarises the state of current research regarding the influence of PM on the development and/or progression of autoimmune diseases. A brief review of the great body of research concerning pathogenesis of autoimmune disorders is presented. Then, the scope of our review is narrowed to the research related to the impact of particulate matter on oxidative and nitrosative stress, as well as exacerbation of chronic inflammation, because they can contribute to the development of autoimmune diseases. Moreover, we discuss the impact of various components of PM (metal, organic compounds) on PM toxicity and the ability to generate oxidants.

Changes in cell death of peripheral blood lymphocytes isolated from children with acute lymphoblastic leukemia upon stimulation with 7 Hz, 30 mT pulsed electromagnetic field.

Pulsed electromagnetic field (PEMF) influenced the viability of proliferating in vitro peripheral blood mononuclear cells (PBMCs) isolated from Crohn's disease patients as well as acute myeloblastic leukemia (AML) patients by induction of cell death, but did not cause any vital changes in cells from healthy donors. Experiments with lymphoid U937 and monocytic MonoMac6 cell lines have shown a protective effect of PEMF on the death process in cells treated with death inducers. The aim of the current study was to investigate the influence of PEMF on native proliferating leukocytes originating from newly diagnosed acute lymphoblastic leukemia (ALL) patients. The effects of exposure to PEMF were studied in PBMCs from 20 children with ALL. PBMCs were stimulated with three doses of PEMF (7 Hz, 30 mT) for 4 h each with 24 h intervals. After the last stimulation, the cells were double stained with annexin V and propidium iodide dye to estimate viability by flow cytometric analysis. The results indicated an increase of annexin V positive as well as double stained annexin V and propidium iodide positive cells after exposure to threefold PEMF stimulation. A low-frequency pulsed electromagnetic field induces cell death in native proliferating cells isolated from ALL patients. The increased vulnerability of proliferating PBMCs to PEMF-induced interactions may be potentially applied in the therapy of ALL. The analysis of expression of apoptosis-related genes revealed changes in mRNA of some genes engaged in the intrinsic apoptotic pathway belonging to the Bcl-2 family and the pathway with apoptosis-inducing factor (AIF) abundance upon PEMF stimulation of PBMCs.

Macrophages play an essential role in antigen-specific immune suppression mediated by T CD8⁺ cell-derived exosomes.

Murine contact sensitivity (CS) reaction could be antigen-specifically regulated by T CD8(+) suppressor (Ts) lymphocytes releasing microRNA-150 in antibody light-chain-coated exosomes that were formerly suggested to suppress CS through action on macrophages (Mφ). The present studies investigated the role of Mφ in Ts cell-exosome-mediated antigen-specific suppression as well as modulation of Mφ antigen-presenting function in humoral and cellular immunity by suppressive exosomes. Mice depleted of Mφ by clodronate liposomes could not be tolerized and did not produce suppressive exosomes. Moreover, isolated T effector lymphocytes transferring CS were suppressed by exosomes only in the presence of Mφ, demonstrating the substantial role of Mφ in the generation and action of Ts cell regulatory exosomes. Further, significant decrease of number of splenic B cells producing trinitrophenyl (TNP) -specific antibodies with the alteration of the ratio of serum titres of IgM to IgG was observed in recipients of exosome-treated, antigen-pulsed Mφ and the significant suppression of CS was demonstrated in recipients of exosome-treated, TNP-conjugated Mφ. Additionally, exosome-pulsed, TNP-conjugated Mφ mediated suppression of CS in mice pre-treated with a low-dose of cyclophosphamide, suggesting de novo induction of T regulatory (Treg) lymphocytes. Treg cell involvement in the effector phase of the studied suppression mechanism was proved by unsuccessful tolerization of DEREG mice depleted of Treg lymphocytes. Furthermore, the inhibition of proliferation of CS effector cells cultured with exosome-treated Mφ in a transmembrane manner was observed. Our results demonstrated the essential role of Mφ in antigen-specific immune suppression mediated by Ts cell-derived exosomes and realized by induction of Treg lymphocytes and inhibition of T effector cell proliferation.

Distinct effects of Lactobacillus plantarum KL30B and Escherichia coli 3A1 on the induction and development of acute and chronic inflammation.

OBJECTIVE: Enteric bacteria are involved in the pathogenesis of ulcerative colitis. In experimental colitis, a breakdown of the intestinal epithelial barrier results in inflow of various gut bacteria, induction of acute inflammation and finally, progression to chronic colitis. MATERIAL AND METHODS: In the present study we compared pro-inflammatory properties of two bacterial strains isolated from human microbiome, Escherichia coli 3A1 and Lactobacillus plantarum KL30B. The study was performed using two experimental models of acute inflammation: peritonitis in mice and trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats. RESULTS: Both bacterial strains induced massive neutrophil infiltration upon injection into sterile peritoneal cavity. However, peritoneal exudate cells stimulated in vitro with E. coli 3A1, produced far more nitric oxide, than those stimulated with L. plantarum KL30B. Interestingly, distinct effect on the development of TNBS-induced colitis was observed after oral administration of the tested bacteria. Lactobacillus plantarum KL30B evoked strong acute colitis. On the contrary, the administration of E. coli 3A1 resulted in a progression of colitis to chronicity. CONCLUSIONS: Our results show that distinct effects of bacterial administration on the development of ongoing inflammation is strain specific and depends on the final effect of cross-talk between bacteria and cells of the innate immune system.

