Macrophage Functions in Psoriasis: Lessons from Mouse Models.

Psoriasis is a systemic autoimmune/autoinflammatory disease that can be well studied in established mouse models. Skin-resident macrophages are classified into epidermal Langerhans cells and dermal macrophages and are involved in innate immunity, orchestration of adaptive immunity, and maintenance of tissue homeostasis due to their ability to constantly shift their phenotype and adapt to the current microenvironment. Consequently, both macrophage populations play dual roles in psoriasis. In some circumstances, pro-inflammatory activated macrophages and Langerhans cells trigger psoriatic inflammation, while in other cases their anti-inflammatory stimulation results in amelioration of the disease. These features make macrophages interesting candidates for modern therapeutic strategies. Owing to the significant progress in knowledge, our review article summarizes current achievements and indicates future research directions to better understand the function of macrophages in psoriasis.

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.

Clinical Characteristics Predicting Worse Long-Term Outcomes in Patients with Myocardial Infarction and Non-Obstructive Coronary Arteries (MINOCA).

Non-obstructive coronary artery disease occurs in 3.5-15% of patients presenting with acute myocardial infarction. This group of patients has a poor prognosis. Identification of factors that predict worse outcomes in myocardial infarction with non-obstructive coronary arteries (MINOCA) is therefore important. Patients with a diagnosis of MINOCA (n = 110) were enrolled in this single-center, retrospective registry. Follow-up was performed 12, 24 and 36 months after discharge. The primary composite endpoint was defined as myocardial infarction, coronary revascularization, stroke or TIA, all-cause death, or hospital readmission due to any cardiovascular event. The mean age of the study group was 64.9 (± 13.5) years and 38.2% of patients were male. The occurrence of the primary composite endpoint was 36.4%. In a COX proportional hazards model analysis, older age (p = 0.027), type 2 diabetes (p = 0.013), history of neoplasm (p = 0.004), ST-segment depression (p = 0.018) and left bundle branch block/right bundle branch block (p = 0.004) by ECG on discharge, higher Gensini score (p = 0.022), higher intraventricular septum (p = 0.007) and posterior wall thickness increases (p = 0.001) were shown to be risk factors for primary composite endpoint occurrence. Our study revealed that several factors such as older age, type 2 diabetes, ST-segment depression and LBBB/RBBB in ECG on discharge, higher Gensini score, and myocardial hypertrophy and history of neoplasm may contribute to worse clinical outcomes in MINOCA patients.

Predictors and trends of contrast use and radiation exposure in a large cohort of patients treated with percutaneous coronary interventions: Chronic total occlusion analysis based on a national registry.

BACKGROUND: The aim herein, was to assess predictors and current trends of radiation exposure and total contrast amount use in patients treated with percutaneous coronary intervention within chronic total occlusion (CTO PCI) and non-CTO PCI. METHODS: Based on a nationwide registry (ORPKI), 535,857 patients treated with PCI between 2014 and 2018 were analysed. The study included 12,572 (2.34%) patients treated with CTO PCI. The CTO PCI and non-CTO PCI groups were compared before and after propensity score matching (PSM). Multifactorial mixed regression models were used to assess predictors of contrast amount use and radiation exposure. RESULTS: The mean total contrast dose and radiation exposure decrease reached statistical significance in following years for the CTO PCI (p = 0.002 and p < 0.001) and non-CTO PCI groups (p < 0.001 and p < 0.001). Multifactorial analysis revealed that non-CTO PCI was a strong independent predictor of lower total contrast dose (estimate: -17.41; 95% confidence interval [CI]: -18.45 to -16.49, p < 0.001) and radiation exposure (estimate: -264.28; 95% CI: -273.75 to -254.81, p < 0.001). After PSM, it was confirmed that CTO PCI was an independent predictor of greater radiation exposure (estimate: 328.6; 95% CI: 289.1-368.1; p < 0.001) and total contrast dose (estimate: 30.5; 95% CI: 27.28-33.74; p < 0.001). CONCLUSIONS: Contrast dose and radiation exposure have decreased in previous years with regard to the CTO PCI and non-CTO PCI groups. CTO PCI was found to be an independent predictor of greater total contrast dose and radiation exposure in the overall group of patients treated with PCI.

Orally Administered Exosomes Suppress Mouse Delayed-Type Hypersensitivity by Delivering miRNA-150 to Antigen-Primed Macrophage APC Targeted by Exosome-Surface Anti-Peptide Antibody Light Chains.

