Dietary glutamine supplementation modulates Th1/Th2 cytokine and interleukin-6 expressions in septic mice

Glutamine (Gln) has been demonstrated to have benefit in the modulation of systemic immunity in sepsis. However, the effects of Gln on local immunity and intra-lymphocyte cytokine expression have not been investigated in mice with gut-derived sepsis. This study evaluated the influence of a Gln-enriched diet on interleukin (IL)-6 expression in organs and Th1/Th2 type cytokine production within lymphocytes in septic mice. Male ICR mice were assigned to control and Gln groups. The control group was fed a semi-purified diet, while in the Gln group, Gln replaced part of the casein. After feeding the respective diets for 3 weeks, sepsis was induced by cecal ligation and puncture (CLP). Mice were sacrificed at 0, 6, 12 and 24h after CLP and their organs were harvested for further analysis. Results showed that IL-6 levels in the liver were decreased, whereas levels were increased in the lungs, kidneys and intestines with the progression of sepsis in both groups. Also, intra-lymphocyte interferon (IFN)-gamma expression decreased and IL-4 expression increased during sepsis. Compared to the control group, the Gln group had higher levels of IL-6 in the liver and lower levels in other organs at various time points. Lymphocyte IFN-gamma expression in the Gln group was higher, and IL-4 levels were lower than those of the control group after CLP. These results suggest that Gln supplementation decreased IL-6 production in non-hepatic organs, while reducing intra-lymphocyte IL-4 and enhancing IFN-gamma expressions. This change may reverse the Th2 type response to a more-balanced Th1/Th2 response during sepsis.     

Th17细胞及白细胞介素-17在肝移植急性排斥反应中的意义

目的探讨Th17细胞及相关因子白细胞介素-17（IL-17）在肝移植急性排斥反应中的变化及意义。方法收集2011年1月至2012年12月大连医科大学附属第二医院肝移植手术患者28例,根据移植肝组织穿刺活检病理诊断结果将肝移植的28例患者分为急性排异反应组6例和无排斥反应稳定组22例,15名健康体检者作为对照组。急性排斥组及稳定组在移植术后3 d和7 d,行肝穿刺活检病理检查;同时检测受检者外周血Th17细胞,受检者血清中IL-17水平。结果移植肝穿刺活检病理诊断显示急性排斥组随着移植时间延长,排斥反应逐渐增强。肝组织出现典型的细胞免疫性病理损伤,术后7 d肝脏汇管区、肝实质、小静脉壁、胆管上皮内及小叶间胆管被大量的淋巴细胞及嗜中性粒细胞包绕及浸润,胆管上皮细胞内空泡形成、上皮细胞凋亡。病理改变明显比术后3 d严重;急性排斥组患者术后3 d和7 d外周血Th17细胞比例及血清中IL-17含量较稳定组和对照组均明显增多（P〈0.05）,且Th17细胞及IL-17在术后急性排斥期7 d值均明显高于3 d（P〈0.05）。结论 Th17细胞及IL-17在肝移植急性排斥反应的发生、发展中可能起着促进作用,外周血Th17细胞及IL-17的检测有可能成为肝移植急性排斥反应的早期诊断指标。     

Alloreactive murine CD8+ T cell clones secrete the Th1 pattern of cytokines

A large panel of CD8+ mouse T cell clones expressed the cytokine synthesis pattern characteristic of Th1 clones. CD8+ clones synthesized IFN-gamma and lymphotoxin at levels similar to Th1 clones, whereas IL-2 was synthesized by only 50% of the clones and at significantly lower levels compared to Th1 clones. CD8+ clones also produced substantial amounts of granulocyte/macrophage-CSF, TY5, P500, and TNF-alpha which are expressed preferentially by Th1 clones and at lower levels by Th2 clones. The level of IL-3 produced by CD8+ clones was approximately 10% of that produced by Th1 and Th2 clones. Some CD8+ clones expressed low levels of the Th2-preferential product preproenkelphalin. None of the CD8+ clones expressed detectable levels of the Th2-specific products IL-4, IL-5, and P600, and the great majority did not express IL-6. The cytokine profile of CD8+ clones is representative of that secreted by activated normal CD8+ splenocytes, which includes IFN-gamma, low levels of IL-2 and IL-3 but no IL-4 or IL-5. Inasmuch as many Th1/Th2 functions are cytokine mediated, the striking similarity of the Th1 and CD8+ cytokine secretion patterns helps to explain why these two cell types share certain functions such as DTH, and also suggests that further common functions may be discovered in the future.     

