Dysregulated cytokine expression by CD4+ T cells from post-septic mice modulates both Th1 and Th2-mediated granulomatous lung inflammation

Previous epidemiological studies in humans and experimental studies in animals indicate that survivors of severe sepsis exhibit deficiencies in the activation and effector function of immune cells. In particular, CD4+ T lymphocytes can exhibit reduced proliferative capacity and improper cytokine responses following sepsis. To further investigate the cell-intrinsic defects of CD4+ T cells following sepsis, splenic CD4+ T cells from sham surgery and post-septic mice were transferred into lymphopenic mice. These recipient mice were then subjected to both TH1-(purified protein derivative) and TH2-(Schistosoma mansoni egg antigen) driven models of granulomatous lung inflammation. Post-septic CD4+ T cells mediated smaller TH1 and larger TH2 lung granulomas as compared to mice receiving CD4+ T cells from sham surgery donors. However, cytokine production by lymph node cells in antigen restimulation assays indicated increased pan-specific cytokine expression by post-septic CD4+ T cell recipient mice in both TH1 and TH2 granuloma models. These include increased production of T(H)2 cytokines in TH1 inflammation, and increased production of T(H)1 cytokines in TH2 inflammation. These results suggest that cell-intrinsic defects in CD4+ T cell effector function can have deleterious effects on inflammatory processes post-sepsis, due to a defect in the proper regulation of TH-specific cytokine expression.     

Single chamber microbial fuel cell with spiral anode for dairy wastewater treatment

The circulating population of peripheral T lymphocytes obtained from a blood sample can provide a large amount of information about an individual's medical status and history. Recent evidence indicates that the detection and functional characterization of antigen-specific T cell subsets within the circulating population may provide a diagnostic indicator of disease and has the potential to predict an individual's response to therapy. In this report, a microarray detection platform that combines grating-coupled surface plasmon resonance imaging (GCSPRI) and grating-coupled surface plasmon coupled emission (SPCE) fluorescence detection modalities were used to detect and characterize CD4(+) T cells. The microspot regions of interest (ROIs) printed on the array consisted of immobilized antibodies or peptide loaded MHC monomers (p/MHC) as T cell capture ligands mixed with additional antibodies as cytokine capture ligands covalently bound to the surface of a corrugated gold sensor chip. Using optimized parameters, an unlabeled influenza peptide reactive T cell clone could be detected at a frequency of 0.1% in a mixed T cell sample using GCSPRI. Additionally, after cell binding was quantified, differential TH1 cytokine secretion patterns from a T cell clone cultured under TH1 or TH2 inducing conditions was detected using an SPCE fluorescence based assay. Differences in the secretion patterns of 3 cytokines, characteristic of the inducing conditions, indicated that differences were a consequence of the functional status of the captured cells. A dual mode GCSPRI/SPCE assay can provide a rapid, high content T cell screening/characterization tool that is useful for diagnosing disease, evaluating vaccination efficacy, or assessing responses to immunotherapeutics.     

The kinetics and stimulant dependence of cytokine production by blood and bronchoalveolar lavage T cells evaluated at the single cell level.

We have previously shown that bronchoalveolar lavage (BAL) T cells from human airways predominantly produce interferon gamma (IFN-gamma) and interleukin 2 (IL-2) when stimulated ex vivo. The kinetics of TH1 and TH2 cell cytokine production by T cells from both blood and BAL were studied to establish the optimal time after stimulation either with pharbol myristate (PMA) and ionomycin or with the more physiological stimulus of anti-CD3 for intracellular cytokine detection of IFN-gamma, IL-2, IL-4 and IL-5 in both blood and BAL T cells. The optimal time for positive identification of IL-2 in both blood and BAL was 5 h after PMA/ionomycin stimulation, whereas the first peak for IFN-gamma was found after 5 h in blood but after only 3 h in BAL. T cells from different biological compartments responded differently to each of the stimuli. Whilst anti-CD3 stimulation did not induce TH1 cytokine production in blood T cells, it readily induced both IFN-gamma and IL-2 production in BAL T cells. The kinetics of cytokine production were found to be stimulus dependent. Whilst IL-2 production showed similar kinetics with both stimuli, the kinetics of IFN-gamma production differed between stimuli. We have also examined the effect of five different stimuli on cytokine production by T cells to determine whether different forms of stimulation may selectively stimulate or inhibit different cytokines. Not surprisingly, PMA/ionomycin induced a greater percentage of BAL T cells to produce TH1 cytokines. However, other than modest amounts of the TH2 cytokines IL-4 and IL-5 were not induced by any of the five stimuli.     