We previously discovered suppressor T cell-derived, antigen (Ag)-specific exosomes inhibiting mouse hapten-induced contact sensitivity effector T cells by targeting antigen-presenting cells (APCs). These suppressive exosomes acted Ag-specifically due to a coating of antibody free light chains (FLC) from Ag-activated B1a cells. Current studies are aimed at determining if similar immune tolerance could be induced in cutaneous delayed-type hypersensitivity (DTH) to the protein Ag (ovalbumin, OVA). Intravenous administration of a high dose of OVA-coupled, syngeneic erythrocytes similarly induced CD3+CD8+ suppressor T cells producing suppressive, miRNA-150-carrying exosomes, also coated with B1a cell-derived, OVA-specific FLC. Simultaneously, OVA-immunized B1a cells produced an exosome subpopulation, originally coated with Ag-specific FLC, that could be rendered suppressive by in vitro association with miRNA-150. Importantly, miRNA-150-carrying exosomes from both suppressor T cells and B1a cells efficiently induced prolonged DTH suppression after single systemic administration into actively immunized mice, with the strongest effect observed after oral treatment. Current studies also showed that OVA-specific FLC on suppressive exosomes bind OVA peptides suggesting that exosome-coating FLC target APCs by binding to peptide-Ag-major histocompatibility complexes. This renders APCs capable of inhibiting DTH effector T cells. Thus, our studies describe a novel immune tolerance mechanism mediated by FLC-coated, Ag-specific, miRNA-150-carrying exosomes that act on the APC and are particularly effective after oral administration.

Perspectives in Manipulating EVs for Therapeutic Applications: Focus on Cancer Treatment.

Extracellular vesicles (EVs) receive special attention from oncologists due to their assumed usefulness as prognostic markers, vaccines to induce anti-cancer immune response, and physiological delivery tools. The latter application, which supports the reduction of side effects of treatment, is still fraught with many challenges, including established methods for loading EVs with selected cargo and directing them towards target cells. EVs could be loaded with selected cargo either in vitro using several physicochemical techniques, or in vivo by modification of parental cell, which may have an advantage over in vitro procedures, since some of them significantly influence EVs' properties. Otherwise, our research findings suggest that EVs could be passively supplemented with micro RNAs (miRNAs) or miRNA antagonists to induce expected biological effect. Furthermore, our observations imply that antigen-specific antibody light chains could coat the surface of EVs to increase the specificity of cell targeting. Finally, the route of EVs' administration also determines their bioavailability and eventually induced therapeutic effect. Besides, EV membrane lipids may possibly possess immune adjuvant activity. The review summarizes the current knowledge on the possibilities to manipulate EVs to use them as a delivery tool, with the special emphasis on anti-cancer therapy.

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.

Intravenously delivered mesenchymal stem cell-derived exosomes target M2-type macrophages in the injured spinal cord.

In a previous report we showed that intravenous infusion of bone marrow-derived mesenchymal stem cells (MSCs) improved functional recovery after contusive spinal cord injury (SCI) in the non-immunosuppressed rat, although the MSCs themselves were not detected at the spinal cord injury (SCI) site [1]. Rather, the MSCs lodged transiently in the lungs for about two days post-infusion. Preliminary studies and a recent report [2] suggest that the effects of intravenous (IV) infusion of MSCs could be mimicked by IV infusion of exosomes isolated from conditioned media of MSC cultures (MSCexos). In this study, we assessed the possible mechanism of MSCexos action on SCI by investigating the tissue distribution and cellular targeting of DiR fluorescent labeled MSCexos at 3 hours and 24 hours after IV infusion in rats with SCI. The IV delivered MSCexos were detected in contused regions of the spinal cord, but not in the noninjured region of the spinal cord, and were also detected in the spleen, which was notably reduced in weight in the SCI rat, compared to control animals. DiR "hotspots" were specifically associated with CD206-expressing M2 macrophages in the spinal cord and this was confirmed by co-localization with anti-CD63 antibodies labeling a tetraspanin characteristically expressed on exosomes. Our findings that MSCexos specifically target M2-type macrophages at the site of SCI, support the idea that extracellular vesicles, released by MSCs, may mediate at least some of the therapeutic effects of IV MSC administration.

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.

EROSION Study (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion): A 1-Year Follow-Up Report.

BACKGROUND: The initial EROSION study (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion) demonstrated that patients with acute coronary syndrome caused by plaque erosion might be stabilized with aspirin and ticagrelor without stenting for ≤1 month. However, a long-term evaluation of outcomes is lacking. The aim of this study was to assess whether the initial benefit of noninterventional therapy for patients with acute coronary syndrome caused by plaque erosion is maintained for ≤1 year. METHODS AND RESULTS: Among 53 patients who completed clinical follow-up, 49 underwent repeat optical coherence tomography imaging at 1 year. Median residual thrombus volume decreased significantly from 1 month to 1 year (0.3 mm3 (0.0-2.0 mm3] versus 0.1 mm3 [0.0-2.0 mm3]; P=0.001). Almost half of the patients (46.9%) had no residual thrombus at 1 year. Minimal effective flow area remained unchanged (2.1 mm2 [1.5-3.8 mm2] versus 2.1 mm2 [1.6-4.0 mm2]; P=0.152). Among 53 patients, 49 (92.5%) remained free from major adverse cardiovascular event for ≤1 year: 3 (5.7%) patients required revascularization because of exertional angina and 1 (1.9%) patient had gastrointestinal bleeding. CONCLUSIONS: One-year follow-up optical coherence tomography demonstrated a further decrease in thrombus volume between 1-month and 1-year follow-up. A majority (92.5%) of patients with acute coronary syndrome caused by plaque erosion managed with aspirin and ticagrelor without stenting remained free of major adverse cardiovascular event for ≤1 year. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02041650.

