Measurement of cytokine secretion, intracellular protein expression, and mRNA in resting and stimulated peripheral blood mononuclear cells

Meta-Analysis of Cytokines and Chemokines in Suicidality: Distinguishing Suicidal Versus Nonsuicidal Patients

BACKGROUND

Major psychiatric disorders are associated with inflammation. Aberrant cytokine and chemokine levels have been associated with psychiatric disorders and suicidal behavior. We performed a meta-analysis of cytokine and chemokine levels in patients with versus without suicidality and patients with suicidality versus healthy controls.

METHODS

We identified articles by searching MEDLINE, PsycINFO, and Thomson Reuters Web of Knowledge databases and the reference lists of identified studies.

RESULTS

Study inclusion criteria were met by 18 studies comprising 583 patients with suicidality, 315 patients without suicidality, and 845 healthy control subjects. Levels of interleukin (IL)-1β and IL-6 were significantly increased in blood and postmortem brain samples of patients with suicidality compared with both patients without suicidality and healthy control subjects (p < .05 for each). In vitro IL-2 production by peripheral blood mononuclear cells was significantly decreased in patients with suicidality compared with both patients without suicidality and healthy controls (p < .01 for each). Cerebrospinal fluid levels of IL-8 were significantly decreased in patients with suicidality versus control subjects (p < .05).

CONCLUSIONS

We found evidence for aberrant cytokine levels in blood, cerebrospinal fluid, and postmortem brain samples of patients with suicidality. Levels of IL-1β and IL-6 were most robustly associated with suicidality, and these cytokines may help distinguish suicidal from nonsuicidal patients. Rigorously designed longitudinal studies are needed to evaluate these associations further.

HIF-1α and PFKFB3 Mediate a Tight Relationship Between Proinflammatory Activation and Anerobic Metabolism in Atherosclerotic Macrophages

OBJECTIVE

Although it is accepted that macrophage glycolysis is upregulated under hypoxic conditions, it is not known whether this is linked to a similar increase in macrophage proinflammatory activation and whether specific energy demands regulate cell viability in the atheromatous plaque.

APPROACH AND RESULTS

We studied the interplay between macrophage energy metabolism, polarization, and viability in the context of atherosclerosis. Cultured human and murine macrophages and an in vivo murine model of atherosclerosis were used to evaluate the mechanisms underlying metabolic and inflammatory activity of macrophages in the different atherosclerotic conditions analyzed. We observed that macrophage energetics and inflammatory activation are closely and linearly related, resulting in dynamic calibration of glycolysis to keep pace with inflammatory activity. In addition, we show that macrophage glycolysis and proinflammatory activation mainly depend on hypoxia-inducible factor and on its impact on glucose uptake, and on the expression of hexokinase II and ubiquitous 6-phosphofructo-2-kinase. As a consequence, hypoxia potentiates inflammation and glycolysis mainly via these pathways. Moreover, when macrophages' ability to increase glycolysis through 6-phosphofructo-2-kinase is experimentally attenuated, cell viability is reduced if subjected to proinflammatory or hypoxic conditions, but unaffected under control conditions. In addition to this, granulocyte-macrophage colony-stimulating factor enhances anerobic glycolysis while exerting a mild proinflammatory activation.

CONCLUSIONS

These findings, in human and murine cells and in an animal model, show that hypoxia potentiates macrophage glycolytic flux in concert with a proportional upregulation of proinflammatory activity, in a manner that is dependent on both hypoxia-inducible factor -1α and 6-phosphofructo-2-kinase.

Peripheral blood mononuclear cell proteome changes in patients with myelodysplastic syndrome

Our aim was to search for proteome changes in peripheral blood mononuclear cells (PBMCs) of MDS patients with refractory cytopenia with multilineage dysplasia. PBMCs were isolated from a total of 12 blood samples using a Histopaque-1077 solution. The proteins were fractioned, separated by 2D SDS-PAGE (pI 4–7), and double-stained. The proteomes were compared and statistically processed with Progenesis SameSpots; then proteins were identified by nano-LC-MS/MS. Protein functional association and expression profiles were analyzed using the EnrichNet application and Progenesis SameSpots hierarchical clustering software, respectively. By comparing the cytosolic, membrane, and nuclear fractions of the two groups, 178 significantly (P < 0.05, ANOVA) differing spots were found, corresponding to 139 unique proteins. Data mining of the Reactome and KEGG databases using EnrichNet highlighted the possible involvement of the identified protein alterations in apoptosis, proteasome protein degradation, heat shock protein action, and signal transduction. Western blot analysis revealed underexpression of vinculin and advanced fragmentation of fermitin-3 in MDS patients. To the best of our knowledge, this is the first time that proteome changes have been identified in the mononuclear cells of MDS patients. Vinculin and fermitin-3, the proteins involved in cell adhesion and integrin signaling, have been shown to be dysregulated in MDS.

Evaluation of Th17-related cytokines and IFNγ production from blood mononuclear cells of moderate and severe asthmatic children reveals methylprednisolone does not decrease IL-22 levels

OBJECTIVE

The aim of this study was to correlate IL-6, IL-17A, IFNγ, and IL-22 production with asthma disease severity and to evaluate if methylprednisolone downregulated cytokine production in peripheral blood mononuclear cells (PBMCs).

METHODS

Forty-two children with chronic persistent asthma and 34 non-asthmatic children were selected. Cytokines were quantified by ELISA from serum or PBMCs supernatants, after the PMA and Ionomycin stimulation, with or without methylprednisolone at 100 µM.

RESULTS

Our data showed undetectable levels of serum cytokines in most patients and controls. In the PBMCs, we have observed a higher production of IL-17A than IL-22 among asthmatics and controls, although it is not statistically significant. IL-6, IFNγ, and IL-17A levels were significantly reduced after methylprednisolone treatment (p = 0.02, 0.03, and 0.03, respectively) in Severe Persistent Asthma (SPA) and in Moderate Persistent Asthma (MPA), (p = 0.007, 0.01, and 0.007, respectively). However, IL-22 levels were unaffected (SPA, p = 0.12 and MPA, p = 0.93).

CONCLUSION

Methylprednisolone downregulated IL-6, IL17A, and IFNγ, but not IL-22, in stimulated PBMCs from asthmatic children indicating that methylprednisolone has no effect on IL-22 production by PBMCs.