Heterogeneous cytokine production by acutely stimulated bronchoalveolar T lymphocytes in reovirus 1/Lang-infected mice

While the in vitro properties of CD4(+) and CD8(+) cytokine-producing lymphocytes have been well studied, the in vivo cytokine production patterns and relative roles of CD4(+) and CD8(+) T lymphocytes during a primary in vivo immune response remain unclear. In this study, mice were inoculated intranasally with reovirus 1/L, and respiratory T lymphocyte populations were analyzed using multicolor flow cytometric analysis for the production of cytokine within and between classical type 1/type 2 patterns. Cytokine production observed in vivo following infection did not correlate with classical T cell cytokine expression patterns; instead, multiple types of lymphocyte populations that produced one of several possible cytokine combinations were present. Cytokine production by CD4(+) lymphocytes appears in the early and middle stages of the immune response, while CD8(+) lymphocytes produce more cytokine in the later stages. Early cytokine responses occurred predominantly in the whole lung and lung-associated lymph node populations. The complex patterns of cytokine expression seen in this study likely influence local cell-mediated immunity as well as the complex interaction of T cell subsets and the interaction of T cells with B cells which are necessary for the generation of cell-mediated and humoral immune responses required for effective broad-spectrum immunity.     

多发性硬化疾病及模型小鼠中疾病相关细胞因子和转录因子研究进展

多发性硬化症（multiple sclerosis,MS）是一种原发于中枢神经系统的炎症性脱髓鞘疾病。实验性自身免疫性脑脊髓炎（experimental autoimmune encephalomyelitis,EAE）与MS有相似的临床症状和病理特征,是被广泛应用于人类疾病研究的动物模型。MS确切的发病机制尚不清楚,但普遍认为是在易感基因的基础上,受环境因素触发,由CD4＋T细胞介导的中枢神经系统（centralnervous system,CNS）自身免疫性疾病。初始CD4＋T细胞在T细胞受体介导下活化,继而可分化为至少4个主要亚型,分别为TH1、TH2、TH17和iTreg细胞,参与不同类型的免疫应答。细胞因子和转录因子网络对CD4＋T细胞分化和效应细胞因子产物有重要意义。该文综述了各相关细胞因子和转录因子在CD4＋T细胞向不同亚型分化及MS/EAE发病过程中的相互作用和调控,揭示各因子在这些过程中的作用,有助于进一步研究和治疗MS。     

Two types of murine helper T cell clone. II. Delayed-type hypersensitivity is mediated by TH1 clones

We have previously shown that at least two types of Lyt-1+, Lyt-2-, L3T4+ helper T cell clones can be distinguished in vitro by different patterns of lymphokine secretion and by different forms of B cell help. Evidence is presented here to show that one type of helper T cell clone (TH1) causes delayed-type hypersensitivity (DTH) when injected with the appropriate antigen into the footpads of naive mice. The antigen-specific, major histocompatability complex (MHC)-restricted footpad swelling reaction peaked at approximately 24 hr. Footpad swelling was induced by all TH1 clones tested so far, including clones specific for soluble, particulate, or allogeneic antigens. In contrast, local transfer of TH2 cells and antigen did not produce a DTH reaction, even when supplemented with syngeneic spleen accessory cells. Similarly, local transfer of an alloreactive cytotoxic T lymphocyte clone into appropriate recipients did not produce DTH. The requirements for the DTH reaction induced by TH1 cells were investigated further by using TH1 clones with dual specificity for both foreign antigens and M1s antigens. Although these clones responded in vitro to either antigen + syngeneic presenting cells, or M1s disparate spleen cells, they responded in vivo only to antigen + MHC and did not cause footpad swelling in an M1s-disparate mouse in the absence of antigen. Moreover, in vitro preactivation of TH1 or TH2 cells with the lectin concanavalin A was insufficient to induce DTH reactions upon subsequent injection into footpads. From these results, we conclude that the lack of DTH given by TH2 clones in vivo could be due to the inability of the TH2 cells to produce the correct mediators of DTH, or to a lack of stimulation of TH2 clones in the footpad environment.     