Enhanced generation of reactive oxygen intermediates by suppressor T cell-derived exosome-treated macrophages.

Macrophages (Mφ) as efficient phagocytes able to present the antigen and playing an effector role induce and orchestrate the immune response also through the release of soluble factors. Recently described T CD8+ cell-derived suppressive exosomes carrying miRNA-150, that act antigen-specifically, seem to inhibit murine contact sensitivity reaction indirectly by affecting antigen presenting cells, especially Mφ. Present studies investigated the influence of suppressive exosomes on secretory activity of Mφ assessed as their ability to generate reactive oxygen intermediates (ROIs), nitric oxide, cytokines as well as their viability and expression of antigen phagocytosis and presentation markers. Interestingly, in vivo and in vitro treatment of Mφ with assayed hapten-specific exosomes affected only ROIs generation, significantly enhancing their production. Current results suggest that ROIs may participate in antigen-specific tolerance mechanism mediated by suppressive T lymphocyte-derived exosome-influenced Mφ, by inhibition of effector T cell proliferation and induction of T regulatory lymphocytes.

The influence of opioids on the humoral and cell-mediated immune responses in mice. The role of macrophages.

BACKGROUND: Our experiments were aimed to test the influence of treatment with different opioids (morphine, fentanyl, methadone) on the humoral and cell-mediated immune responses. METHODS: Mice were treated intraperitoneally (ip) with opioids for several days and next either immunized with sheep red blood cells (SRBC) to test the antibody production or skin-sensitized with hapten picryl chloride (PCL) to induce contact hypersensitivity (CHS). In addition, the effects of opioids on the production of reactive oxygen intermediates (ROIs) and cytokines by peritoneal macrophages (Mf) and on the expression of surface markers on these cells and blood leukocytes were estimated. RESULTS: Opioids caused an enhancement of ROIs and cytokines production when macrophages were stimulated with zymosan or lipopolysaccharide (LPS) and reduced the expression of antigen presentation markers on Mf. Numbers of anti-SRBC plaque forming cells (PFC) and antibodies titres were lower in mice treated with all tested opioids. Depending on the use of particular opioid and the phase of allergic reaction, effects of the treatment on CHS were diverse. While morphine decreased the early and late phases of induction of CHS responses, methadone increased both reactions. In case of the effector phase of CHS, morphine and fentanyl increased both its early and late stages, while methadone decreased the late reaction. Treatment of recipients with opioids had diverse influence on the passive transfer of CHS in these animals. CONCLUSIONS: Our experiments show that the action of opioids on the immune system is a complex phenomenon dependent on such variables as type of opioid, character of response (humoral versus cellular) and types of cells involved. Here Mf seem to play a significant role.

Lactobacillus rhamnosus exopolysaccharide ameliorates arthritis induced by the systemic injection of collagen and lipopolysaccharide in DBA/1 mice.

Oral administration of some probiotic bacteria (e.g. Lactobacillus rhamnosus) attenuates various types of experimental arthritis, including collagen-induced arthritis (CIA) and inhibits arthritogenic autoantibodies. Much less is known about the possible anti-arthritogenic properties of exopolysaccharide (EPS), the major component of lactic bacteria biofilm. In this study, we asked the question whether systemic administration of EPS derived from L. rhamnosus KL37 depresses the production of anti-collagen IgG and affects the development of CIA in DBA/1 mice. Arthritis was induced employing two models of active CIA, in which mice were immunized with type II collagen (CII) either in the presence of lipopolysaccharide (LPS; mild arthritis with moderate CII-specific IgG production) or with Complete Freund's Adjuvant and LPS (severe arthritis with massive CII-specific IgG production). Passive CIA was induced by intravenous injection of CII-specific monoclonal antibodies and LPS. Disease progression, the incidence and severity of arthritis, were determined. Serum concentration of CII-specific IgG was measured by enzyme-linked immunosorbent assay. Systemic administration of EPS markedly reduced CII-specific antibody production. Moreover, EPS significantly ameliorated arthritis in the active models of CIA, especially, when LPS alone was used as an adjuvant. In contrast, when arthritogenic antibodies were injected to mice in high amounts, the effect of EPS on the development of passive CIA was negligible and transient. These results show that EPS can suppress active CIA by the inhibition of arthritogenic antibodies production. Therefore, we suggest that EPS or EPS-producing probiotics may be promising agents for the supporting therapy of patients with rheumatoid arthritis.