A targeted secretome profiling by multiplexed immunoassay revealed that secreted chemokine ligand 2 (MCP-1/CCL2) affects neural differentiation in mesencephalic neural progenitor cells

Chemokines and cytokines, primarily known for their roles in the immune and inflammatory response, have also been identified as key components of the neurogenic niche where they are involved in the modulation of neural stem cell proliferation and differentiation. However, a complete understanding of the functional role played in neural differentiation and a comprehensive profiling of these secreted molecules are lacking. By exploiting the multiplexing capability of magnetic bead-based immunoassays, we have investigated the changes of the expression levels of a set of chemokines and cytokines released from the pluripotent neural cell line mes-c-myc A1 following its differentiation from a proliferating phenotype (A1P) toward a neural (A1D) phenotype. We found a subset of molecules exclusively released from A1P, whereas others were differentially detected in A1P and A1D conditioned media. Among them, we identified monocyte chemoattractant protein-1/chemokine ligand 2 (MCP-1/CCL2) as a proneurogenic factor able to affect neuronal differentiation of A1 cells as well as of neuroblasts from primary cultures and to induce the elongation and/or formation of neuritic processes. Altogether, data are suggestive of a main role played by the CCL2/CCR2 signaling pathway and in general of the network of secreted cytokines/chemokines in the differentiation of neural progenitor cells toward a neural fate.

A review of the application of inflammatory biomarkers in epidemiologic cancer research

Inflammation is a facilitating process for multiple cancer types. It is believed to affect cancer development and progression through several etiologic pathways, including increased levels of DNA adduct formation, increased angiogenesis, and altered antiapoptotic signaling. This review highlights the application of inflammatory biomarkers in epidemiologic studies and discusses the various cellular mediators of inflammation characterizing the innate immune system response to infection and chronic insult from environmental factors. Included is a review of six classes of inflammation-related biomarkers: cytokines/chemokines, immune-related effectors, acute-phase proteins, reactive oxygen and nitrogen species, prostaglandins and cyclooxygenase-related factors, and mediators such as transcription factors and growth factors. For each of these biomarkers, we provide a brief overview of the etiologic role in the inflammation response and how they have been related to cancer etiology and progression within the literature. We provide a discussion of the common techniques available for quantification of each marker, including strengths, weaknesses, and potential pitfalls. Subsequently, we highlight a few under-studied measures to characterize the inflammatory response and their potential utility in epidemiologic studies of cancer. Finally, we suggest integrative methods for future studies to apply multifaceted approaches to examine the relationship between inflammatory markers and their roles in cancer development.

Expression profiles of the immune genes CD4, CD8β, IFNγ, IL-4, IL-6 and IL-10 in mitogen-stimulated koala lymphocytes (Phascolarctos cinereus) by qRT-PCR

Investigation of the immune response of the koala (Phascolarctos cinereus) is needed urgently, but has been limited by scarcity of species-specific reagents and methods for this unique and divergent marsupial. Infectious disease is an important threat to wild populations of koalas; the most widespread and important of these is Chlamydial disease, caused by Chlamydia pecorum and Chlamydia pneumoniae. In addition, koala retrovirus (KoRV), which is of 100% prevalence in northern Australia, has been proposed as an important agent of immune suppression that could explain the koala's susceptibility to disease. The correct balance of T regulatory, T helper 1 (Th1) and Th2 lymphocyte responses are important to an individual's susceptibility or resistance to chlamydial infection. The ability to study chlamydial or KoRV pathogenesis, effects of environmental stressors on immunity, and the response of koalas to vaccines under development, by examining the koala's adaptive response to natural infection or in-vitro stimulation, has been limited to date by a paucity of species- specific reagents. In this study we have used cytokine sequences from four marsupial genomes to identify mRNA sequences for key T regulatory, Th1 and Th2 cytokines interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 10 (IL-10) and interferon gamma (IFNγ) along with CD4 and CD8β. The koala sequences used for primer design showed >58% homology with grey short-tailed opossum, >71% with tammar wallaby and 78% with Tasmanian devil amino acid sequences. We report the development of real-time RT-PCR assays to measure the expression of these genes in unstimulated cells and after three common mitogen stimulation protocols (phorbol myristate acetate/ionomycin, phorbol myristate acetate/phytohemagglutinin and concanavalin A). Phorbol myristate acetate/ionomycin was found to be the most effective mitogen to up-regulate the production of IL-4, IL-10 and IFNγ. IL-6 production was not consistently up-regulated by any of the protocols. Expression of CD4 and CD8β was down-regulated by mitogen stimulation. We found that the reference genes GAPDH and 28s are valid for normalising cytokine expression by koala lymphocytes after mitogen stimulation.

NF-κB enhances hypoxia-driven T-cell immunosuppression via upregulation of adenosine A(2A) receptors

Hypoxia affects inflammation by modulating T-cell activation via the adenosinergic system. We supposed that, in turn, inflammation influences cell hypoxic behavior and that stimulation of T-cells in inflammatory conditions involves the concerted action of the nuclear factor κB (NF-κB) and the related hypoxia-inducible factor 1α (HIF-1α) on the adenosinergic system. We addressed this hypothesis by monitoring both transcription factors and four adenosinergic signaling parameters - namely adenosine, adenosine deaminase (ADA), adenosine A2A receptor (A2AR) and cAMP - in T-cells stimulated using phorbol myristate acetate and phytohemagglutinin and submitted to hypoxic conditions which were mimicked using CoCl2 treatment. We found that cell viability was more altered in stimulated than in resting cells under hypoxia. Detailed analysis showed that: i) NF-κB activation remained at basal level in resting hypoxic cells but greatly increased following stimulation, stimulated hypoxic cells exhibiting the higher level; ii) HIF-1α production induced by hypoxia was boosted via NF-κB activation in stimulated cells whereas hypoxia increased HIF-1α production in resting cells without further activating NF-κB; iii) A2AR expression and cAMP production increased in stimulated hypoxic cells whereas adenosine level remained unchanged due to ADA regulation; and iv) the presence of H2S, an endogenous signaling molecule in inflammation, reversed the effect of stimulation on cell viability by down-regulating the activity of transcription factors and adenosinergic immunosuppression. We also found that: i) the specific A2AR agonist CGS-21680 increased the suppressive effect of hypoxia on stimulated T-cells, the antagonist ZM-241385 exhibiting the opposite effect; and ii) Rolipram, a selective inhibitor of cAMP-specific phosphodiesterase 4, and 8-Br-cAMP, a cAMP analog which preferentially activates cAMP-dependent protein kinase A (PKA), increased T-cell immunosuppression whereas H-89, a potent and selective inhibitor of cAMP-dependent PKA, restored cell viability. Together, these data indicate that inflammation enhances T-cell sensitivity to hypoxia via NF-κB activation. This process upregulates A2AR expression and enhances cAMP production and PKA activation, resulting in adenosinergic T-cell immunosuppression that can be modulated via H2S.