The acute environment, rather than T cell subset pre-commitment, regulates expression of the human T cell cytokine amphiregulin

Cytokine expression patterns of T cells can be regulated by pre-commitment to stable effector phenotypes, further modification of moderately stable phenotypes, and quantitative changes in cytokine production in response to acute signals. We showed previously that the epidermal growth factor family member Amphiregulin is expressed by T cell receptor-activated mouse CD4 T cells, particularly Th2 cells, and helps eliminate helminth infection. Here we report a detailed analysis of the regulation of Amphiregulin expression by human T cell subsets. Signaling through the T cell receptor induced Amphiregulin expression by most or all T cell subsets in human peripheral blood, including naive and memory CD4 and CD8 T cells, Th1 and Th2 in vitro T cell lines, and subsets of memory CD4 T cells expressing several different chemokine receptors and cytokines. In these different T cell types, Amphiregulin synthesis was inhibited by an antagonist of protein kinase A, a downstream component of the cAMP signaling pathway, and enhanced by ligands that increased cAMP or directly activated protein kinase A. Prostaglandin E2 and adenosine, natural ligands that stimulate adenylyl cyclase activity, also enhanced Amphiregulin synthesis while reducing synthesis of most other cytokines. Thus, in contrast to mouse T cells, Amphiregulin synthesis by human T cells is regulated more by acute signals than pre-commitment of T cells to a particular cytokine pattern. This may be appropriate for a cytokine more involved in repair than attack functions during most inflammatory responses.     

A novel heterodimeric cytokine consisting of IL-17 and IL-17F regulates inflammatory responses

CD4＋ helper T （TH） cells play crucial roles in immune responses. Recently a novel subset of TH cells, termed THIL-17, TH 17 or inflammatory TH （THi）, has been identified as critical mediators of tissue inflammation. These cells produce IL-17 （also called IL-17A） and IL-17F, two most homologous cytokines sharing similar regulations. Here we report that when overexpressed in 293T cells, IL-17 and IL-17F form not only homodimers but also heterodimers, which we name as IL-17A/F. Fully differentiated mouse THi cells also naturally secrete IL-17A/F as well as IL-17 and IL-17F homodimeric cytokines. Recombinant IL-17A/F protein exhibits intermediate levels of potency in inducing IL-6 and KC （CXCL 1） as compared to homodimeric cytokines. IL-17A/F regulation of IL-6 and KC expression is dependent on IL-17RA and TRAF6. Thus, IL-17A/F cytokine represents another mechanism whereby T cells regulate inflammatory responses and may serve as a novel target for treating various immune-mediated diseases.     

Seasonal variations in cytokine expression and cell-mediated immunity in male rhesus monkeys

Our objectives in this study were to examine seasonal changes in immune responses including cytokine profiles of male rhesus monkeys housed under natural lighting conditions. We also monitored circannual changes in the secretion of several immunomodulatory hormones as potential mediators of the seasonal shifts in immune status. Retrospectively, the medical records of a large group of rhesus monkeys were examined to determine whether a common disease (campylobacteriosis) in this species shows a seasonal pattern of prevalence. Results of the study showed that there was a seasonal shift in the frequency of cells expressing TH1 cytokines (interleukin-2 and interferon-gamma) versus the TH2 prototype cytokine (interleukin-4) by peripheral blood mononuclear cells (PBMC) collected during the winter and summer. The frequency of TH1-type cytokine synthesis in the summer was markedly greater than in the winter whereas TH2-type cytokine expression did not vary between the two seasons. The proliferative response of PBMC to mitogens and natural killer cell activity of PBMC also varied with the season. Several hormones (testosterone, leptin, and prolactin) that modulate immune function exhibited circannual patterns of secretion. The prevalence of Campylobacter infections was higher in the spring than during the summer, fall, or winter. The data suggest that seasonal fluctuations in immune system status may alter the ability of primates to successfully respond to pathogens, and this may be related to circannual patterns of secretion of immunomodulatory hormones.     

Antigen-dependent cytokine mRNA expression by individual rhesus macaque T helper cells by flow cytometry

Specific patterns of cytokine secretion by CD4(+) T helper (Th) cells determine the nature of immune effector responses. Using a multiparameter, flow cytometric fluorescent in situ hybridization (FISH) assay that detected cytoplasmic mRNA within intact cells, we assessed antigen-specific cytokine expression in rhesus macaque Th cells. In the peripheral lymphocytes of immunized rhesus macaques, FISH detected antigen-induced cytokine gene expression in single Th cells. Analysis of simultaneous cytokine expression by single cells demonstrated that the recall immune response consisted of Th cells expressing either a Th1 (IL-2(+)/IFN-gamma(+)) or a Th2 (IL-4(+)/IL-6(+)) cytokine pattern. In addition to the classic Th subsets, Th cells expressing only one of two Th1 or Th2 defining cytokines were common following antigen restimulation. The data gathered with the FISH assay suggest that, in primates, the immune response to recall antigens consists of nonclassic Th cells, as well as a mixture of polarized Th1 and Th2 T cells.     

