Cytokine gene expression in normal human lymphocytes in response to stimulation

The transcriptomic signature of respiratory sensitizers using an alveolar model

Environmental contaminants are ubiquitous in the air we breathe and can potentially cause adverse immunological outcomes such as respiratory sensitization, a type of immune-driven allergic response in the lungs. Wood dust, latex, pet dander, oils, fragrances, paints, and glues have all been implicated as possible respiratory sensitizers. With the increased incidence of exposure to chemical mixtures and the rapid production of novel materials, it is paramount that testing regimes accounting for sensitization are incorporated into development cycles. However, no validated assay exists that is universally accepted to measure a substance's respiratory sensitizing potential. The lungs comprise various cell types and regions where sensitization can occur, with the gas-exchange interface being especially important due to implications for overall lung function. As such, an assay that can mimic the alveolar compartment and assess sensitization would be an important advance for inhalation toxicology. Some such models are under development, but in-depth transcriptomic analyses have yet to be reported. Understanding the transcriptome after sensitizer exposure would greatly advance hazard assessment and sustainability. We tested two known sensitizers (i.e., isophorone diisocyanate and ethylenediamine) and two known non-sensitizers (i.e., chlorobenzene and dimethylformamide). RNA sequencing was performed in our in vitro alveolar model, consisting of a 3D co-culture of epithelial, macrophage, and dendritic cells. Sensitizers were readily distinguishable from non-sensitizers by principal component analysis. However, few differentially regulated genes were common across all pair-wise comparisons (i.e., upregulation of genes SOX9, UACA, CCDC88A, FOSL1, KIF20B). While the model utilized in this study can differentiate the sensitizers from the non-sensitizers tested, further studies will be required to robustly identify critical pathways inducing respiratory sensitization.

Single-cell deep phenotyping of cytokine release unmasks stimulation-specific biological signatures and distinct secretion dynamics

Cytokines are important mediators of the immune system, and their secretion level needs to be carefully regulated, as an unbalanced activity may lead to cytokine release syndromes. Dysregulation can be induced by various factors, including immunotherapies. Therefore, the need for risk assessment during drug development has led to the introduction of cytokine release assays (CRAs). However, the current CRAs offer little insight into the heterogeneous cellular dynamics. To overcome this limitation, we developed an advanced single-cell microfluidic-based cytokine secretion platform to quantify cytokine secretion on the single-cell level dynamically. Our approach identified different dynamics, quantities, and phenotypically distinct subpopulations for each measured cytokine upon stimulation. Most interestingly, early measurements after only 1 h of stimulation revealed distinct stimulation-dependent secretion dynamics and cytokine signatures. With increased sensitivity and dynamic resolution, our platform provided insights into the secretion behavior of individual immune cells, adding crucial additional information about biological stimulation pathways to traditional CRAs.

Stimulation of alpha-1 adrenoceptors may intensify cutaneous inflammation in complex regional pain syndrome

ABSTRACT

Alpha-1 adrenoceptors are overexpressed in the epidermis of a subgroup of patients with complex regional pain syndrome (CRPS). Activating α 1 -adrenoceptors in epidermal cells increases production of the proinflammatory cytokine interleukin-6 (IL-6), a mediator of inflammation. To investigate whether this might exacerbate inflammation in CRPS, primary keratinocytes or dermal fibroblasts were cultured from skin biopsies obtained from the affected limb of 25 patients and a similar site in 28 controls. The fundamental proinflammatory cytokine, tumor necrosis factor alpha, was administered for 24 hours to initiate inflammation. After this, cells were incubated for 6 hours with the α 1 -adrenoceptor agonist phenylephrine. Exposure to tumor necrosis factor alpha induced proinflammatory cytokine mRNA production and protein secretion in keratinocytes and fibroblasts and enhanced α 1B -adrenoceptor mRNA expression in keratinocytes. Additional stimulation of α 1 adrenoceptors with phenylephrine increased the production of IL-6 mRNA and protein secretion in both cell types. Under all conditions, gene and protein α 1 -adrenoceptor levels and cytokine gene expression and protein secretion were similar, overall, in patients and controls, except for abnormally high α 1 -adrenoceptor protein levels in the keratinocytes of 3 of 17 patients. These findings suggest that persistent inflammation in CRPS is not due to dysfunction of skin cells but is a normal response to extrinsic signals. After α 1 -adrenoceptor stimulation of keratinocytes, increases in IL-6 mRNA but not protein were proportional to basal α 1 -adrenoceptor protein levels. Skin cells play an important role in persistent inflammation in CRPS. Potentially, a positive feedback loop between α 1 -adrenoceptors and IL-6 production in skin cells contributes to this inflammatory state.

Intracellular inflammatory signalling cascades in human monocytic cells on challenge with phytohemagglutinin and 2,4,6-trinitrophenol

Phytohemagglutinin (PHA) is a plant mitogen that can agglutinate human leukocytes and erythrocytes. PHA is mainly derived from red kidney beans and can act as an exogenous pyrogen. When entering into the blood circulation, exogenous pyrogens principally interact with monocytes and macrophages and induce the release of pro-inflammatory cytokines. Monocytes and macrophages are the cells that fight against foreign invaders and acts as a primary line of immune defence. Similar to PHA, the chemical 2,4,6-trinitrophenol (TNP) also acts as an exogenous pyrogen. The study focused on the in vitro interaction of PHA and TNP with the human monocyte/macrophage cell model THP-1. The exposure and associated change in cellular morphology, organelle function, mechanism of cell death, inflammatory signalling and expression of inflammation-related genes were analyzed in different time periods. It was observed that PHA and TNP induce dose and time-dependent toxicity to monocytes/macrophages where the mechanism of cell death was different for PHA and TNP. Both PHA and TNP can evoke immune signalling with increased expression of inflammatory genes and associated activation of intracellular signalling cascades.

Chemokine-like factor-like MARVEL transmembrane domain-containing family in autoimmune diseases

The chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is widely expressed in the immune system. Abnormal expression of CMTM is associated with the development of various diseases. This article summarizes the relevant research on the role of the CMTM family in immune disorders. This information will increase our understanding of pathogenesis and identify promising targets for the diagnosis and treatment of autoimmune diseases. The CMTM family is highly expressed in peripheral blood mononuclear cells. CKLF1 may be involved in the development of arthritis through its interaction with C-C chemokine receptor 4. CKLF1 is associated with the pathogenesis of lupus nephritis and psoriasis. Both CMTM4 and CMTM5 are associated with the pathogenesis of systemic lupus erythematosus. CMTM1, CMTM2, CMTM3, and CMTM6 play a role in rheumatoid arthritis, systemic sclerosis, Sjögren syndrome, and anti-phospholipid syndrome, respectively. The CMTM family has been implicated in various autoimmune diseases. Further research on the mechanism of the action of CMTM family members may lead to the development of new treatment strategies for autoimmune diseases.

Cyclopenta[b]indole Derivative Inhibits Aurora B in Primary Cells

The Aurora family of kinases is closely involved in regulating cell division. Inhibition of Aurora A and B with small molecules is currently being investigated in clinical trials for the treatment of different cancers. It has also been evaluated as a treatment option against different autoimmune diseases in preclinical studies. Here, we present a cyclopenta[b]indole derivative capable of inhibiting Aurora B selectively in kinase assays. To evaluate the Aurora B inhibition capacity of the compound, we used a kinase IC₅₀ assay as well as a suppression assay of proliferating primary cells. In addition, we examined if the cells had gained a phenotype characteristic for Aurora B inhibition after treatment with the compound. We found that the compound selectively inhibited Aurora B (IC₅₀ = 1.4 μM) over Aurora A (IC₅₀ > 30 μM). Moreover, the compound inhibited proliferating PBMCs with an IC₅₀ = 4.2 μM, and the cells displayed reduced phosphorylation of histone H3 as well as tetraploidy, consistent with Aurora B inhibition.