Effects of cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid, linoleic acid, phytanic acid and the combination of various fatty acids on proliferation and cytokine expression of bovine peripheral blood mononuclear cells

Fatty acids may have an impact on immune functions, which is important in times of increased mobilization of body fat, e.g., around parturition. The aim of the present study was to investigate the effects of the CLA isomers cis-9,trans-11 and trans-10,cis-12, phytanic acid (PA), linoleic acid (LA) and a fatty acid (FA) mixture (containing 29.8% palmitic acid, 6.7% palmitoleic acid, 17.4% stearic acid and 46.1% oleic acid) on the proliferation of bovine blood mononuclear cells (PBMC) in vitro using alamar blue (AB) and 5-bromo-2′-deoxyuridine (BrdU) assay. Quantitative real time polymerase chain reaction analyses were performed to evaluate the expression of interleukin (IL)-4, IL-10, interferon (IFN)-γ, tumor necrosis factor (TNF)-α and peroxisome proliferator-activated receptor (PPAR)-γ in response to cis-9,trans-11 and LA. The IC₅₀ values did not differ between the investigated FA, but there were differences within the proliferation in the response of these FA in a concentration range between 20 and 148 µM (e.g., increased proliferation after treatment with lower concentrations of LA). No differences occurred when different FA combinations were tested. ConA stimulation increased the expression of TNF-α and IFN-γ, whereas IL-10 decreased. In general, neither the baseline expression nor the ConA-stimulated mRNA expression of cytokines and PPAR-γ were affected by the FA. In conclusion, all FA inhibit the proliferation of PBMC dose dependently without significantly altering the induced cytokine spectrum of activated bovine PBMC.

Colonic inflammation in Parkinson's disease

Lewy pathology affects the gastrointestinal tract in Parkinson's disease (PD) and data from recent genetic studies suggest a link between PD and gut inflammation. We therefore undertook the present survey to investigate whether gastrointestinal inflammation occurs in PD patients. Nineteen PD patients and 14 age-matched healthy controls were included. For each PD patients, neurological and gastrointestinal symptoms were assessed using the Unified Parkinson's Disease Rating Scale part III and the Rome III questionnaire, respectively and cumulative lifetime dose of L-dopa was calculated. Four biopsies were taken from the ascending colon during the course of a total colonoscopy in controls and PD patients. The mRNA expression levels of pro-inflammatory cytokines (tumor necrosis factor alpha, interferon gamma, interleukin-6 and interleukin-1 beta) and glial marker (Glial fibrillary acidic protein, Sox-10 and S100-beta) were analyzed using real-time PCR in two-pooled biopsies. Immunohistochemical analysis was performed on the two remaining biopsies using antibodies against phosphorylated alpha-synuclein to detect Lewy pathology. The mRNA expression levels of pro-inflammatory cytokines as well as of two glial markers (Glial fibrillary acidic protein and Sox-10) were significantly elevated in the ascending colon of PD patients with respect to controls. The levels of tumor necrosis factor alpha, interferon gamma, interleukin-6, interleukin-1 beta and Sox-10 were negatively correlated with disease duration. By contrast, no correlations were found between the levels of pro-inflammatory cytokines or glial markers and disease severity, gastrointestinal symptoms or cumulative lifetime dose of L-dopa. There was no significant difference in the expression of pro-inflammatory cytokines or glial marker between patients with and without enteric Lewy pathology. Our findings provide evidence that enteric inflammation occurs in PD and further reinforce the role of peripheral inflammation in the initiation and/or the progression of the disease.

Simultaneous detection of cell-secreted TNF-α and IFN-γ using micropatterned aptamer-modified electrodes

Cellular production of such cytokines as interferon (IFN)-γ and tumor necrosis factor (TNF)-α is used to determine disease-specific immune responses and may be used to diagnose infectious diseases such as tuberculosis. In this paper, we describe the development of micropatterned electrodes functionalized with electroactive aptamers for multiplexed detection of immune-cell-produced cytokines. A sequence of electrode deprotection and aptamer incubation steps were used to assemble anti-IFN-γ DNA aptamers and anti-TNF-α RNA aptamers on individually addressable half-ring electrodes. Aptamer molecules were thiolated for assembly on gold and were functionalized with methylene blue redox reporter for electrochemical signal transduction. Specificity of individual sensors to the correct cytokine species was confirmed by exposure to recombinant cytokines. For cell detection experiments, electrode arrays were integrated into microfluidic devices and incubated with immune cells. Design of the surface was such that a small group of ~400 cells attached in the circular adhesion sites surrounded by half-ring electrodes sensing IFN-γ and TNF-α. The microdevice consisted of two parallel microfluidic channels, each channel containing four cell capture/sensing sites. Upon mitogenic activation, secreted IFN-γ and TNF-α molecules were monitored by performing square wave voltammetry (SWV) at different time points at individually addressable electrodes. This biosensing platform was used to analyze the quantity and rate of cytokine release from primary T cells and a monocyte cell line. Upon further development of this platform may be enhanced to enable detection of larger number of cytokines and used to correlate the levels and dynamics of cytokine release in immune cells to diagnosis and treatment of infectious diseases.

Activation of T lymphocytes in atherosclerotic plaques

OBJECTIVE

To decipher the immunologic mechanisms of plaque maturation and rupture, it is necessary to analyze the phenotypes and distribution of individual lymphocytes that migrate to the plaques, as well as their activation at different stages of plaque formation.

METHODS AND RESULTS

We developed a protocol to isolate plaque-residing immune cells and analyze their status using polychromatic flow cytometry. We found that the composition and phenotype of T lymphocytes in the plaques differs from that in blood. CD4 and, in particular, CD8(+) T cells in plaques are highly activated; the fraction of CD8 T cells coexpressing CD25 and human leukocyte antigen-D related in plaques was 6 times as large as in blood.