The impact of advanced opioid drugs and analgesic adjuvants on murine macrophage oxygen burst.

Macrophages (Mf) are a versatile group of phagocytic cells responsible for fulfilling a variety of immune functions, most notably for mounting the initial anti-microbial response and for the clearance of cellular debris and apoptotic bodies. The key processes for fulfilling these functions include the production of reactive oxygen intermediates (ROIs) and nitric oxide (NO). Mf also express a variety of receptors, including opioid, serotonin, and norepinephrine receptors, and thus can react to various substances. Our study aimed to examine the effects of oxycodone and buprenorphine on the production ROIs and NO by Mf from intraperitoneally-treated mice, as compared to the previously studied morphine, fentanyl, and methadone, as well as the effects of the analgesic adjuvants gabapentin, amitriptyline, and venlafaxine. ROIs was estimated via luminol and lucigenin dependent chemiluminescence assay, and NO secretion was estimated via a colorimetric method utilizing a modified Griess reaction. We observed an overall decrease in both ROIs and NO production by Mf from adjuvant-treated mice, especially with amitriptyline. Opioids, however, resulted in enhanced ROIs production and mixed NO secretion, with oxycodone and buprenorphine have the least immunomodulatory effects. As ROIs and NO are potent mediators of Mf activity during the innate immune response, our current results express great translational potential. Our results suggest that OPs administration may boost Mf anti-microbial response. On the other hand, during sterile in ammation, enhanced generation of ROIs by Mf influenced by opioids may increase the risk of tissue damage, but co-administration of adjuvants could abolish this adverse effect.

Differences in coronary plaque characteristics between patients with and those without peripheral arterial disease.

INTRODUCTION: Cardiovascular mortality of patients with combined peripheral arterial disease (PAD) and coronary artery disease (CAD) is twice as high as that in those with either disease alone. It is known that patients with PAD undergoing percutaneous coronary intervention have a higher incidence of adverse cardiac events such as myocardial infarction or target vessel revascularization. OBJECTIVE: In this study, we compared the detailed characteristics of culprit and nonculprit plaques between patients with and those without PAD using optical coherence tomography. PATIENTS AND METHODS: We performed propensity score matching using the following variables: (i) age; (ii) sex; (iii) clinical presentation; (iv) diabetes mellitus; (v) hyperlipidemia; (vi) smoking; (vii) hypertension; (viii) BMI; and (ix) coronary lesion location. Finally, we matched 34 culprit lesions and 30 nonculprit lesions in patients with PAD to 68 culprit lesions and 60 nonculprit lesions in patients without PAD (1 : 2 ratio). RESULTS: In culprit lesions, PAD patients when compared with those without PAD had a higher prevalence of lipid-rich plaque (73.5 vs. 51.5%; P=0.033), higher lipid index (1744±1110 vs. 1246±656; P=0.043), calcification (79.4 vs. 58.8%; P=0.039), macrophage accumulation (70.6 vs. 48.5%; P=0.034), and cholesterol crystals (32.4 vs. 10.3%; P=0.006). In nonculprit lesions, PAD patients had a higher prevalence of calcification (76.7 vs. 55.0%; P=0.046), macrophage accumulation (63.3 vs. 38.3%; P=0.025), and cholesterol crystals (36.7 vs. 16.7%; P=0.034). CONCLUSION: Our study suggests greater coronary plaque vulnerability in both culprit and nonculprit lesions in patients with PAD. This observation underscores the need for more aggressive risk management in patients with combined PAD and coronary artery disease.

The role of macrophages in anti-inflammatory activity of antidepressant drugs.