Immune responses to HIV-1 polytope vaccine candidate formulated in aqueous and alcoholic extracts of Propolis: Comparable immune responses to Alum and Freund adjuvants

Today's, vaccination is the most cost-effective approaches for preventing infectious diseases. In this strategy, adjuvants play an important role. Propolis from honey bee can stimulate the immune system and several studies have shown the modulating effects of Propolis on the immune responses. Here, the adjuvant effects of aqueous and alcoholic extracts of Propolis were studied on the multi-epitope vaccines against HIV-1. A recombinant vaccine against HIV-1 was prepared and BALB/c mice were immunized. subcutaneously on day 0 with 100 μl of candidate vaccine (10 μg) formulated in an alcoholic extract of Propolis. The second group of mice was immunized with the vaccine (10 μg) formulated in aqueous extract of Propolis. Also, candidate vaccine was formulated in Freund's and Alum adjuvants in the third and fourth groups. Experimental mice were immunized three times with two week intervals under the same conditions and suitable control groups. After final injection, lymphocyte proliferation was measured by BrdU method, IL-4 and IFN-γ cytokines, specific total IgG antibodies, IgG1 and IgG2a isotypes were evaluated using ELISA. The results show that the aqueous and alcoholic extracts were able to enhance lymphocyte proliferation, IL-4 and IFN-γ cytokines and antibody responses with dominant IgG1 pattern and comparable to Freund's and Alum adjuvants. It seems that aqueous and alcoholic extracts of Propolis show adjuvant activity and may be useful for vaccine formulation.

Immune response of hibernating European bats to a fungal challenge

Immunological responses of hibernating mammals are suppressed at low body temperatures, a possible explanation for the devastating effect of the white-nose syndrome on hibernating North American bats. However, European bats seem to cope well with the fungal causative agent of the disease. To better understand the immune response of hibernating bats, especially against fungal pathogens, we challenged European greater mouse-eared bats (Myotis myotis) by inoculating the fungal antigen zymosan. We monitored torpor patterns, immune gene expressions, different aspects of the acute phase response and plasma oxidative status markers, and compared them with sham-injected control animals at 30 min, 48 h and 96 h after inoculation. Torpor patterns, body temperatures, body masses, white blood cell counts, expression of immune genes, reactive oxygen metabolites and non-enzymatic antioxidant capacity did not differ between groups during the experiment. However, zymosan injected bats had significantly higher levels of haptoglobin than the control animals. Our results indicate that hibernating greater mouse-eared bats mount an inflammatory response to a fungal challenge, with only mild to negligible consequences for the energy budget of hibernation. Our study gives a first hint that hibernating European bats may have evolved a hibernation-adjusted immune response in order to balance the trade-off between competent pathogen elimination and a prudent energy-saving regime.

Summary: Our experimental immunological study on European bats provides new information on the functionality of the immune system in hibernation. For this we challenged bats with a fungal antigen and measured different immunological parameters.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.

Cannabinoid Receptor 2 (CB2) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes

Cannabinoid receptor 2 (CB₂) is a promising therapeutic target for immunological modulation. There is, however, a deficit of knowledge regarding CB₂ signaling and function in human primary immunocompetent cells. We applied an experimental paradigm which closely models the in situ state of human primary leukocytes (PBMC; peripheral blood mononuclear cells) to characterize activation of a number of signaling pathways in response to a CB₂-selective ligand (HU308). We observed a "lag" phase of unchanged cAMP concentration prior to development of classically expected Gα_i-mediated inhibition of cAMP synthesis. Application of G protein inhibitors revealed that this apparent lag was a result of counteraction of Gα_i effects by concurrent Gα_s activation. Monitoring downstream signaling events showed that activation of p38 was mediated by Gα_i, whereas ERK1/2 and Akt phosphorylation were mediated by Gα_i-coupled βγ. Activation of CREB integrated multiple components; Gα_s and βγ mediated ∼85% of the response, while ∼15% was attributed to Gα_i. Responses to HU308 had an important functional outcome-secretion of interleukins 6 (IL-6) and 10 (IL-10). IL-2, IL-4, IL-12, IL-13, IL-17A, MIP-1α, and TNF-α were unaffected. IL-6/IL-10 induction had a similar G protein coupling profile to CREB activation. All response potencies were consistent with that expected for HU308 acting via CB₂. Additionally, signaling and functional effects were completely blocked by a CB₂-selective inverse agonist, giving additional evidence for CB₂ involvement. This work expands the current paradigm regarding cannabinoid immunomodulation and reinforces the potential utility of CB₂ ligands as immunomodulatory therapeutics.

Immuno-Modulatory and Anti-Inflammatory Effects of Dihydrogracilin A, a Terpene Derived from the Marine Sponge Dendrilla membranosa

We assessed the immunomodulatory and anti-inflammatory effects of 9,11-dihydrogracilin A (DHG), a molecule derived from the Antarctic marine sponge Dendrilla membranosa. We used in vitro and in vivo approaches to establish DHG properties. Human peripheral blood mononuclear cells (PBMC) and human keratinocytes cell line (HaCaT cells) were used as in vitro system, whereas a model of murine cutaneous irritation was adopted for in vivo studies. We observed that DHG reduces dose dependently the proliferative response and viability of mitogen stimulated PBMC. In addition, DHG induces apoptosis as revealed by AnnexinV staining and downregulates the phosphorylation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), signal transducer and activator of transcription (STAT) and extracellular signal–regulated kinase (ERK) at late time points. These effects were accompanied by down-regulation of interleukin 6 (IL-6) production, slight decrease of IL-10 and no inhibition of tumor necrosis factor-alpha (TNF-α) secretion. To assess potential properties of DHG in epidermal inflammation we used HaCaT cells; this compound reduces cell growth, viability and migration. Finally, we adopted for the in vivo study the croton oil-induced ear dermatitis murine model of inflammation. Of note, topical use of DHG significantly decreased mouse ear edema. These results suggest that DHG exerts anti-inflammatory effects and its anti-edema activity in vivo strongly supports its potential therapeutic application in inflammatory cutaneous diseases.

Dynamics of cytokine gene expression in peripheral blood mononuclear cells of indigenous and exotic breeds of pigs in India

To incorporate immune competence traits in swine breeding programs, association between immune responsiveness and susceptibility to specific infectious diseases must be established. In order to understand the differences in immune competence between indigenous (Zovawk) and exotic (Large White Yorkshire: LWY) pigs reared in India, we carried out a time course expression analysis of immune-regulating key cytokine genes (interleukin (IL)-2, interferon (IFN)-γ, IL-4 and IL-10) in the phytohemagglutinin-P stimulated peripheral blood mononuclear cells (PBMCs). The IL-2 transcript levels in PBMCs increased several thousand-fold when compared to unstimulated cells in both the breeds, albeit the response in that of Zovawk was remarkably higher. Higher and earlier IFN-γ and IL-4 expression levels in Zovawk pigs suggest that both T_H 1 and T_H 2 immune responsiveness of this indigenous breed affords better preparedness for danger signals. Moreover, the low expression levels of IL-10 depict a regulated adaptive immune responsiveness. Remarkable difference between the two breeds of the pigs is evident showing a clear advantage of the Zovawk over LWY in terms of a shorter lag period of adaptive immune response. These findings provide a lead for understanding the genetic differences with respect to immune competence levels of indigenous pigs compared to exotic counterparts.