CONCLUSIONS

The first flow-cytoanalysis of individual T cells in atherosclerotic plaques indicates that plaques represent a separate immunologic compartment from blood with lymphocytes characterized by a high level of T-cell activation, which is compatible with the presence of antigen(s) that trigger infiltration activation of these cells. The ability to isolate and characterize these cells may lead to the identification of such antigens.

Human mesenchymal stem cells from adipose tissue and amnion influence T-cells depending on stimulation method and presence of other immune cells

Mesenchymal stem cells (MSCs) are multipotent progenitor cells exerting immunomodulatory effects on cells of the innate and adaptive immune system. It has been shown that an inflammatory milieu is required for the activation of MSC-mediated immunomodulation, and interferon-γ (IFN-γ) plays an important role in this process. We determined the influence of IFN-γ on human adipose-derived stem cells (ASCs) and human amniotic mesenchymal stromal cells (hAMSCs). We further evaluated the effect of MSCs on stimulated T-cells and peripheral blood mononuclear cells (PBMCs) in a cell-contact independent setting. On IFN-γ treatment, ASCs and hAMSCs possessed significantly higher antiproliferative properties and showed surface characteristics of nonprofessional antigen presenting cells (HLA-DR(+)CD40(med+)CD54(high)) with a possible regulatory phenotype (PD-L1(+)PD-L2(+)). The effect of ASCs and hAMSCs on cytokine secretion and T-cell activation was dependent on stimulation method and cellular context. Although ASCs and hAMSCs highly inhibited cytokine secretion of stimulated PBMCs, this was not observed in the case of purified T-cells. The presence of ASCs even favored the secretion of pro-inflammatory cytokines including IFN-γ by T-cells, although T-cell proliferation was efficiently inhibited. Further, ASCs enhanced the number of CD69(+) T-cells independent of the stimuli and cellular context. Interestingly, ASCs significantly suppressed CD25 expression on phytohemagglutinin stimulated PBMCs but had no effect on αCD3/αCD28 stimulated cells. Depending on the stimulation method and cellular context, immune cells create a specific cytokine milieu in vitro, thus differently influencing MSCs and, in turn, affecting their action on immune cells.

Measurement of serum, liver, and brain cytokine induction, thiamine levels, and hepatopathology in rats exposed to a 4-day alcohol binge protocol

BACKGROUND

 In rodent and human studies, ethanol (EtOH) exposure is associated with elevated brain levels of the magnetic resonance spectroscopy (MRS) signal representing choline-containing compounds (Cho). One interpretation of elevated brain Cho is that it is a marker of neuroinflammation, and some evidence suggests that EtOH exposure promotes neuroinflammation. This study aimed to determine whether binge EtOH exposure (intragastric 3 g/kg 25% EtOH every 8 hours for 4 days) would induce the expression of certain cytokines in blood, liver, or brain, thereby supporting the neuroinflammation hypothesis of elevated Cho.

METHODS

Ten of 18 wild-type male Wistar rats (~322 g at baseline) were exposed to EtOH and attained average blood alcohol levels of ~315 mg/dl across 4 days. Blood for cytokine immunoassays was collected at baseline, after 5 doses of EtOH (binge), and immediately preceding euthanasia either 4 or 24 hours after the last dose of EtOH. Blood was additionally assayed for the levels of thiamine and liver enzymes; liver histopathology was performed postmortem; and tissue from liver and 6 brain regions was assayed for the potential induction of 7 cytokines.

RESULTS

There were no group effects on the levels of thiamine or its phosphate derivatives, thiamine monophosphate or thiamine diphosphate. ANOVAs of liver enzyme levels indicated that only alkaline phosphatase (ALP) levels were higher in the EtOH group than in control group at binge; ALP elevations, however, are difficult to explain in the absence of changes in the levels of additional liver enzymes. Postmortem liver pathology provided evidence for minimal microvesicular lipidosis and portocentric fibrosis in the EtOH group. Group effects on the levels of the measured cytokines in the blood (TNF-α, IFN-γ, IL-1β, IL-4, IL-5, IL-13, and GRO/CXCL1) were not significant. Similarly, postmortem evaluation of liver cytokines did not reveal group effects. Postmortem evaluation of the 7 cytokines in 6 brain regions (anterior cerebellar vermis, cingulate cortex, frontal cortex, hippocampus, hypothalamus, striatum) also failed to identify group effects.

CONCLUSIONS

A single 4-day bout of binge EtOH exposure alone was insufficient to induce the expression of 7 cytokines in blood, liver, or 6 brain regions of wild-type Wistar rats. Alternative interpretations for elevations in brain Cho in response to a 4-day binge EtOH treatment are therefore necessary and may include induction of cytokines not measured herein or other noninflammatory mechanisms.

Relative quantitative kinetics of interferon-gamma and interleukin-10 mRNA and protein production by activated ovine peripheral blood mononuclear cells

Interferon-gamma (IFN-gamma) and interleukin (IL)-10 are cross-regulatory cytokines capable of driving and controlling the adaptive host immune response. The inter-relationship between IFN-gamma and IL-10 expression has not been defined in sheep despite biological evidence suggesting that they perform similar functions to their orthologues described in other species. To address this, we have developed a quantitative (q)PCR method to assess relative levels of IFN-gamma and IL-10 mRNA expression in activated ovine peripheral blood mononuclear cells (PBMC) and compared the kinetics of mRNA expression with amounts of cytokine secreted by the cells over a 96h period. PBMC were collected from sheep immunised with the nominal antigen ovalbumin (Ova) and re-stimulated in vitro with antigen and the T cell mitogen concanavalin A (ConA). The recall response to antigen was characterised by a single peak in IFN-gamma mRNA expression at 48h of culture (13-fold increase over unstimulated cells) and relatively lower expression of IL-10 mRNA (average 2-3-fold increase over the 96h culture period). Antigen-driven IFN-gamma protein concentration was greatest at the end of the culture period (96h) whereas IL-10 protein level was not elevated above that observed in unstimulated cells. The typical response to ConA was greater for both cytokines, with IFN-gamma mRNA expression peaking at 6h of culture (133-fold increase) then declining rapidly whereas IL-10 mRNA expression peaked at 24h (16-fold increase) and declined more gradually. Despite these differences in the relative kinetics of mRNA expression in mitogen-activated PBMC, the typical pattern of protein expression of the two cytokines was similar. Both showed a gradual rise in protein concentration starting from 12h of culture which was still rising at the end of the culture period (96h). These data demonstrate that the kinetics of mRNA expression for IFN-gamma and IL-10 in activated ovine PBMC do not necessarily correlate with detectable protein in culture.