Possible modulation by male sex hormone of Th1/Th2 function in protection against Plasmodium chabaudi chabaudi AS infection in mice

Zhang, Z.-H., Chen, L., Saito, S., Kanagawa, O., and Sendo, F. 2000. Possible modulation by male sex hormone of Th1/Th2 function in protection against Plasmodium chabaudi chabaudi AS infection in mice. Experimental Parasitology 96, 121-129. We examined the mortality, survival time, and parasitemia in interferon gamma receptor (IFN-gamma R)-deficient (IFN-gamma R(-/-)) and IL-4-deficient (IL-4(-/-)) mice infected with Plasmodium chabaudi AS and compared them with the wild type counterparts (IFN-gamma R(+/+) and IL-4(+/+), respectively). (1) Mortality was higher and survival time was shorter in males of both IFN-gamma R(-/-) and IL-4(-/-) mice infected with P. chabaudi AS, compared with their wild type counterparts, whereas such a difference was not observed in female mice. (2) These differences between males and females were not observed when male mice were castrated; however, female castration had no effect on the data. (3) The rate of parasitemia in both male and female IFN-gamma R(-/-) and IL-4(-/-) mice was higher at some points during the observation than in the wild type counterparts. (4) These results on susceptibility vs resistance to P. chabaudi AS infection can be explained partially by the levels of expression of Th1/Th2 cytokine and chemokine mRNAs in the spleen cells of the infected mice. These results suggest that male sex hormones modulate the function of Th1/Th2 cells and that these T cells counteract the activity of these hormones in protection against P. chabaudi AS infection in mice.     

Circulating Th1 and Th2 cytokines in patients with hepatitis C virus infection.

The imbalance of T-helper (Th) lymphocyte cytokine production may play an important role in immunopathogenesis of persistent hepatitis C virus (HCV) infection. To know whether an imbalance between Th1 and Th2 cytokines is present in chronic HCV infection, serum levels of Th1 cytokines, interferon gamma (IFN-gamma) and interleukin (IL)-2, and Th2 cytokines, IL-4 and IL-10, were measured using enzyme-linked immunosorbent assay in this study. Eighteen individuals with chronic HCV infection, 11 healthy subjects as normal controls and 10 chronic HBV infected patients as disease controls were observed. The results showed that the levels of Th2 cytokines (IL-4 and IL-10) were significantly increased in chronic HCV infected patients compared with normal controls (IL-4: 30.49+/-17.55 vs. 14.94+/-13.73, pg/ml, P<0.025; IL-10: 50.30+/-19.59 vs. 17.87+/-9.49, pg/ml, P<0.001). Similarly, the levels of Th1 cytokine, IL-2, was also elevated in individuals with chronic HCV infection when compared with normal controls (IL-2: 118.53+/-95.23 vs. 61.57+/-28.70, pg/ml, P<0.05). However, Th1 cytokine IFN-gamma level was not significantly changed during HCV infection (IFN-gamma: 28.09+/-15.65 vs. 24.10+/-15.61, pg/ml, P>0.05). Furthermore, the elevated levels of Th2 cytokines are greater than Th1 cytokines in HCV infection. Thus, the study indicates that an enhanced Th2 responses are present during chronic HCV infection, which may partly be responsible for the persistence of HCV infection.     

Egg deposition is the major stimulus for the production of Th2 cytokines in murine schistosomiasis mansoni.