Capparis Spinosa L. promotes anti-inflammatory response in vitro through the control of cytokine gene expression in human peripheral blood mononuclear cells

BACKGROUND

Capparis Spinosa L. is an aromatic plant growing wild in dry regions around the Mediterranean basin. Capparis Spinosa was shown to possess several properties such as antioxidant, antifungal, and anti-hepatotoxic actions. In this work, we aimed to evaluate immunomodulatory properties of Capparis Spinosa leaf extracts in vitro on human peripheral blood mononuclear cells (PBMCs) from healthy individuals.

RESULTS

Using MTT assay, we identified a range of Capparis Spinosa doses, which were not toxic. Unexpectedly, we found out that Capparis Spinosa aqueous fraction exhibited an increase in cell metabolic activity, even though similar doses did not affect cell proliferation as shown by CFSE. Interestingly, Capparis Spinosa aqueous fraction appeared to induce an overall anti-inflammatory response through significant inhibition of IL-17 and induction of IL-4 gene expression when PBMCs were treated with the non toxic doses of 100 and/or 500 μg/ml. Phytoscreening analysis of the used Capparis Spinosa preparations showed that these contain tannins; sterols, alkaloids; polyphenols and flavonoids. Surprisingly, quantification assays showed that our Capparis Spinosa preparation contains low amounts of polyphenols relative to Capparis Spinosa used in other studies. This Capparis Spinosa also appeared to act as a weaker scavenging free radical agent as evidenced by DPPH radical scavenging test. Finally, polyphenolic compounds including catechin, caffeic acid, syringic acid, rutin and ferulic acid were identified by HPLC, in the Capparis spinosa preparation.

CONCLUSION

Altogether, these findings suggest that our Capparis Spinosa preparation contains interesting compounds, which could be used to suppress IL-17 and to enhance IL-4 gene expression in certain inflammatory situations. Other studies are underway in order to identify the compound(s) underlying this effect.

Electro-Magnetic Nano-Particle Bound Beclin1 siRNA Crosses the Blood-Brain Barrier to Attenuate the Inflammatory Effects of HIV-1 Infection in Vitro

The purpose of this study was to evaluate a novel drug delivery system comprised of ferric-cobalt electro-magnetic nano-material (CoFe2O4@ BaTiO3; MENP) bound to siRNA targeting Beclin1 (MENP-siBeclin1) to cross the blood-brain barrier (BBB) and attenuate the neurotoxic effects of HIV-1 infection in the central nervous system following on-demand release of siRNA using an in vitro primary human BBB model. Beclin1 is a key protein in the regulation of the autophagy pathway and we have recently demonstrated the importance of Beclin1 in regulating viral replication and viral-induced inflammation in HIV-1-infected microglia. The MENP-siBeclin1 nano-formulation did not compromise the physiological function or integrity of the BBB model. Furthermore, the in vitro BBB data revealed that MENP-siBeclin1 could efficiently attenuate viral replication and viral-induced inflammation, likely due to STAT1/ NF-κB signaling pathways. MENP-siBeclin1 also silenced Beclin1 protein expression in HIV-1-infected microglial cells within the model system. In addition, the cytotoxic effects of direct treatment with siBeclin1 and MENP alone or in nano-formulation on primary human neuronal cells showed a minimal amount of cell death. Overall, the data shows that the nano-formulation can silence the BECN1 gene as an effective mechanism to attenuate HIV-1 replication and viral-induced inflammation in the context of the BBB.

Inhibition of G-Protein βγ Signaling Decreases Levels of Messenger RNAs Encoding Proinflammatory Cytokines in T Cell Receptor-Stimulated CD4(+) T Helper Cells

Background: Inhibition of G-protein βγ (Gβγ) signaling was found previously to enhance T cell receptor (TCR)-stimulated increases in interleukin 2 (IL-2) mRNA in CD4⁺ T helper cells, suggesting that Gβγ might be a useful drug target for treating autoimmune diseases, as low dose IL-2 therapy can suppress autoimmune responses. Because IL-2 may counteract autoimmunity in part by shifting CD4⁺ T helper cells away from the Type 1 T helper cell (TH1) and TH17 subtypes towards the TH2 subtype, the purpose of this study was to determine if blocking Gβγ signaling affected the balance of TH1, TH17, and TH2 cytokine mRNAs produced by CD4⁺ T helper cells.

Methods: Gallein, a small molecule inhibitor of Gβγ, and siRNA-mediated silencing of the G-protein β₁ subunit (Gβ₁) were used to test the effect of blocking Gβγ on mRNA levels of cytokines in primary human TCR-stimulated CD4⁺ T helper cells.

Results: Gallein and Gβ₁ siRNA decreased interferon-γ (IFN-γ) and IL-17A mRNA levels in TCR-stimulated CD4⁺ T cells grown under TH1-promoting conditions. Inhibiting Gβγ also decreased mRNA levels of STAT4, which plays a positive role in TH1 differentiation and IL-17A production. Moreover, mRNA levels of the STAT4-regulated TH1-associated proteins, IL-18 receptor β chain (IL-18Rβ), mitogen-activated protein kinase kinase kinase 8 (MAP3K8), lymphocyte activation gene 3 (LAG-3), natural killer cell group 7 sequence (NKG7), and oncostatin M (OSM) were also decreased upon Gβγ inhibition. Gallein also increased IL-4, IL-5, IL-9, and IL-13 mRNA levels in TCR-stimulated memory CD4⁺ T cells grown in TH2-promoting conditions.

Conclusions: Inhibiting Gβγ to produce these shifts in cytokine mRNA production might be beneficial for patients with autoimmune diseases such as rheumatoid arthritis (RA), Crohn’s disease (CD), psoriasis, multiple sclerosis (MS), and Hashimoto’s thyroiditis (HT), in which both IFN-γ and IL-17A are elevated.

Cloning of interleukin-10 from African clawed frog (Xenopus tropicalis), with the Finding of IL-19/20 homologue in the IL-10 locus

Interleukin-10 (IL-10) is a pleiotropic cytokine that plays an important role in immune system. In the present study, the IL-10 gene of African clawed frog (Xenopus tropicalis) was first cloned, and its expression pattern and 3D structure were also analyzed. The frog IL-10 mRNA encoded 172 amino acids which possessed several conserved features found in IL-10s from other species, including five-exon/four-intron genomic structure, conserved four cysteine residues, IL-10 family motif, and six α-helices. Real-time PCR showed that frog IL-10 mRNA was ubiquitous expressed in all examined tissues, highly in some immune related tissues including kidney, spleen, and intestine and lowly in heart, stomach, and liver. The frog IL-10 mRNA was upregulated at 24 h after LPS stimulation, indicating that it plays a part in the host immune response to bacterial infection. Another IL, termed as IL-20, was identified from the frog IL-10 locus, which might be the homologue of mammalian IL-19/20 according to the analysis results of the phylogenetic tree and the sequence identities.

Inhibition of G-protein βγ signaling enhances T cell receptor-stimulated interleukin 2 transcription in CD4+ T helper cells

G-protein-coupled receptor (GPCR) signaling modulates the expression of cytokines that are drug targets for immune disorders. However, although GPCRs are common targets for other diseases, there are few GPCR-based pharmaceuticals for inflammation. The purpose of this study was to determine whether targeting G-protein βγ (Gβγ) complexes could provide a useful new approach for modulating interleukin 2 (IL-2) levels in CD4⁺ T helper cells. Gallein, a small molecule inhibitor of Gβγ, increased levels of T cell receptor (TCR)-stimulated IL-2 mRNA in primary human naïve and memory CD4⁺ T helper cells and in Jurkat human CD4⁺ leukemia T cells. Gβ₁ and Gβ₂ mRNA accounted for >99% of Gβ mRNA, and small interfering RNA (siRNA)-mediated silencing of Gβ₁ but not Gβ₂ enhanced TCR-stimulated IL-2 mRNA increases. Blocking Gβγ enhanced TCR-stimulated increases in IL-2 transcription without affecting IL-2 mRNA stability. Blocking Gβγ also enhanced TCR-stimulated increases in nuclear localization of nuclear factor of activated T cells 1 (NFAT1), NFAT transcriptional activity, and levels of intracellular Ca²⁺. Potentiation of IL-2 transcription required continuous Gβγ inhibition during at least two days of TCR stimulation, suggesting that induction or repression of additional signaling proteins during T cell activation and differentiation might be involved. The potentiation of TCR-stimulated IL-2 transcription that results from blocking Gβγ in CD4⁺ T helper cells could have applications for autoimmune diseases.