Relationship Between Periodontitis and Diabetes: Lessons From Rodent Studies

BACKGROUND

A great amount of investigations have provided evidence that both type 1 and type 2 diabetes increase the risk and severity of periodontitis; several alterations in the diabetic periodontium are likely to be involved. Conversely, periodontitis has been shown to have an impact on diabetes, although less evidence is available on the underlying mechanisms. The association between periodontitis and diabetes has been discussed in several reviews over the past years; however, none has focused on the use and contribution of rodent models.

METHODS

This review describes the most commonly used rodent models of diabetes, periodontitis, and the association between the two diseases. Further, we summarize the influence of diabetes in the periodontium as well as the effect of periodontitis on diabetes status with special focus on evidence from experimental studies.

RESULTS

Rodent studies have confirmed human findings and further increased our knowledge on the alterations in the diabetic periodontium. On the other hand, few rodent investigations have explored the consequences of periodontitis for diabetes. Their results clearly indicate that periodontitis can become a health hazard not only for diabetes but also for prediabetes; the exact mechanisms are still to be unraveled.

CONCLUSIONS

Findings from rodent studies have been useful in increasing our understanding of periodontitis, diabetes, and their association and hold great promise for future investigations given the wide variety of possibilities for testing biologic hypotheses.

Regulatory T-cell recovery in recipients of haploidentical nonmyeloablative hematopoietic cell transplantation with a humanized anti-CD2 mAb, MEDI-507, with or without fludarabine

OBJECTIVE

We have evaluated T-cell reconstitution and reactivity in patients receiving nonmyeloablative haploidentical hematopoietic cell transplantation (HCT) protocols involving an anti-CD2 monoclonal antibody (MEDI 507) to treat chemorefractory hematopoietic malignancies.

METHODS

Three cohorts of four patients each and one cohort of six patients received one of four Medi-507-based regimens, all of which included cyclophosphamide, thymic irradiation, and a short posttransplantation course of cyclosporine.

RESULTS

Following marked T-cell depletion, initially recovering CD4 and CD8 T cells were mainly memory-type cells. A high percentage of CD4 T cells expressed high levels of CD25 in recipients of all protocols, except the only protocol to include fludarabine, early post-HCT. CD25 expression varied inversely with T-cell concentrations in blood. CD25(high) CD4 T cells expressed Foxp3 and cytotoxic T-lymphocyte-associated protein 4, indicating that they were regulatory T cells (Treg).

CONCLUSIONS

Fludarabine treatment prevents Treg enrichment after haploidentical nonmyeloablative stem cell transplantation, presumably by depleting recipient Tregs. In vitro analyses of allorecognition were consistent with a cytokine-mediated rejection process in one case and in another provided proof of principle that mixed chimerism achieved without graft-vs-host disease induces donor- and recipient-specific tolerance. More reliable achievement of this outcome could provide a promising strategy for organ allograft tolerance induction.

Spontaneous inflammatory cytokine gene expression in normal human peripheral blood mononuclear cells

Cytokines regulate cellular immune activity and are produced by a variety of cells, especially lymphocytes, monocytes, and macrophages. Measurement of cytokine levels has yielded useful information on the pathological process of different diseases such as AIDS, endotoxic shock, sepsis, asthma, and cancer. It may also be of use in the monitoring of disease progression and/or inflammation. To determine spontaneous cytokine gene expression in whole blood and PBMCs, whole blood was obtained from healthy volunteers and total mRNA was isolated from PBMCs. The kinetics of response were determined by sequential testing of cytokine gene expression by RT-PCR analysis. Our results demonstrated that isolated and incubated PBMCs expressed TNF-alpha and high levels of IL-1beta, IL-6, IL-8, and IL-10. In contrast, WB only expressed the mRNA cytokines of TNF-alpha and IL-8 (p < 0.05). These results suggest that spontaneous myriad mRNA cytokine expression can be avoided with the use of WB incubation and the rapid collection of PBMCs. Furthermore, this method should be employed in all cases where the levels of cytokine gene expression can be evaluated.

Expression of a novel cytokine, IL-4delta2, in HIV and HIV-tuberculosis co-infection

BACKGROUND

Correcting the Th2 shift in HIV/AIDS represents a potential intervention strategy. However data on interleukin (IL)-4 expression in HIV or AIDS are un-interpretable because of failure to distinguish between IL-4 and its splice variant and natural antagonist, IL-4delta2.

OBJECTIVE

To determine Th1 [interferon (IFN)-gamma], IL-4delta2 and Th2 (IL-4) expression in whole blood and lung lavage from healthy volunteers and in HIV or HIV-tuberculosis (TB) co-infection.

DESIGN

Cross-sectional with prospective cohort.

METHODS

Expression of IL-4delta2, IL-4 and IFN-gamma were determined by quantitative real-time PCR, using unstimulated cells from whole blood and lung lavage, in 20 HIV-TB (pulmonary) co-infected patients, 20 matched HIV-positive controls and 20 HIV-negative healthy volunteers. Results were correlated with plasma viral load, CD4 cell counts, radiological scores and response to anti-TB treatment.

RESULTS

Compared to HIV negative donors, stable HIV-positive donors did not have increased levels of mRNA encoding IL-4, IL-4delta2 or IFN-gamma in blood or lavage. By contrast, the HIV-TB co-infected donors had increased IL-4 and IFN-gamma in both compartments. However the antagonist, IL-4delta2 was increased only in lavage. Consequently the dominant form was IL-4delta2 in lavage, but IL-4 itself in blood. The lung IL-4/IFN-gamma ratio correlated with radiological disease extent. With anti-TB treatment, IL-4 levels did not change whilst IL-4delta2 levels increased significantly.