To characterize Th cell populations induced by helminth infection, spleen cells from mice infected with Schistosoma mansoni were stimulated with parasite (worm or egg Ag) or mitogen (Con A) and the supernatants assayed for the Th1-specific cytokines IFN-gamma and IL-2 and the Th2-specific cytokines IL-4 and IL-5. Th2 cytokine production was not detected in substantial quantity until the 6 to 8th wk of infection and after reaching peak levels at 8 to 12 wk declined slowly thereafter. The time courses of IL-4 and IL-5 production, whereas differing from each other, closely resembled corresponding published data on IgE and peripheral blood eosinophil levels during murine schistosome infection. In contrast, Th1 cytokine responses occurred only during the first 6 wk of infection and were virtually absent during the peak period of Th2 production. To assess the role of egg deposition in the observed pattern of Th response, cytokine production was assayed in mice carrying unisexual schistosome infections in which parasite eggs are absent. Splenocytes from these animals displayed only marginal Th2 cytokine synthesis but greater Th1 cytokine responses than the corresponding cells from mice with bisexual infections. Moreover, cultures of liver tissue or isolated granulomas from infected mice constitutively produced high levels of IL-4 and IL-5 but failed to synthesize significant amounts of IL-2 and IFN-gamma even when stimulated with egg Ag or mitogen. Taken together the data indicate that egg deposition is the major stimulus of Th2 cytokine response in S. mansoni-infected mice and suggest that T cells belonging to this subset must play a major role in egg granuloma formation.     

Plasma levels of Th1 and Th2 cytokines in Ghanaian children with vaccine-modified measles

To understand the pathogenesis of vaccine-modified measles (VMM), we measured plasma levels of IFN-gamma and IL-2 (Th1 cytokines), IL-4 and IL-10 (Th2 cytokines), IL-12, TNF-alpha and TGF-beta1 in children with uncomplicated measles, who had anti-measles IgG antibodies and with a history of immunization on admission (day 0), day 14 and day 60. We compared these to levels in healthy, age-matched, immunized children. Plasma levels of IFN-gamma, IL-2 and IL-12 were significantly higher in VMM patients on day 0 compared to healthy controls (p = 0.023; p = 0.018; p = 0.001) respectively. In contrast, plasma IL-4 was lower in VMM patients on day 0 when compared to the controls (p = 0.009). Plasma levels of IL-12 remained consistently high on days 14 and 60 (p = 0.001; p = 0.04), whilst IL-10 levels fell significantly on the same days (p = 0.002; p = 0.001) respectively. Kinetically, IFN-gamma and IL-10 levels decreased consistently from day 0 to days 14 and 60 in VMM patients. In contrast, IL-4 levels increased from day 0 to day 14 and day 60. Our results therefore suggest that VMM is associated with an early up-regulation of Th1 cytokine production and a down-regulation of Th2 cytokine production. The strong Th1 response may be associated with the induction of IL-12 and memory cells, thus contributing to the early resolution of the infection and lack of complications.     

Changes in cytokine production of breast cancer patients treated with interferons

A clinical randomized study was performed on advanced breast cancer patients who were treated by interferons (IFN) beta and gamma in combination with hormonotherapy (Megace or Tamoxifen). Cytokine levels (IL-1beta, IL-2, IL-6, TNF-alpha, IFN-gamma) and sIL-2R of individual patients before, during (3 months) and after (6 months) therapy were evaluated and correlated to clinical response according to UICC criteria (responder patients-partial or Complete Response versus non-responder patients-Stable/Progression). Decreases in IL-1beta, IL-6 and sIL-2R were associated with clinical response to therapy versus increases in their levels which corresponded to progression of disease. A significant and dramatic increase in IFN-gamma levels was associated with a favourable response to therapy in the IFNs-treated patients, mainly in the group of Tamoxifen. Baseline levels of sIL-2R and of IFN-gamma were prognostic of clinical response and were found to be the most sensitive cytokine parameters for defining the clinical utility of the combination of IFNs and hormonotherapy in breast cancer patients.     