Detection of expression of IL-18 and its binding protein in Egyptian pediatric immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder, characterized by dysfunctional cellular immunity including the presence of activated platelet specific autoreactive T cells that recognize and respond to autologous platelet antigens. Autoreactive T cells drive the generation of platelet reactive autoantibodies by B cells as well as T-cytotoxic cell-mediated lysis of platelets. Interleukin-18 (IL-18) is a mediator of T helper type 1 cell responses synergistically with IL-12 that initiate and promote host defense and inflammation. IL-18 has a specific binding protein (IL-18BP) which belongs to the immunoglobulin superfamily. In the present study, serum level and messenger RNA( mRNA) expression of IL-18 as well as IL-18BP mRNA expression were measured in peripheral blood mononuclear cells (PBMNCs) of 100 Egyptian pediatric patients with ITP (70 acute and 30 chronic). In addition to this, we recruited 80 healthy volunteers in order to investigate the possible association between the imbalance of IL-18 and IL-18 BP expressions and the pathogenesis of ITP. IL-18 serum level and mRNA expression were not elevated in cases more than in the control group, but IL-18 mRNA was higher in chronic cases when compared to the acute ones (p=0.031) and there was a good negative correlation between the platelet count and serum IL-18. IL-18 BP m-RNA was slightly elevated in cases more than in the control group (95% Confidence interval=1.15-2.01). Our results were not supportive for previous findings of elevated IL18/BP mRNA ratio in ITP patients. This could be referred to the fact that autoimmune diseases are complex genetic disorders, therefore further studies on polymorphisms affecting IL-18 gene expression as well as kinetics of IL-18 expression are required to evaluate the role of interleukin 18 and its binding protein in the pathogenesis of ITP.

Inflammation promotes oral squamous carcinoma immune evasion via induced programmed death ligand-1 surface expression

The association between inflammation and cancer provides a new target for tumor biotherapy. The inflammatory cells and molecules within the tumor microenvironment have decisive dual roles in antitumor immunity and immune evasion. In the present study, phytohemagglutinin (PHA) was used to stimulate peripheral blood mononuclear cells (PBMCs) to simulate the tumor inflammatory microenvironment. The effect of immune cells and inflammatory cytokines on the surface expression of programmed cell death-1 ligand 1 (PD-L1) and tumor immune evasion was investigated using flow cytometry (FCM) and an in vivo xenotransplantation model. Based on the data, PHA-activated, but not resting, immune cells were able to promote the surface expression of PD-L1 in Tca8113 oral squamous carcinoma cells via the secretion of inflammatory cytokines, but not by cell-cell contact. The majority of the inflammatory cytokines had no significant effect on the proliferation, cell cycle progression and apoptosis of the Tca8113 cells, although they each induced the expression of PD-L1 in a dose-dependent manner. In total, 99% of the Tca8113 cells expressed PD-L1 following treatment with the supernatant of PHA-stimulated PBMCs. The PHA-supernatant pretreated Tca8113 cells unusually induced Tca8113 antigen-specific CD8⁺ T cell apoptosis in vitro and the evasion of antigen-specific T cell attraction in a nude mouse tumor-bearing model. These results indicate a new mechanism for the promotion of tumor immune evasion by the tumor inflammatory microenvironment

Induced cytokine response of human PMBC-cultures: correlation of gene expression and secretion profiling and the effect of cryopreservation

The immune system is regulated by the complex interaction of multiple cytokines, which are secreted signaling molecules affecting other cells. In this work, we studied the cytokine response to several well-known stimulants, such as OKT-3, Con A, PWM, and SEB. Healthy donor cells (PBMCs) were cultivated for up to 72 h and the mRNA levels and cytokine release of four key cytokines (IL-2, IL-4, IFN-γ, and TNF-α) were analyzed by RT-PCR and bead-based multiplex analyses. The generated cytokine profiles showed characteristic expression patterns and secretion kinetics for each cytokine and substance. PWM/SEB and OKT-3 led to a very fast and long-lasting immune response, whereas Con A induced the slowest cytokine production. Cytokine concentrations also differed greatly. The highest IFN-γ concentration was 1000 times higher than the respective IL-4 concentration. Gene expression and cytokine concentration profiles were strongly correlated during the time course. The chronological response of the donors' cytokine profiles coincided, but showed individual characteristics regarding the strength of the cytokine release. The comparison of stimulation experiments using freshly isolated and cryopreserved PBMCs showed that, for the observation of an immunological response at early points in time, gene expression experiments are more reliable than the measurement of cytokines in the cell culture supernatant. However, the freezing of cells influences the response significantly. The measurement of secreted proteins is the superior method at later points in time.

Sequencing of a second interleukin-10 gene in rainbow trout Oncorhynchus mykiss and comparative investigation of the expression and modulation of the paralogues in vitro and in vivo

Interleukin-10 (IL-10) is a multifaceted cytokine that is produced by and effects a variety of cell populations, including macrophages, T, B and NK cells. The gene encoding for IL-10 has been isolated in mammals, birds, amphibians and recently in fish, with only single copy identified in each species. We report here a second IL-10 gene (tIL-10b) in rainbow trout that showed 92% identity in the coding region but only 50% identity in the 5'- and 3'-UTR to the known trout IL-10 paralogue, which we have now called tIL-10a. There is a short upstream open reading frame (uORF) within the 5'-untranslated region (UTR) of tIL-10a that may inhibit its translation, whilst in tIL-10b multiple mRNA instability motifs exist in the 3'-UTR, suggesting that the two IL-10 paralogues may have different mechanisms to regulate their expression post-transcriptionally. The expression of tIL-10a is generally higher than that of tIL-10b in most of the fourteen tissues examined and in the RTS-11, RTL and RTGill cell lines. However, the expression level of tIL-10b can exceed that of tIL-10a, as seen in vivo in the ovary of healthy fish and in the gills of Yersinia ruckeri challenged fish, and in vitro in head kidney (HK) leucocytes cultured for ≥ 8 h. The expression of the trout IL-10 paralogues can be up-regulated by LPS and polyIC in RTS-11 cells and by LPS, polyIC, PHA, PMA, calcium ionophore (CI) and IL-21 in head kidney leucocytes, as well as by Y. ruckeri infection, and can be modulated positively or negatively by IFN-γ. Synergistic effects on up-regulation of IL-10 expression were also seen between PHA and IL-21, as well as between PMA and CI. The expression kinetics of the IL-10 paralogues was also found to be different, suggesting that rainbow trout has evolved different pathways to regulate the expression of the two IL-10 paralogues at the transcriptional level.