CONCLUSIONS

IL-4 and its natural antagonist, IL-4delta2 and are not upregulated in the absence of opportunistic infection. However in HIV-TB co-infection both cytokines increase in lung, but only IL-4 in the periphery. Further studies are required to determine if IL-4 facilitates systemic HIV progression.

In VivoandIn VitroStudies of a Novel Cytokine, Interleukin 4δ2, in Pulmonary Tuberculosis

RATIONALE

Tuberculosis progresses despite potent Th1 responses. A putative explanation is the simultaneous presence of a subversive Th2 response. However, interpretation is confounded by interleukin 4delta2 (IL-4delta2), a splice variant and inhibitor of IL-4.

OBJECTIVE

To study levels of mRNA encoding IL-4 and IL-4delta2, and their relationship to treatment and clinical parameters, in cells from lung lavage and blood from patients with pulmonary tuberculosis.

METHODS

IL-4delta2, IFN-gamma, IL-4, and soluble CD30 (sCD30) levels were measured by polymerase chain reaction and relevant immunoassays in 29 patients and matched control subjects lacking responses to tuberculosis-specific antigens.

RESULTS

mRNA levels for IL-4 and IL-4delta2 were elevated in unstimulated cells from blood and lung lavage of patients versus control subjects (p < 0.005). In control subjects, there were low basal levels of IL-4 and IL-4delta2 mRNA expressed mainly by non-T cells (p < 0.05). However, in patients, there were greater levels of mRNA for both cytokines in both T- and non-T-cell populations (p < 0.05 compared with control subjects). Radiologic disease correlated with the IL-4/IFN-gamma ratio and sCD30 (p < 0.005). After chemotherapy, IL-4 mRNA levels remained unchanged, whereas IL-4delta2 increased in parallel with IFN-gamma (p < 0.05). Sonicates of Mycobacterium tuberculosis upregulated expression of IL-4 relative to IL-4delta2 in mononuclear cell cultures from patients (p < 0.05).

CONCLUSIONS

A Th2-like response, prominent in T cells and driven by tuberculosis antigen, is present in tuberculosis and modulated by treatment, suggesting a role for IL-4 and IL-4delta2 in the pathogenesis of tuberculosis and their ratio as a possible marker of disease activity. The specific antigens inducing the IL-4 response require identification to facilitate future vaccine development strategies.

Cytokine mRNA repertoire of peripheral blood mononuclear cells in Takayasu's arteritis

We have investigated constitutive and phytohaemagglutinin (PHA) + phorbol 12-myristate 13-acetate (PMA)-induced gene expression of tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-2, IL-3, IL-4, IL-10, IL-12 and granulocyte macrophage colony-stimulating factor (GM-CSF) in peripheral blood mononuclear cells (PBMCs) of 10 patients with Takayasu's arteritis (TA) and 10 healthy controls by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). The constitutive mRNA expression of TNF-alpha (69.0 +/- 4.0%versus 27.5 +/- 18.0%; P = 0.001) and IL-4 (60.0 +/- 10.0%versus 0%; P = 0.001) was significantly higher in patients than controls; that of IL-3 was comparable in both groups (38.0 +/- 6.0%versus 32.0 +/- 5.0%; P = 0.651) while no constitutive mRNA expression was observed for the other cytokines studied. The stimulated PBMCs of patients, as compared with the controls, had higher mRNA gene expression of TNF-alpha (127.0 +/- 16.0%versus 54.0 +/- 6.0%; P = 0.001), IFN-gamma (93.0 +/- 13.0%versus 57.0 +/- 5.0%; P = 0.032), IL-2 (109.0 +/- 13.0%versus 68.0 +/- 6.0%; P = 0.015), IL-3 (60.0 +/- 8.0%versus 21.2 +/- 3.0%; P = 0.045) and IL-4 (68.0 +/- 7.0%versus 27.0 +/- 7.2%; P = 0.01) The mRNA expression of IL-10 was lower in patients than controls (35.0 +/- 8.0%versus 75.0 +/- 12.0%; P = 0.022). The GM-CSF mRNA was similar (102.0 +/- 6.0%versus 89.0 +/- 5.0%; P = 0.475) in both groups. Stimulation of cells with PHA + PMA showed no IL-12 expression but stimulation with lipopolysaccharide induced higher IL-12 mRNA in patients than controls (83.0 +/- 14.0%versus 33.0 +/- 4.0%; P = 0.005). Our data suggest that an inflammatory cytokine signature exists in TA with a key role for TNF-alpha, IL-4, IL-10 and IL-12 in different pathological processes of the disease.

Interleukin-4 induced by measles virus and measles-derived peptides as measured by IL-4 receptor-blocking ELISA

Interleukin-4 (IL-4) is a signature cytokine for T-helper 2 (Th2) type immune responses in humans. However, data on antigen-specific secretion of IL-4 is limited due to difficulties detecting IL-4. We evaluated an IL-4 receptor-blocking assay for the detection of secreted IL-4 in peripheral blood mononuclear cells (PBMC) stimulated in vitro with measles virus (MV) and MV-derived nucleoprotein (N) and phosphoprotein (P) peptides. We recruited 20 healthy subjects, previously immunized with two doses of measles-mumps-rubella-II (MMR-II) vaccine. We evaluated the cellular and humoral immune status of these study subjects by an in vitro lymphoproliferation assay and an enzyme-linked immunosorbent assay (ELISA), respectively. We analyzed the MV-induced and N and P peptide-induced IL-4 levels in PBMC culture supernatants. Using the IL-4 receptor blocking assay, 50% of the subjects were positive for secreted IL-4 in response to MV stimulation, and 5% and 23.1% of study subjects were positive for secreted IL-4 in response to MV-derived N and P peptides, respectively. In contrast, we did not find any positive secreted IL-4 response to MV using conventional ELISA without IL-4 receptor-blocking antibody in our optimization study. Further, we found very low frequencies of IL-4 secreting cells using an alternate ELISpot technique, accounting for only a 5% positive response to MV and no response to P peptide. We propose that the IL-4 receptor-blocking assay is an easy-to-adapt technique for screening antigen-specific immune responses in large-scale population-based studies.