Intercellular adhesion molecule-1/LFA-1 ligation favors human Th1 development

Th cell polarization toward Th1 or Th2 cells is strongly driven by exogenous cytokines, in particular IL-12 or IL-4, if present during activation by Ag-presenting dendritic cells (DC). However, additional Th cell polarizing mechanisms are induced by the ligation of cell surface molecules on DC and naive Th cells. In the present study, the role of LFA-1/ICAM-1 ligation in human Th cell polarization was investigated. Triggering of LFA-1 on anti-CD3/CD28 stimulated naive Th cells with immobilized Fc-ICAM-1, in the absence of DC and exogenous cytokines, induced a marked shift toward Th1 cell development, accompanied by a dose-dependent decrease in GATA-3 expression and a dose-dependent increase in T-bet expression. Th1 polarization by LFA-1 ligation could be demonstrated only under low cytokine conditions, as it was largely overruled by IL-12 or IL-4. This IL-12-independent Th1-driving mechanism appears to be operated by certain subsets of effector DC. Maturation of DC by poly(I:C), a synthetic dsRNA, used as an in vitro model for viral infections, leads to the generation of Th1-driving effector DC (DC1), which express elevated levels of ICAM-1 but produce only low levels of IL-12p70. Blocking the ICAM-1/LFA-1 interaction in cocultures of these DC with naive Th cells attenuated their Th1-driving capacity. The molecular mechanism by which LFA-1 signaling supports Th1 differentiation is blocked by specific inhibitors of extracellular signal-regulated kinase phosphorylation. The present data indicate the existence of an IL-12-independent, extracellular signal-regulated kinase-mediated mechanism, through which high ICAM-1-expressing DC1 can drive Th1 polarization. This mechanism may be operational during viral infections.     

Single cell analysis reveals that IL-4 receptor/Stat6 signaling is not required for the in vivo or in vitro development of CD4+ lymphocytes with a Th2 cytokine profile

The concept that IL-4 is the primary signal for Th2 lymphocyte differentiation has recently been put in doubt by studies in which the production of Th2-associated cytokines was detected in mice deficient in IL-4 synthesis or IL-4R triggering. In this study, we formally demonstrate by single cell analysis that CD4+ lymphocytes with a classical Th2 phenotype (IL-4+, IL-5+, IFN-gamma-, IL-2-) develop in significant numbers in helminth-infected mice deficient in either IL-4R alpha-chain or Stat6. While an expanded population of Th1 (IL-4-, IL-5-, IFN-gamma+, IL-2+) lymphocytes was observed in the same animals, surprisingly, cells with a mixed Th0 cytokine pattern were rare. The cytokine production phenotypes of the Th1 and Th2 subpopulations generated in infected Stat6-deficient mice were unaffected by in vitro neutralization of endogenous IL-4 or IFN-gamma. Nevertheless, while addition of exogenous rIL-12 resulted in transitory IFN-gamma production by Th2 lymphocytes from both wild-type and Stat6-deficient mice, IL-4 synthesis was preserved in the former, but temporarily ablated in the latter cells. Importantly, IL-4+ IFN-gamma- and IL-4- IFN-gamma+ populations similar to those arising in helminth-infected Stat6-deficient mice could also be generated in vitro by repetitive polyclonal stimulation of CD4+CD62Lhigh lymphocytes from uninfected mice of the same strain. Together, the results of these single cell analysis experiments demonstrate that IL-4R/Stat6 signaling, while influencing the final frequency of Th2 lymphocytes, is not essential for Th2 cell development, and suggest that this pathway has a previously unrecognized function in stabilizing Th2 populations once they have emerged.     