Inorganic arsenic alters expression of immune and stress response genes in activated primary human T lymphocytes

Inorganic arsenic, a carcinogenic environmental contaminant, exerts immunosuppressive effects on human T lymphocytes. In particular, interleukin-2 (IL2) secretion and T cell proliferation are reduced when peripheral blood mononuclear cells (PBMC) from individuals chronically exposed to arsenic are stimulated ex vivo with lectins such as phytohemaglutinin (PHA). However, it is not clear whether the metalloid directly acts on T cells or blocks monocyte-dependent accessory signals activated by PHA. We report that in vitro pre-treatment of PBMC with sodium arsenite (NaAs) reduces IL2 secretion and T cell proliferation induced by PHA, but does not prevent expression of monocyte-derived cytokines (IL1, IL6, TNFα) functioning as lymphocyte-activating factors. In addition, we found that NaAs delays induction of IL2 and IL2 receptor α chain (IL2RA) mRNA levels in human primary isolated T cells activated by PHA. Kinetic analysis showed that NaAs pre-treatment first inhibits, but thereafter markedly increases, induction of IL2 and IL2RA mRNA when T cells are stimulated with PHA for 8 h and 72 h, respectively. We conducted whole genome microarray-based analysis of gene expression in primary T cell cultures derived from independent donors. NaAs systematically and significantly up-regulated a set of 35 genes, including several immune and stress genes, such as IL13, granulocyte-macrophage colony stimulating factor, lymphotoxin α and heme oxygenase-1 (HO-1). Up-regulation of HO-1, a stress and immunosuppressive protein, was rapidly detectable, both in T cells and in PBMC treated with NaAs. Inhibition of the immunosuppressive activity of HO-1 in PBMC however failed to prevent NaAs-dependent inhibition of T cell proliferation induced by PHA. Our findings demonstrate that, at least in vitro, inorganic arsenic acts directly on human T cells and impairs their activity, probably independently of HO-1 expression and monocyte-related accessory signals.

Comparisons of affinities, avidities, and complement activation of adalimumab, infliximab, and etanercept in binding to soluble and membrane tumor necrosis factor

The TNF antagonists adalimumab, infliximab, and etanercept are effective treatments for rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and psoriasis, but only adalimumab and infliximab have been found to be efficacious in Crohn's disease. The present studies evaluated the TNF-binding and complement-activating properties of adalimumab, infliximab, and etanercept to determine whether these properties may explain differences in their clinical efficacy profiles. Association and dissociation rates of binding to soluble TNF were measured by surface plasmon resonance, and were found to be similar for adalimumab, infliximab, and etanercept, as were their calculated binding affinities. Avidity of binding to soluble TNF, measured by KinExA technology, was 10- to 20-fold greater for soluble etanercept (K(D)=0.4 picomolars [pM]) than for soluble adalimumab or infliximab (K(D)=8.6 and 4.2 pM, respectively). (125)I-adalimumab, -infliximab, and -etanercept bound to membrane TNF (mTNF) on mTNF-transfected cells with similar affinities (K(D)=483, 468, and 445 pM, respectively) that were each lower than for soluble TNF. Complement-dependent cytotoxicity (CDC) was induced in mTNF-transfected cells by adalimumab and infliximab, but was not induced in activated normal human PBMC by any of the 3 agents. In conclusion, the binding properties of adalimumab, infliximab, and etanercept were similar for soluble TNF, and very similar for mTNF, yet none of the 3 was able to induce CDC in activated PBMC. These results suggest that the different clinical efficacy profiles of these agents are not explained by differences in either TNF-intrinsic binding properties or complement lysis.

Analysis of the immune responses in chimpanzees infected with HIV type 1 isolates

The mechanisms of resistance to AIDS development in HIV-1-infected chimpanzees have remained elusive. Unique among chimpanzees naturally or experimentally infected with HIV, several animals of the Yerkes cohort have progressed to clinical AIDS with selection of isolates showing increased pathogenicity for chimpanzees. We compared progressors vs. nonprogressors among the HIV-infected chimpanzees that made up this cohort, eight of which have been infected with HIV-1 for over 14 years. The additional two progressors were infected de novo with chimpanzee-pathogenic HIV, rapidly leading to a progressor status. Nonprogressors were characterized by normal CD4(+) T cell counts and the absence of detectable viremia. In contrast, progressor chimpanzees had relatively high plasma viral loads associated with a dramatic loss of CD4(+) T cells. The analysis of immune responses showed a similar amplitude and breadth of ELISPOT T cell responses in both groups. HIV-specific proliferative responses were, however, absent in the progressor animals, which also exhibited increased levels of immune activation characterized by elevated levels of the circulating chemokines IP-10 and MCP-1. Of interest was the conservation of potent NK cell activity in all animals, potentially contributing to the extended symptom-free survival of progressor animals. Modest anti-HIV antibody titers were detectable in the nonprogressor group, but these antibodies exhibited good neutralizing activity. In progressors, however, two sets of data were noted: in animals that gradually selected for pathogenic isolates, or that were superinfected, very high neutralizing antibody titers were observed, although none to the pathogenic HIV. In contrast, two animals infected de novo with chimpanzee pathogenic HIV failed to mount an extensive humoral response and both failed to develop neutralizing antibodies to the virus. Taken together, pathogenic HIV infection in chimpanzees is associated with rapid loss of CD4(+) T cells and proliferative responses as well as higher levels of immune activation.

Long-term effects of idiotype vaccination on the specific T-cell response in peripheral blood and bone marrow of multiple myeloma patients

OBJECTIVES

To elucidate long-term effects of idiotype (Id) vaccination on Id-specific T cells of multiple myeloma (MM) patients and compare Id-specific T-cell responses of peripheral blood with those of bone marrow (BM).

MATERIALS AND METHODS

Id-specific T-cell responses of peripheral blood mononuclear cells (PBMC) were compared with those of BM mononuclear cells (BMMC) in 10 MM patients vaccinated with the Id protein at a median time of 41 months since the last immunization. The PBMC responses at late follow-up were also compared with those during active immunization. The responses were assessed by a proliferation assay, enzyme-linked immunospot (ELISPOT) (gamma-interferon), cytometric bead array (CBA) for secreted cytokines and quantitative real-time polymerase chain reaction (QRT-PCR) for cytokine gene expression.

RESULTS

At the late testing time, an Id-specific response was detected in PBMC of five patients (ELISPOT, CBA, QRT-PCR) and in BMMC of four patients (CBA, QRT-PCR). A response in both compartments was noted only in three patients. The cytokines gene profile was consistent with a predominance of Th(2) cells [interleukin (IL)-4, IL-5, IL-10]. Comparison of the Id-specific responses of PBMC during active immunization with those at the late follow-up showed that the frequency and magnitude of the responses had decreased significantly by time (proliferation/ELISPOT) (P < 0.02) and shifted at the gene level from a Th(1) to a Th(2) profile (P < 0.05).

CONCLUSION

Id-specific T-cells may decline overtime and shift toward a Th(2) response and may be found at a similar frequency of patients in blood and BM.