Kinetics of cytokine gene expression in human CD4+ and CD8+ T-lymphocyte subsets using quantitative real-time PCR

The time kinetics of five cytokines [interleukin-2 (IL-2), IL-5, interferon-gamma (IFN-gamma), granulocyte macrophage-colony stimulating factor (GM-CSF) and tumour necrosis factor-alpha (TNF-alpha)] and one cytotoxic effector protein (granzyme B) was analysed by real-time quantitative polymerase chain reaction (PCR) following in vitro stimulation of human CD4 and CD8 T lymphocytes. Two stimuli were used, a mitogen [phytohemagglutinin (PHA)] and a recall antigen [purified protein derivative (PPD)]. The pattern of cytokine mRNA expression was found to be dependent on the T-cell subset and stimulus used. A wide interindividual variability in the cytokine gene expression pattern was demonstrated. Two expression patterns were observed. A bell-shaped expression profile was seen for most cytokines upon PHA activation in both subsets and PPD-activated CD4 T cells, whereas a biphasic/multiphasic expression pattern was noted in CD8 T cells upon PPD stimulation. For most cytokines, the time to induction was within 30 min of activation, and maximum accumulation seemed to be obtained after 4-8 h of activation. A sustained high level could, however, be noticed for up to 24 h. Granzyme B gene expression was also induced within 30 min of activation but showed a continuous gradual increase and late maximal accumulation (48-72 h). The findings of the present study are of importance when designing studies using the cytokine gene expression profile as a marker for antigen-specific T lymphocytes. It might be recommended that cytokine gene expression (IL-2, IL-5 and IFN-gamma) should be measured after 4-8 h of specific activation but also up to 24 h of stimulation is acceptable. Granzyme B should preferentially be measured after 48-72 h of activation.

TH1 and TH2 cytokine mRNA and protein levels in human immunodeficiency virus (HIV)-seropositive and HIV-seronegative youths

The roles of cytokines in the progression of human immunodeficiency virus (HIV)-associated disease are controversial. The patterns of innate cytokine production have been postulated to shift from TH1- to TH2-type cytokines with the progression of HIV-associated disease. Although there have been studies of cytokines in children and adults, no data are available on cytokine production in healthy or HIV-infected adolescents. We analyzed and characterized cytokine mRNA and protein levels for gamma interferon, interleukin 2 (IL-2), IL-4, and tumor necrosis factor alpha and protein levels of IL-6 in both stimulated and unstimulated peripheral blood mononuclear cells obtained from a large longitudinal, observational cohort study of HIV-seropositive and -seronegative adolescents. We correlated cytokine results with viral load and CD4(+)-T-cell counts as critical markers of disease progression in HIV-infected adolescents. These data were used to examine hypotheses related to the TH1-to-TH2 cytokine shift in a sample of HIV-infected adolescents. Five hundred twenty subjects participating in the REACH (Reaching for Excellence in Adolescent Care and Health) Project of the Adolescent Medicine HIV/AIDS Research Network contributed blood samples. Samples selected for the cross-sectional data set analyzed had to meet selection criteria developed to minimize the potential confounding effects of acute intercurrent illnesses or infections, recent vaccination for hepatitis, and altered hormone status and to optimize congruence of cytokine measurements with assays of viral load and CD4(+)-T-cell counts. Group differences in the proportions of subjects with detectable levels of each cytokine marker were compared. In the subset of subjects with detectable cytokine values, differences in detected values were compared across subgroups defined by HIV serostatus and among HIV-seropositive subjects by three viral load classifications. The study sample was 65% HIV seropositive, 71% African-American, and 75% female with a mean age of 17.4 years. HIV-seropositive subjects were relatively healthy with mean and median CD4(+)-T-cell counts of 534 and 499 cells/mm(3), respectively. Only 8.1% of subjects had CD4(+)-T-cell counts below 200 cells/mm(3), and 25% had viral loads that were below the threshold of detection (<400 copies/ml). Detailed analyses of these data indicate that there were no differences in cytokines detected in HIV-seropositive and HIV-seronegative adolescents, and there was no apparent relationship between the cytokine measurements and the viral load or CD4(+)-T-cell categorization, the parameters selected as markers of HIV-associated disease status. These adolescents, including the HIV-seropositive subjects, were relatively healthy, and the HIV-infected subjects were at an early stage in the course of their HIV-associated disease. On the basis of our data, we conclude that, early in the course of HIV-associated disease in adolescents, there are no detectable shifts from TH1 to TH2 cytokine production.

Enhanced monocyte Th1 cytokine production in HCV-infected cryoglobulinemic patients

BACKGROUND/AIMS

The etiologic link between chronic hepatitis C virus (HCV) infection and mixed cryoglobulinemia is well established, while its prognostic significance within the context of HCV-related hepatitis is not as clear. Patients with an HCV-related cryoglobulinemic syndrome oft have mild liver disease, an aspect that can be influenced by an individual's Th1/Th2 orientation. Our goal was to document stigmata of differentiate cytokine production in this subgroup of patients.

METHODS

Fifteen patients with chronic HCV-related liver disease (CLD) and a cryoglobulinemic syndrome (CRYO) were compared to age/sex matched CLD controls with negative cryocrit. Cultured monocytes were stimulated with either Staphylococcus aureus (SAC) or lipopolysaccharide (LPS).

RESULTS

The protein concentrations of TNF-alpha and of the Th1-type cytokines interleukin (IL)-12 and IL-18 were significantly greater in the CRYO group, while IL-10 (a Th2 cytokine) levels were greater in the control group.

CONCLUSIONS

The clinical distinctiveness of the two groups was reflected at the cytokine level. The cryoglobulinemic patients studied showed a greater Th1 polarization than their cryoglobulin-negative counterparts. This enhanced production of Th1-type cytokines is seemingly not able to rid the host of infection but may account for a milder course of liver disease.