Depression is a common disease influencing patients' quality of life, whose etiology involves complex interactions of environmental, genetic and immunological factors. The latter factors include proinflammatory activation of monocytes and macrophages and increased serum levels of proinflammatory cytokines, altogether formulated as the "macrophage theory of depression". Our current review summarizes the impact of the most commonly used antidepressant drugs on the immune response with special emphasis on the role of macrophages in the clinically observed effects. The anti-inflammatory action of antidepressants mainly results from their direct interaction with immune cells and from changes in the concentration and the relations of neurotransmitters sensed by these cells. The summarized data revealed that Mφs are one of the leading cell populations involved in drug-mediated immune effects that can be observed both in subjects with depression as well as in individuals not suffering from depression. Thus, currently reviewed immunomodulatory effects of the experimental use of different antidepressant drugs suggest the possibility of utilizing them in complex therapeutic strategies dedicated to various inflammatory and immune-mediated diseases. It is worth noting that an excessive inflammatory reaction is also associated with the pathogenesis of various cardiovascular, metabolic and neuro-endocrine diseases. Thus, the inclusion of antidepressants in the complex therapy of these disorders may have beneficial effects through the enhancement of the mood of the patient and alleviation of chronic inflammation. On the other hand, presented data suggest that the influence of chronically used antidepressants on anti-microbial and anti-tumor immunity could also be taken into consideration.

A subset of AID-dependent B-1a cells initiates hypersensitivity and pneumococcal pneumonia resistance.

We propose that there is a special B-1a B cell subset ("sB-1a" cells) that mediates linked processes very early after immunization to initiate cutaneous contact sensitivity (CS), delayed-type hypersensitivity (DTH), and immune resistance to pneumococcal pneumonia. Our published data indicate that in CS and DTH, these initiating processes are required for elicitation of the delayed onset and late-occurring classical T cell-mediated responses. sB-1a cells resemble memory B2 cells, as they are stimulated within 1 h of immunization and depend on T helper cytokines-uniquely IL-4 from hepatic iNKT cells--for activation and rapid migration from the peritoneal cavity to the spleen to secrete IgM antibody (Ab) and Ab-derived free light chains (FLCs) by only 1 day after immunization. Unlike conventional B-1a (cB-1a) cell-produced IgM natural Ab, IgM Ab produced by sB-1a cells has high Ag affinity owing to immunoglobulin V-region mutations induced by activation-induced cytidine deaminase (AID). The dominant cB-1a cells are increased in immunized AID-deficient mice but do not mediate initiation, CS, or pneumonia resistance because natural Ab has relatively low Ag affinity because of unmutated germ-line V regions. In CS and DTH, sB-1a IgM Ag affinity is sufficiently high to mediate complement activation for generation of C5a that, together with vasoactive mediators such as TNF-α released by FLC-sensitized mast cells, activate local endothelium for extravascular recruitment of effector T cells. We conclude by discussing the possibility of functional sB-1 cells in humans.

[The role of medicaments, exosomes and miRNA molecules in modulation of macrophage immune activity]. / Rola leków, egzosomów i czasteczek miRNA w modulacji aktywnosci immunologicznej makrofagów.

Macrophages play an important role in innate immunity, in induction and orchestration of acquired immune response as well as in the maintenance of tissue homeostasis. Macrophages as antigen presenting cells induce or inhibit the development of immune response and as effector cells play an important role in innate immunity to infectious agents and in delayed--type hypersensitivity as well. Thus, either up- or down-regulation of their activity leads to the impairment of different biological processes. This often results in the development of immunological diseases or inflammatory response associated with metabolic, cardiovascular or neuroendocrine disorders. Therefore, the possibility of modulation of macrophage function should allow for elaboration of new effective therapeutic strategies. Noteworthy, interaction of medicaments with macrophages may directly mediate their therapeutic activity or is an additional beneficial effect increasing efficacy of treatment. Further, macrophage differentiation is regulated by miRNA-223, while expression of miRNA-146 and miRNA-155 may modulate and/or be a result of the current cell phenotype. Present review is focused on the current knowledge about the action of medicaments, microRNA molecules, exosomes and related vesicles on macrophages leading to modulation of their biological activity.

Exosomes as mediators of intercellular communication: clinical implications.

Cells of multicellular organisms exchange informative signals by diverse mechanisms. Recent findings uncovered the special role of extracellular vesicles, especially exosomes, in intercellular communication. Exosomes, present in all tested human bodily fluids, carry various functional compounds including proteins, lipids, and diverse RNA molecules. The composition of exosome cargo in vivo is likely formed by a regulated selection of specific components and can express the current status of the exosome-secreting cell. Therefore, particular emphasis is now placed on the extremely high potential of exosomes as essentially noninvasive prognostic and diagnostic biomarkers, but also as therapeutic nanocarriers, especially after the discovery that their cargo as well as cell-targeting specificity could be shaped in vitro. In addition, targeting the exosomes mediating pathological intercellular communication may also express high therapeutic potential. Hence, numerous studies are conducted to explore the profile and function of exosomes and their cargo in health and disease and to shape their properties to facilitate their clinical application. The present review summarizes the current knowledge on the role of exosomes in different physiological and pathological mechanisms of intercellular communication with a particular focus on the use of exosomes in the diagnosis and treatment of various inflammatory, cardiovascular, metabolic, and neurodegenerative disorders as well as malignant neoplasms.

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.

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.