Helicobacter pylori-induced mucosal inflammation is Th1 mediated and exacerbated in IL-4, but not IFN-gamma, gene-deficient mice

To elucidate the pathogenesis of Helicobacter pylori-associated gastritis, we studied immune responses of C57BL/6J wild-type (WT), SCID, and gene deficient (IFN-gamma-/- and IL-4-/-) mice following infection with a pathogenic isolate of H. pylori (SPM326). During early infection in WT mice, mononuclear and polymorphonuclear cells accumulated in the gastric lamina propria, and the numbers of cells in the inflamed mucosa expressing IFN-gamma, but not IL-4, mRNA rose significantly (p < 0.005), consistent with a local Th1 response. Splenic T cells from the same infected WT mice produced high levels of IFN-gamma, no detectable IL-4, and low amounts of IL-10 following in vitro H. pylori urease stimulation, reflecting a systemic Th1 response. Infected C57BL/6J SCID mice did not develop gastric inflammation despite colonization by many bacteria. Infected C57BL/10J and BALB/c mice also did not develop gastric inflammation and displayed a mixed Th1/Th2 splenic cytokine profile. These data imply a major role for the Th1 cytokine IFN-gamma in H. pylori-associated gastric inflammation in C57BL/6J mice. Compared with WT animals, infected IL-4-/- animals had more severe gastritis and higher levels of IFN-gamma production by urease-stimulated splenocytes (p < 0.01), whereas IFN-gamma-/- mice exhibited no gastric inflammation and higher levels of IL-4 production by stimulated splenocytes. These findings establish C57BL/6J mice as an important model for H. pylori infection and demonstrate that up-regulated production of IFN-gamma, in the absence of the opposing effects of IL-4 (and possibly IL-10), plays a pivotal role in promoting H. pylori-induced mucosal inflammation.     

Haptoglobin and the Th1/Th2 balance: hints from in vitro and in vivo studies

A variety of immunomodulatory effects have previously been attributed to haptoglobin (Hp). These are supposed to be partly mediated through binding of Hp to CD11b. In the present study, we assessed its effects on T-helper (Th) cytokine production following both in vitro and in vivo stimulation of T-cells. Hp exhibits a dose-dependent inhibitory effect on human T lymphocyte release of the Th2 cytokines (IL-4, IL-5, IL-10 and IL-13) in vitro, whereas it has no clear effect on Th1 cytokine (IL-2 and IFN-gamma) release. When administered an anti-CD3 monoclonal antibody, Hp knockout mice produced more IL-4 and less IFN-gamma than did their wild-type litter-mates. Our findings imply that Hp may be regarded as a regulator of the Th1/Th2 balance in both human and murine immune systems.     

Effects of liver-derived dendritic cell progenitors on Th1- and Th2-like cytokine responses in vitro and in vivo

There is evidence that donor-derived dendritic cells (DC), particularly those at a precursor/immature stage, may play a role in the immune privilege of liver allografts. Underlying mechanisms are poorly understood. We have examined the influence of in vitro generated mouse liver-derived DC progenitors (DCp) on proliferative, cytotoxic, and Th1/Th2 cytokine responses induced in allogeneic T cells. Liver DCp, propagated in GM-CSF from C57B10 mice (H2b), induced only minimal proliferation, and weak cytotoxic responses in allogeneic (C3H; H2k) T cells compared with mature bone marrow (BM)-derived DC. Flow-cytometric analysis of intracellular cytokine staining revealed that mature BM DC, but not liver DCp, elicited CD4+ T cell production of IFN-gamma. Intracellular expression of IL-10 was very low in both BM DC- and liver DCp-stimulated CD4+ T cells. Only stimulation by liver DCp was associated with IL-10 secretion in primary MLR. Notably, these liver DCp cocultured with allogeneic T cells stained strongly for IL-10. Following local (s.c. ) injection in allogeneic recipients, both BM DC and liver DCp homed to T cell areas of draining lymph nodes and spleen, where they were readily detected by immunohistochemistry up to 2 wk postinjection. Liver DCp induced clusters of IL-10- and IL-4-secreting mononuclear cells, whereas Th2 cytokine-secreting cells were not detected in mice injected with mature BM DC. By contrast, comparatively high numbers of IFN-gamma+ cells were induced by BM DC. Modulation of Th2 cytokine production by donor-derived DCp may contribute to the comparative immune privilege of hepatic allografts.     

Characterization of accessory cell costimulation of Th1 cytokine synthesis.