In vitro effects of monophthalates on cytokine expression in the monocytic cell line THP-1 and in peripheral blood mononuclear cells from allergic and non-allergic donors

It has recently been shown that plasticizers are present in indoor air dust, which may lead to human exposure via the inhalation route. Moreover, studies have indicated that plasticizers may possess adjuvant effects increasing the health damaging potential of allergens. The aim of this study was to investigate the in vitro effect of metabolites of phthalate plastisizers, such as whether an adjuvant effect is paralleled by changes of the cytokine expression in the monocytic cell line THP-1 and in peripheral blood mononuclear cells (PBMCs) from allergics and non-allergics. The toxicity monitored by cell viability was determined by incubating THP-1 cells with a 10-fold dilution series of monophthalates for 24 h. At different points in time cytokine expression (IL-1beta, IL-6, IL-12alpha (p35)) in THP-1 cells incubated with non-toxic concentrations of monophthalate (2-20 microg/ml)+/-LPS (1 microg/ml) were determined using Quantitative Competitive RT-PCR. PBMCs from allergics and non-allergics were incubated with monophthalate 220 microg/ml) for up to 48 h and cytokine expression (IL-4, IL-5, IFN-gamma) was measured using real-time PCR. The cytotoxic level of monophthalates is 20-200 microg/ml, depending on the individual monophthalate. There seems to be a correlation between increasing side-chain length and toxicity. Monophthalates did not induce changes in cytokine expression in THP-1 cells, though there is an increase when co-incubating with LPS. Cytokine expression in PBMC seems virtually unchanged when co-incubated with monophthalate, though mono-n-butyl phthalate (MBUP) tends to increase the level of IL-4 in PBMCs from allergic individuals. The two cellular models demonstrated the dynamics of regulated cytokine mRNA and are applicable for in vitro immunotoxicological investigations. The results regarding monophthalates suggest these to have a limited effect on cytokine expression in the monocytic cell line THP-1 and weak effect on cytokine expression in PBMCs from allergic and non-allergic individuals.

Up-regulation by feline interleukin-4 and down-regulation by feline interferon-gamma of major histocompatibility complex class II on cat B-lymphocytes

Interleukin-4 (IL-4) exhibits numerous biological and immunoregulatory functions on B- and T-lymphocytes, monocytes, and dendritic cells in both mice and humans. In the present study, we show that IL-4 also has a regulatory function in the cat species. Cells transfected with IL-4 DNA expressed a biologically active protein as demonstrated by the up-regulation of MHC class II molecules on B-lymphocytes (CD21(+)) in a flow cytometric assay. Increased levels of MHC class II expression on CD21(+) cells were seen in 11 out of 12 cats (p<0.05). In addition, 12 out of 12 cats showed up-regulation of MHC class II on CD21(-) cells, mainly consisting of T-lymphocytes (p<0.05). In contrast, concanavalin A (ConA)-induced culture supernatant from peripheral blood mononuclear cells (PBMCs) containing high levels of interferon-gamma (IFN-gamma) transcripts induced down-regulation of MHC class II molecules on CD21(+) cells of all samples (p<0.05). Variable results were observed for CD21(-) cells incubated with ConA-conditioned medium (p=0.71). The nature of the cytokine(s) responsible for these effects remains to be determined. However, the fact that down-regulation of MHC class II molecules on B cells occurred in all cats tested suggests that IFN-gamma may be involved. These data provide further insight into the mechanism by which MHC class II expression is regulated in feline lymphocytes, and suggest that the Th1/Th2 paradigm is also present in the cat.

Spontaneous cytokine production and its effect on induced production

Cytokines regulate cellular immune activity and are produced by a variety of cells, especially lymphocytes, monocytes, and macrophages. Multiparameter flow cytometry is often used to examine cell-specific cytokine production after in vitro phorbol 12-myristate 13-acetate and ionomycin induction, with brefeldin A or other agents added to inhibit protein secretion. Spontaneous ex vivo production reportedly rarely occurs. We examined the spontaneous production of interleukin 2 (IL-2), IL-4, IL-6, IL-8, IL-10, tumor necrosis factor alpha (TNF-alpha), and gamma interferon (IFN-gamma) by peripheral-blood B lymphocytes, T cells, CD8(-) T cells, CD8(+) T cells, CD3(-) CD16/56(+) lymphocytes (natural killer [NK] cells), CD3(+) CD16/56(+) lymphocytes (natural T [NT] cells), and/or monocytes of 316 acutely ill hospitalized persons and 62 healthy adults in Malawi, Africa. We also evaluated the relationship between spontaneous and induced cytokine production. In patients, spontaneous TNF-alpha production occurred most frequently, followed in descending order by IFN-gamma, IL-8, IL-4, IL-10, IL-6, and IL-2. Various cells of 60 patients spontaneously produced TNF-alpha; for 12 of these patients, TNF-alpha was the only cytokine produced spontaneously. Spontaneous cytokine production was most frequent in the immunoregulatory cells, NK and NT. For IL-2, IL-4, IL-6, IL-8, and IL-10, spontaneous cytokine production was associated with greater induced production. For TNF-alpha and IFN-gamma, the relationships varied by cell type. For healthy adults, IL-6 was the cytokine most often produced spontaneously. Spontaneous cytokine production was not unusual in these acutely ill and healthy persons living in an area where human immunodeficiency virus, mycobacterial, malaria, and assorted parasitic infections are endemic. In such populations, spontaneous, as well as induced, cell-specific cytokine production should be measured and evaluated in relation to various disease states.

Expandability of haemopoietic progenitors in first trimester fetal and maternal blood: implications for non-invasive prenatal diagnosis

OBJECTIVES

Selective amplification of rare fetal cells in maternal blood is a potential strategy for non-invasive prenatal diagnosis. We assessed the proliferative potential of first trimester fetal progenitors compared to maternal ones.

METHODS

Fetal and maternal haemopoietic progenitors were cultured separately and in two model mixtures: (i) co-cultures of male fetal nucleated cells mixed with maternal nucleated cells and (ii) co-cultures of malefetal CD34+ cells with maternal CD34+ cells. Cell origin was detected by X-Y fluorescence in situ hybridisation (FISH) RESULTS: The frequency of haemopoietic progenitors in first trimester fetal blood (predominantly CFU-GEMM) differed from those in peripheral blood from pregnant women (predominantly BFU-e). First trimester haemopoietic progenitors formed larger colonies (p=0.0001) and their haemoglobinisation was accelerated compared to those of maternal origin (p<0.001). CD34+ fetal haemopoietic progenitor cells could be expanded four times more than their maternal counterparts (median 235.8-fold, range 174.0-968.0 vs 71.9-fold, range 41.1-192.0; p=0.003). While selective expansion of fetal cells was not observed in the mononuclear cell model, the CD34+ cell rare event mixtures produced a 463.2-fold (range 128.0-2915.0) expansion of fetal cells.

CONCLUSION

Selective expansion of first trimester fetal haemopoietic progenitors may be useful for amplifying fetal cells from maternal blood.