Quantitative gene expression of cytokines in peripheral blood leukocytes stimulated in vitro: modulation by the anti-tumor nerosis factor-alpha antibody infliximab and comparison with the mucosal cytokine expression in patients with ulcerative colitis

Emerging data indicate that alterations in cytokine synthesis play a role in inflammatory bowel disease (IBD) pathogenesis. In this study, we quantified mRNA expression of the main acute-phase cytokines and T-cell cytokines in biopsies from patients with established ulcerative colitis (UC) and compared it with that obtained in biopsies from normal controls. Quantification of cytokine gene expression was also evaluated in in vitro phytohemagglutinin (PHA)-treated peripheral blood leukocytes (PBLs) at the RNA and protein levels. The in vitro influence of the anti-tumor necrosis factor-alpha (TNF-alpha) antibody infliximab (INFL) on PHA-treated PBLs was also evaluated. Analyzing inflamed specimens from UC patients compared with control samples, interleukin (IL)-6 was sharply the most induced cytokine. Interestingly, similar results were found in activated PBLs, where acute-phase cytokines were more abundantly expressed compared with T-cell cytokines. IL-6 was confirmed to be the most induced with a maximum increase of 1110-fold after 4 h of PHA stimulation, followed by TNF-alpha and IL-1beta as well as interferon-gamma (IFN-gamma). Surprisingly, analyzing cytokine-mRNA expression from activated PBLs, the time kinetics and quantity of IFN-gamma was more similar to that of the acute-phase proteins than to that of the T-cell cytokines, which were upregulated after 1 h. The upregulation of cytokine-mRNA was translated into protein as demonstrated by enzyme-linked immunosorbent assay. IFN-gamma was also strongly expressed in the RNA from UC biopsies. TNF-alpha protein was not detectable at all in INFL-treated cultures. INFL did not induce a reduction of TNF-alpha-mRNA nor of IL-1beta-mRNA, but it reduced IFN-gamma- mRNA and, to a lesser extent, IL-6-mRNA; it also reduced the T-cell-derived cytokine IL-2. The in vitro model of PHA-stimulated PBLs may mimic inflammation processes observed in vivo. INFL may reduce inflammation in vivo through inhibition of both monocyte and T-cell activation.

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.

Immunomodulation produced by a green propolis extract on humoral and cellular responses of mice immunized with SuHV-1

Despite recent technological advances in vaccine production, most the vaccines depend on the association with adjuvant substances. This work evaluated the adjuvant capacity of an ethanol extract of green propolis associated to inactivated Suid herpesvirus type 1 (SuHV-1) vaccine preparations. Mice inoculated with SuHV-1 vaccine plus aluminum hydroxide and 5mg/dose of propolis extract presented higher levels of antibodies when compared to animals that received the same vaccine without propolis. The use of SuHV-1 vaccine with propolis extract alone did not induce significant levels of antibodies, however it was able to increase the cellular immune response, evidenced by the increase in the expression of mRNA to IFN-gamma. Besides, propolis increased the percentage of protected animals against challenge with a lethal dose of SuHV-1. The effect of green propolis extract on the humoral and cellular immune responses may be exploited for the development of effective vaccines.

Expression of chemokine-like factor 1 is upregulated during T lymphocyte activation

Chemokine-like factor 1 (CKLF1) is a cytokine with chemotactic effects on leukocytes and a functional ligand of CCR4. This cytokine is widely expressed and the level of expression is reported to be upregulated in asthma and rheumatoid arthritis (RA), disease conditions in which T lymphocytes are over-activated. In order to determine the expression profile of CKLF1 in activated T lymphocytes, we first employed a PCR-based method on human blood fractions cDNA panels and found that CKLF1 was upregulated in activated CD4+ and CD8+ cells, with no obvious changes in CD19+ cells. We further performed kinetic analyses of CKLF1 expression in phytohemagglutinin (PHA)-stimulated human peripheral blood lymphocytes (PBL) at both the mRNA and protein levels. In resting PBL, the constitutive expression of CKLF1 was low at mRNA level and barely detectable at the protein level; however, both were remarkably upregulated by PHA, appearing at 8h after PHA-stimulation and persisting up to 72h. These results suggest that CKLF1 may be involved in T lymphocyte activation and further study of CKLF1 function will prove valuable.

Performance of a T-cell-based diagnostic test for tuberculosis infection in HIV-infected individuals is independent of CD4 cell count

The performance characteristics of the enzyme-linked immunospot assay (ELISPOT) assay (T-SPOT TB) for the diagnosis of latent tuberculosis infection in HIV-infected individuals are unknown. Given that ELISPOT enumerates Mycobacterium tuberculosis antigen-specific IFN-gamma-secreting T cells, HIV-associated immunosuppression might adversely affect test performance. However, we found that 28 out of 29 HIV-positive individuals (97%) gave evaluable test results, and performance was independent of the CD4 T-cell count. ELISPOT test performance appears to be independent of HIV-associated immunosuppression.

In vitro and in vivo effects of mercuric chloride on thymic endocrine activity, NK and NKT cell cytotoxicity, cytokine profiles (IL-2, IFN-gamma, IL-6): role of the nitric oxide-L-arginine pathway

Mercury (Hg2+) affects cell-mediated immunity, including thymulin production. Thymulin, a zinc-dependent thymic hormone synthesized by thymic epithelial cells (TECs), is involved in NK cell cytotoxicity and Th1 cytokine production (IL-2 and IFN-gamma), which in turn affect both NKT and classic NK spleen cell cytotoxicity. High doses of Hg2+ induce an inflammatory status, increased production of IL-6 and consequent Th1/Th2 imbalance as well as cell-mediated immune depression. The mechanisms by which Hg+ affects the cell-mediated immune response are still unclear. The nitric oxide (NO) pathway may be implicated. The aim of this work was to further explore its noxious role in innate and adaptive immunity and to study the possible role played by the NO pathway. Young Balb/c mice treated in vivo for 1 month with 1.0 mg HgCl2/kg b.w. showed low thymulin activity, depressed NO production (as measured by nitrite and nitrate plasma levels), impaired classic NK spleen cell cytotoxicity, decreased Th1 (IL-2 and IFN-gamma) cytokine profiles, and increased IL-6 production. In vitro, 10(-6) M of HgCl2 inhibited active thymulin kinetics, TEC proliferation, NKT cell cytotoxicity and Th1 cytokine production, whereas IL-6 increased. L-arginine restored thymulin activity, TEC proliferation, NKT cytotoxicity, cytokine profiles and nitrite and nitrate plasma levels both in vivo and in vitro. Since L-arginine is the substrate for NO production, it may compensate for the cell-mediated immune defect induced by HgCl2, via the arginine-NO-pathway. L-arginine is also able to reduce glomerular kidney IgG antibodies deposits induced by higher dose of HgCl2 administration.

C3 binding glycoprotein from Cuscuta europea induced different cytokine profiles from human PBMC compared to other plant and bacterial immunomodulators

The immunomodulatory properties of bioactive agents include the ability to induce cytokine production by the activated target cell. The effect of immunomodulatory C3 binding glycoprotein isolated from Cuscuta europea on the induction of human PBMC cytokine synthesis and the cell viability was investigated. Isolated PBMC from healthy donors were cultured for 24 h with C3bgp. We also studied the influence of C3bgp on the cytokine production in LPS, PHA, PWM and Dex treated PBMC. The quantitative determination of TNF-alpha, IL-12, IL-6 and IL-10 was performed in culture supernatant by ELISA. Results obtained demonstrated that C3bgp induced proinflammatory and immunoregulatory cytokine production, in the highest degree IL-12, followed by IL-6 and in lower degree TNF-alpha. IL-12 quantity was significantly increased in C3bgp stimulated cultures in comparison with LPS, PHA and PWM stimulated PBMC. C3bgp also increased IL-12 in PHA or PWM stimulated cultures, but not in LPS stimulated culture. C3bgp significantly increased IL-6 production compared to the PHA and PWM but not to LPS stimulation. On the other side, C3bgp inhibited IL-10 production after LPS, PHA and PWM stimulation. Cell viability in C3bgp stimulated cultures retained on the same level from 72 to 120 h of culturing, in contrast to LPS and PHA stimulated cultures. Based on the results presented, we conclude that the C3bgp exhibited immunomodulatory properties on the human PBMC. The ability of PDTC and Dex to down-regulate the effect of C3bgp on the proinflammatory cytokine production suggests that a part of the mechanism of action of C3bgp is mediated through NF-kB signal transduction pathway.