Interleukin-18: a regulator of cancer and autoimmune diseases

Interleukin (IL)-18, structurally similar to IL-1-, is a member of IL-1 superfamily of cytokines. This cytokine, which is expressed by many human lymphoid and nonlymphoid cells, has an important role in inflammatory processes. The main function of IL-18 is mediated through induction of interferon-γ (IFN-γ) secretion from T helper (Th1) cells. This cytokine synergistically with IL-12 contributes to Th1 differentiation and, therefore, is important in host defense mechanisms against intracellular bacteria, viruses, and fungi. Recent evidences showing the involvement of IL-18 in Th2 differentiation and ultimately IgE production from B cells have shed a new insight on the dual effects of IL-18 on Th1 and Th2 inflammatory responses. IL-18 in combination with IL-12 can activate cytotoxic T cells (CTLs), as well as natural killer (NK) cells, to produce IFN-γ and, therefore, may contribute to tumor immunity. The biological activity of IL-18 is not limited to these cells, but it also plays a role in development of Th17 cell responses. IL-18 synergistically with IL-23 can induce IL-17 secretion from Th17 cells. The diverse biological activity of IL-18 on T-cell subsets and other immune cells has made this cytokine a good target for investigating its role in various inflammatory-based diseases. Lately, the discovery of IL-18 binding protein (IL- 18BP), a physiological inhibitor of IL-18 and a hallmark of IL-18 biology, made this cytokine an attractive target for studying its pros and cons in the treatment of various diseases. In recent years, the biology, genetics, and pathological role of IL-18 have been studied in a number of diseases. In this article, we aimed to present an updated review on these aspects regarding the contribution of IL-18 to important diseases such as cancer, autoimmunity, and inflammatory-mediated conditions including allergic diseases, metabolic syndrome, and atherosclerosis. Emerging data indicating prognostic, diagnostic, and therapeutic features of IL-18 and its related molecules will also be discussed.     

A novel subset of helper T cells promotes immune responses by secreting GM-CSF

Helper T cells are crucial for maintaining proper immune responses. Yet, they have an undefined relationship with one of the most potent immune stimulatory cytokines, granulocyte macrophage-colony-stimulating factor (GM-CSF). By depleting major cytokines during the differentiation of CD4⁺ T cells in vitro, we derived cells that were found to produce large amounts of GM-CSF, but little of the cytokines produced by other helper T subsets. By their secretion of GM-CSF, this novel subset of helper T cells (which we have termed ThGM cells) promoted the production of cytokines by other T-cell subtypes, including type 1 helper T cell (Th1), type 2 helper T cell (Th2), type 1 cytotoxic T cell (Tc1), type 2 cytotoxic T cell (Tc2), and naive T cells, as evidenced by the fact that antibody neutralization of GM-CSF abolished this effect. ThGM cells were found to be highly prone to activation-induced cell death (AICD). Inhibitors of TRAIL or granzymes could not block AICD in ThGM cells, whereas inhibition of FasL/Fas interaction partially rescued ThGM cells from AICD. Thus, ThGM cells are a novel subpopulation of T helper cells that produce abundant GM-CSF, exhibit exquisite susceptibility to apoptosis, and therefore play a pivotal role in the regulation of the early stages of immune responses.     

Age-associated changes in interferon-γ and interleukin-4 secretion by purified human CD4+ and CD8+ T cells

Aging is associated with a decline in immune function. Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), two important immune deviation-related cytokines, are mainly produced by type 1 and type 2 T cells, respectively. To investigate the age-associated changes in the secretion of these two cytokines, 20 elderly and 20 young subjects fulfilling the SENIEUR protocol were enrolled. The ratios of CD4+ to CD8+ T cells were not different between the two age groups. The CD4+ and CD8+ T cells were purified by a magnetic cell sorting system, and then activated by concurrent anti-CD3 and anti-CD28 stimulation. The released cytokines were determined by ELISA. Both the CD4+ and the CD8+ T cells of the elderly individuals secreted a significantly larger amount of IFN-gamma after activation. Profound IL-4 production by CD8+ T cells was observed in the older subjects compared with that of the young subjects. These data suggested that age-associated decrease in immunity may be related to an imbalance in the secretion of immune deviation cytokines. The number of IL-4-secreting CD8+ T cells (T cytotoxic 2) rose significantly in the older individuals. Our design also provided a useful way to differentiate the T cell subsets secreting the same cytokine, such as IFN-gamma-producing T helper 1 and T cytotoxic 1 cells.     