We studied the capacity of macrophage and B cell lines to provide a costimulatory signal that enhances synthesis of IFN-gamma and IL-2 by mouse Th1 clones stimulated with suboptimal doses of immobilized anti-CD3 antibody. The J774 macrophage line and the CH27 B lymphoma line had the greatest costimulatory activity and routinely increased IL-2 production by 10-fold to 100-fold. Other macrophage and B cell lines had less activity and T cell lines were unable to costimulate. The J774 and CH27 lines did not costimulate IL-4 production by a Th2 clone and had only a small effect on IL-2 production by T cell hybridomas. The process of costimulation was fixation-sensitive, contact-dependent and did not involve stable cytokines present in the T cell/accessory cell conditioned media. Neutralizing antibodies for IL-1, IL-6, and TNF failed to inhibit costimulation. Antibodies to the LFA-1/ICAM-1 pair of adhesion molecules also failed to inhibit. Costimulation of IL-2 production by accessory cells was found to have a unidirectional species restriction: mouse accessory cells costimulated mouse and human IL-2-producing T cells, but human U937 cells induced with PMA were effective only for human T cells. The results indicate that accessory cells can significantly regulate Th1 effector function at the level of cytokine production.     

Paradoxical roles of IFN-gamma in models of Th1-mediated autoimmunity

T-cell responses to antigens are classified on the basis of the cytokines they produce as either Th1 (IFN-gamma, IL-2) or Th2 (IL-4, IL-10), with these Th types being indicative of either cell-mediated or antibody-mediated responses, respectively. Using this classification, T-cell responses in MHC-class-II-restricted autoimmune diseases appear to be predominantly of the Th1 type, based on the presence of high levels of IFN-gamma. This simplistic classification has recently been challenged, however, as disease incidence and severity are frequently elevated in animals that have a deficient IFN-gamma response. The recent data discussed here indicate that the cytokine circuits involved in the regulation of cell-mediated and humoral immune responses during the development of autoimmune arthritis are more complex than originally proposed; perhaps our characterization of autoimmune responses as strictly Th1 or Th2 is overly simplistic, especially as it pertains to the role of IFN-gamma.     

Synergistic effect of IL-2, IL-12, and IL-18 on thymocyte apoptosis and Th1/Th2 cytokine expression

In the periphery, IL-18 synergistically induces the expression of the Th1 cytokine IFN-gamma in the presence of IL-12 and the Th2 cytokines IL-5 and IL-13 in the presence of IL-2. Although the expression of these cytokines has been described in the thymus, their role in thymic development and function remains uncertain. We report here that freshly isolated thymocytes from C57BL/6 and BALB/c mice stimulated in vitro with IL-2-plus-IL-18 or IL-12-plus-IL-18 produce large amounts of IFN-gamma and IL-13. Analysis of the thymic subsets, CD4(-)CD8(-) (DN), CD4(+)CD8(+), CD4(+)CD8(-), and CD4(-)CD8(+) revealed that IL-18 in combination with IL-2 or IL-12 induces IFN-gamma and IL-13 preferentially from DN cells. Moreover, DN2 and DN3 thymocytes contained more IFN-gamma(+) cells than cells in the later stage of maturation. Additionally, IL-18 in combination with IL-2 induces CCR4 (Th2-associated) and CCR5 (Th1-associated) gene expression. In contrast, IL-18-plus-IL-12 specifically induced CCR5 expression. The IL-2-plus-IL-18 or IL-12-plus-IL-18 effect on IFN-gamma and IL-13 expression is dependent on Stat4 and NF-kappaB but independent of Stat6, T-bet, or NFAT. Furthermore, IL-12-plus-IL-18 induces significant thymocyte apoptosis when expressed in vivo or in vitro, and this effect is exacerbated in the absence of IFN-gamma. IL-12-plus-IL-18-stimulated thymocytes can also induce IA-IE expression on cortical and medullary thymic epithelial cells in an IFN-gamma-dependent manner. Thus, the combination of IL-2, IL-12, and IL-18 can induce phenotypic and functional changes in thymocytes that may alter migration, differentiation, and cell death of immature T cells inside the thymus and potentially affect the Th1/Th2 bias in peripheral immune compartments.