HIV-1 does not provoke alteration of cytokine gene expression in lymphoid tissue after acute infection ex vivo

The cytokine response to invading microorganisms is critical for priming the adaptive immune response. During acute HIV infection, the response is disrupted, but the mechanism is poorly understood. We examined the cytokine response in human lymphoid tissue, acutely infected ex vivo with HIV. Lymphoid tissue was cultured either as blocks or as human lymphocyte aggregate cultures (HLAC) of tonsils and lymph nodes. This approach allowed us to examine the effects of HIV on cytokines using distinct culture techniques. In contrast to HLAC, mock-infected tissue blocks displayed a 50- to 100-fold up-regulation of mRNAs for IL-1beta, -6, and -8 in the first 6 days of culture. Parallel increases were also noted at the protein level in the supernatants. Although IL-1beta, -6, and -8 are known to synergistically enhance HIV replication, peak HIV replication (measured as p24 Ag) was similar in tissue blocks and HLAC. Surprisingly, vigorous HIV replication of CXCR4- and CCR5-tropic HIV strains did not result in characteristic mRNA profiles for IL-1beta, -2, -4, -6, -8, -10, -12, -15, IFN-gamma, TNF-alpha, TGF-beta, and beta-chemokines in tissue blocks or HLAC. The increased expression of IL-1beta, -6, and -8 in tissue blocks may approximate clinical situations with heightened immune activation; neutralization of these cytokines resulted in inhibition of HIV replication, suggesting that these cytokines may contribute to HIV replication in certain clinical settings. These results also indicate that different molecular mechanisms govern HIV replication in tissue blocks and HLAC. Prevention of effective cytokine responses may be an important mechanism that HIV uses during acute infection.

An in vitro bioassay to determine individual sensitivity to glucocorticoids: induction of FKBP51 mRNA in peripheral blood mononuclear cells

Individual variation in sensitivity to glucocorticoids (GCs) poses a dilemma to the clinician. Currently available assays to determine individual sensitivity to GCs either seem imprecise, or they are based on mitogen-activated lymphocytes, although mitogens themselves may affect cellular GC sensitivity. To avoid these disadvantages, we developed an assay based on the GC-induced accumulation of the 51kDa FK506 binding protein (FKBP51) mRNA in unstimulated peripheral blood mononuclear cells (PBMC), measured using real time PCR. Of several family members tested, only FKBP51 transcript levels showed to be GC-inducible. Furthermore, our bioassay was not affected by progesterone, estradiol, and testosterone. Immunological stimulation of PBMC using tetanus toxoid did not affect bioassay results, and isolated T- and B-lymphocytes showed a similar response to GC stimulation. The intra- and inter-assay variations were 10.6 and 15.9%, respectively. Our bioassay confirms previous reports that a wide variation in GC sensitivity exists in the normal population, yet is able to clearly discriminate a patient with familial GC hyposensitivity from controls. Our bioassay may be suitable to assess altered individual GC sensitivity, and the small amount of PBMC needed for a determination makes this assay easily applicable in a pediatric setting.

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.

Optimal kinetics for quantification of antigen-induced cytokines in human peripheral blood mononuclear cells by real-time PCR and by ELISA

Real-time polymerase chain reaction (PCR) has recently been described as a new tool to measure and accurately quantify mRNA levels. In this study, we have applied this technique to evaluate cytokine mRNA synthesis induced by antigenic stimulation with purified protein derivative (PPD) or heparin-binding haemagglutinin (HBHA) in human peripheral blood mononuclear cells (PBMC) from Mycobacterium tuberculosis-infected individuals. Whereas PPD and HBHA optimally induced IL-2 mRNA after respectively 8 and 16 to 24 h of in vitro stimulation, longer in vitro stimulation times were necessary for optimal induction of interferon-gamma (IFN-gamma) mRNA, respectively 16 to 24 h for PPD and 24 to 96 h for HBHA. IL-13 mRNA was optimally induced by in vitro stimulation after 16-48 h for PPD and after 48 to 96 h for HBHA. Comparison of antigen-induced Th1 and Th2 cytokines appears, therefore, valuable only if both cytokine types are analysed at their optimal time point of production, which, for a given cytokine, may differ for each antigen tested. Results obtained by real-time PCR for IFN-gamma and IL-13 mRNA correlated well with those obtained by measuring the cytokine concentrations in cell culture supernatants, provided they were high enough to be detected. We conclude that real-time PCR can be successfully applied to the quantification of antigen-induced cytokine mRNA and to the evaluation of the Th1/Th2 balance, only if the kinetics of cytokine mRNA appearance are taken into account and evaluated for each cytokine measured and each antigen analysed.

Real-time polymerase chain reaction monitoring of epithelial cell adhesion molecule-induced T-cell stimulation in patients with lung cancer and healthy individuals using LightCycler technology

The epithelial cell adhesion molecule is strongly expressed in carcinomas of diverse histologic origin and has attracted attention as a target for immunotherapy. We have previously demonstrated that the epithelial cell adhesion molecule-derived human leukocyte antigen-A*0201-restricted nonamer peptide ILYENNVIT(184-192) can be efficiently recognized by peptide-specific cytotoxic T lymphocytes (CTL). Using this peptide (Ep-2) we could readily expand precursor CTL and demonstrate their cytotoxicity by standard chromium-release assay. We now sought to evaluate the immune reactivity of Ep-2-specific CTL expanded from the peripheral blood mononuclear cells by real-time quantitative polymerase chain reaction assay (LightCycler system) measuring the change in interferon-gamma mRNA levels upon stimulation. Cytotoxic T lymphocyte response against the Ep-2 peptide in two patients with epithelial cell adhesion molecule-expressing lung cancer and three healthy donors was compared with the chromium-release assay. In vitro expanded epithelial cell adhesion molecule-specific CTL precursors that exhibited significantly elevated interferon-gamma mRNA levels also lysed Ep-2 peptide-pulsed target cells. Our study indicates that quantitative polymerase chain reaction may be a supplement to chromium-release assay for monitoring in vitro expanded CTL precursor reactivity.

Upregulation of IFN-gamma and soluble interleukin-2 receptor release and altered serum cortisol and prolactin concentration during general anesthesia

The effects of surgery, surgical stress, and anesthesia compromise the optimal function of the immune system. Recent studies demonstrate the influence of anesthesia on the immune response by modulation of neural-immune interactions. To evaluate the immunologic effects of general anesthesia with the hypnotic agent propofol and the opioid fentanyl, two drugs used frequently in anesthesia, we studied 30 patients undergoing elective orthopedic surgery before and during narcosis. We found a significant enhancement of interferon-gamma (IFN-gamma) and soluble interleukin-2 receptor (sIL-2R) release in lipopolysaccharide (LPS)-stimulated whole blood cultures after induction of anesthesia. Similar results were observed in cultures stimulated with polyclonal T cell activators, such as staphylococcal enterotoxin B (SEB) and phytohemagglutinin (PHA). IL-1beta and IL-8 release was not affected, but the anti-inflammatory cytokine IL-10 decreased after skin incision. Serum prolactin significantly increased immediately after induction of anesthesia, whereas serum cortisol levels declined. Our results point to enhanced proinflammatory T lymphocyte and natural killer (NK) cell activity, probably caused by prolactin and cortisol modulation in the serum. This may disturb the balance of human proinflammatory and anti-inflammatory pathways during surgery and general anesthesia.