Florence: cytokines and T-cell subsets.

The second international congress on cytokines, held in Florence (March 23-25, 1992), has been marked by the presentation of recent data about cytokine-deficient mice obtained by homologous recombination which, contrary to expectation, exhibit normal T and B cell development. The cloning of a few new cytokines and receptors were also reported as well as recent advances in the knowledge of the oldest members of this quickly growing family. The meeting has also been marked by a great number of reports providing insights into T cell-dependent immune response. Participants provided evidence, through their different experimental models, that functional T helper dichotomy, TH1 versus TH2, was of physiological relevance both in mice and humans, while other reports highlighted the differential regulation of these T lymphocytes subsets. An interesting discussion took place about their differentiation process and the harmonization of the concepts of naive, memory and effector T cells with the T subset classification according to cytokine production profile.     

IL-1 beta enhances CD40 ligand-mediated cytokine secretion by human dendritic cells (DC): a mechanism for T cell-independent DC activation.

CD40 ligand (CD40L) is a membrane-bound molecule expressed by activated T cells. CD40L potently induces dendritic cell (DC) maturation and IL-12p70 secretion and plays a critical role during T cell priming in the lymph nodes. IFN-gamma and IL-4 are required for CD40L-mediated cytokine secretion, suggesting that T cells are required for optimal CD40L activity. Because CD40L is rapidly up-regulated by non-T cells during inflammation, CD40 stimulation may also be important at the primary infection site. However, a role for T cells at the earliest stages of infection is unclear. The present study demonstrates that the innate immune cell-derived cytokine, IL-1beta, can increase CD40L-induced cytokine secretion by monocyte-derived DC, CD34(+)-derived DC, and peripheral blood DC independently of T cell-derived cytokines. Furthermore, IL-1beta is constitutively produced by monocyte-derived DC and monocytes, and is increased in response to intact Escherichia coli or CD40L, whereas neither CD34(+)-derived DC nor peripheral blood DC produce IL-1beta. Finally, DC activated with CD40L and IL-1beta induce higher levels of IFN-gamma secretion by T cells compared with DC activated with CD40L alone. Therefore, IL-1beta is the first non-T cell-derived cytokine identified that enhances CD40L-mediated activation of DC. The synergy between CD40L and IL-1beta highlights a potent, T cell-independent mechanism for DC activation during the earliest stages of inflammatory responses.     

Cytokine-modulated regulation of helper T cell populations

Helper T (Th) cells are a crucial component of the adaptive immune system and are of fundamental importance in orchestrating the appropriate response to pathogenic challenge. They fall into two broad categories defined by the cytokines each produces. Th1 cells produce interferon- gamma and are required for effective immunity to intracellular bacteria, viruses and protozoa whereas Th2 produce IL-4 and are required for optimal antibody production to T-dependent antigens. A great deal of experimental data on the regulation of Th1 and Th2 differentiation have been obtained but many essential features of this complex system are still not understood. Here we present a mathematical model of Th1/Th2 differentiation and cross regulation. We model Fas-mediated activation-induced cell death (AICD) as this process has been identified as an important mechanism for limiting clonal expansion and resolving T cell responses. We conclude that Th2 susceptibility to AICD is important for stabilizing the two polarized arms of the T helper response, and that cell-cell killing, not suicide, is the dominant mechanism for Fas-mediated death of Th1 effectors. We find that the combination of the anti-proliferative effect of the cytokine TGF- beta and the inhibiting influence of IL-10 on T cell activation are crucial controls for Th2 populations. We see that the strengths of the activation signals for each T helper cell subset, which are dependent on the antigen dose, co-stimulatory signals and the cytokine environment, critically determine the dominant helper subset. Switches from Th1- to Th2-dominance may be important in chronic infection and we show that this phenomenon can arise from differential AICD susceptibility of T helper subsets, and asymmetries in the nature of the cross-suppressive cytokine interactions. Our model suggests that in some senses a predominantly type 2 reaction may well be the "default" pathway for an antigen-specific immune response, due to these asymmetries.