Fulminant radiation-induced necrosis after stereotactic radiation therapy to the posterior fossa. Case report and review of the literature

The problem of radiation-induced necrosis of normal brain surrounding the target area has been a major catalyst for the development of stereotactically focused radiation therapy. According to current opinion, the effects of stereotactic irradiation are confined to the region targeted. The authors present a case in which the administration of a conventional dose of stereotactically focused irradiation for treatment of a pilocytic astrocytoma produced fulminant necrosis that necessitated a combination of intensive surgical and medical management, after which the patient improved over the course of 1 year. Concomitant with his improvement, the initially remarkable findings on magnetic resonance imaging gradually resolved. In this presentation the authors emphasize the need to evaluate alternatives carefully before a decision is made to administer therapeutic irradiation. Furthermore, they explore the roles that target, host, and dosage factors play in hypersensitivity to radiation injury, the detection of these factors before treatment, and the administration of radioprotective agents. With the growing use of stereotactically focused irradiation as a primary treatment modality for a variety of neurosurgical conditions, it is important to be cognizant of its uncommon but potentially lethal side effects. A cooperative multicenter database in which the outcomes and morbidity following stereotactic irradiation are recorded is essential to the detection of relatively uncommon but severe complications such as those observed in this case.

Changes in serum levels of cytokines in mice injected with an immunostimulator C3bgp isolated from Cuscuta europea

The effect of C3 binding glycoprotein (C3bgp), isolated from Cuscuta europea seeds on induction of in vivo cytokine synthesis was investigated. Different groups of mice were stimulated with 30 microg C3bgp per mouse, injected intraperitoneally. The quantitative determination of IL-1alpha, IL-2, IL-4, IL-6, IL-10, TNF-alpha and IFN-gamma was performed in mouse sera by ELISA. The quantities of these cytokines were measured at different hours: 1, 2, 3, 4, 5, 6, 7, and 24 h after injection. No significant changes in serum level of IL-2, IL-4 and TNF-alpha in experimental animal groups were found. A little increase of IL-1alpha, moderate elevation of IL-10 and IFN-gamma (5- to 6-fold more) and strong release, more than 10-fold of IL-6 in sera of C3bgp-treated mice were detected. The results obtained from C3bgp stimulated cultures of mouse peritoneal macrophages and mouse splenocytes suggest that C3bgp binds to mouse peritoneal macrophages and induces production mainly of IL-6, followed by IFN-gamma and in a very low degree of IL-1alpha and IL-10. Based on the results presented, we conclude that the increased level of IL-6 was the basic after injection of C3bgp and that the mouse macrophages were the major cell targets for the C3bgp effect.

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

Quantitation of cytokine production is a valuable adjunct to standard immunologic assays in defining several pathologic processes. Nevertheless, there is little agreement about which tissues should be assayed, which type of assay should be performed, and which stimulation protocol should be used. As these types of assays enter the clinical arena, there is need for standardization. There is also a need to maximize the amount of information which may be derived from a single sample. We compared secreted interleukin 4 (IL-4), IL-2, IL-6, tumor necrosis factor alpha (TNF-alpha), and gamma interferon proteins as measured by enzyme-linked immunosorbent assay with intracellular cytokine production (IL-2 and gamma interferon) as detected by flow cytometry and quantitative competitive PCR for IL-2, IL-4, TNF-alpha, and gamma interferon mRNA and cDNA. Results from unstimulated cells and cells stimulated with phorbol myristate acetate, phytohemagglutinin, and phorbol myristate acetate plus phytohemagglutin were compared. All three methodologies detected significant stimulation of cytokine production. The combination of phytohemagglutinin and phorbol myristate acetate was overall the most-potent stimulus.

Cytokine gene expression occurs more rapidly in stimulated peripheral blood mononuclear cells from human immunodeficiency virus-infected persons

Evaluation of cytokine gene expression following in vitro stimulation is one means of examining the dysregulation of the immune system in human immunodeficiency virus (HIV) infection. We have assessed differences in the immune status of non-HIV-infected (HIV-) and HIV-infected (HIV+) individuals by evaluating the kinetics of the expression of cytokine genes. We compared detailed time courses of cytokine mRNA expression in HIV- and HIV+ peripheral blood mononuclear cells (PBMC) and found that there is a significant shift (P<0.01) for all cytokines examined (interleukin 2 [IL-2], IL-6, IL-10, gamma interferon, and tumor necrosis factor alpha [TNF-alpha]) to an earlier time of mean peak mRNA expression by HIV+ PBMC (between 4 and 8 h) compared to HIV- PBMC (8 h) in response to either phytohemagglutinin (PHA) or anti-CD3 stimulation. Additional studies showed that although PHA-stimulated HIV+ PBMC showed decreased median IL-2, IL-4, and TNF-alpha mRNA levels, they typically demonstrated more rapid kinetics (increased mean 4-h/24-h cytokine mRNA ratios), with significant differences for IL-4 (P<0.05) and TNF-alpha (P<0.005), compared to HIV- PBMC. The use of fresh or frozen cells gave comparable cytokine mRNA data; however, the secretion of some cytokine proteins (IL-2 receptor, IL-10, and TNF-alpha) appeared to be reduced in HIV+ PBMC that had been frozen and thawed. Our studies demonstrate that the kinetics of cytokine gene expression can reveal additional dysregulation of the immune system in HIV infection, suggesting that PBMC of HIV-infected persons exist in an activated state in vivo that permits them to express cytokine genes more rapidly than a normal PBMC.

T(H)1 to T(H)2 shift of cytokines in peripheral blood of HIV-infected patients is detectable by reverse transcriptase polymerase chain reaction but not by enzyme-linked immunosorbent assay under nonstimulated conditions

BACKGROUND

Dysregulation of cytokines has been implicated in the pathogenesis of HIV infection. Therefore, we determined tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-4, IL-10, and interferon-gamma (IFN-gamma) mRNA and serum levels in HIV-infected patients under nonstimulated conditions.

MATERIAL AND METHODS

Blood samples of 32 HIV-infected patients and 10 healthy HIV-negative controls were analyzed. Cytokine serum levels were quantified by enzyme-linked immunosorbent assay (ELISA). Cytokine mRNA levels were determined semiquantitatively by competitive reverse transcriptase polymerase chain reaction (RT-PCR) and expressed as ratios relative to those of beta-actin.

RESULTS

Competitive RT-PCR was shown to be more sensitive than protein ELISA in analyzing cytokine production. We found a significant correlation between steady-state mRNA ratios and serum protein levels for TNF-alpha. Significantly higher cytokine mRNA ratios were found in those patients with IL-10 and IFN-gamma levels detectable by ELISA. Steady-state mRNA ratios of TNF-alpha, IL-4, and IL-10 were significantly increased in patients with highly replicative HIV-infection. Furthermore, elevated IL-4:IFN-gamma ratios were related to both high viral load and loss of CD4 cells.

DISCUSSION

Determination of steady-state mRNA ratios by semiquantitative RT-PCR represents a sensitive method to analyze cytokines in peripheral blood of HIV-infected patients under nonstimulated conditions. The data obtained with this technique provide further evidence for a T(H)1 to T(H)2 cytokine shift with progressive HIV disease.

Th1 cytokine patterns in cervical human papillomavirus infection

The host's immune response to cervical human papillomavirus (HPV) infection is poorly understood. In a longitudinal cohort of women with cervical HPV infections, defined by PCR-based HPV DNA testing, we used exfoliated cervical cells and reverse transcription-PCR to examine the cervical mucosal mRNA expression of cytokines involved in regulating cell-mediated immunity. We identified seven HPV-positive subjects who were found to have cleared their HPV infections 4 months later. In all seven, a T-helper type 1 (Th1) cytokine pattern (expression of gamma interferon and absence of interleukin-4) preceded clearance. The more variable cytokine patterns seen in HPV-negative subjects suggest that the Th1 pattern in the women with subsequent clearance was a response to the HPV infection. This contention is supported by additional cross-sectional data showing a Th1 pattern in a majority of HPV-positive women. This study establishes a feasible means for assessing local cytokine expression in the cervical milieu and demonstrates that a Th1 cytokine response is associated with subsequent clearance of cervical HPV infection.