Jak3 negatively regulates dendritic-cell cytokine production and survival

Cytokines are critical in regulating the development and function of diverse cells. Janus kinase 3 (Jak3) is a tyrosine kinase expressed in hematopoietic cells that associates with the common gamma chain (gammac) and is required for signaling for a family of cytokines including interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21; deficiency of either Jak3 or gammac results in severe combined immunodeficiency (SCID). While Jak3 is essential for lymphoid-cell development, the potential roles for Jak3 in regulating dendritic cells (DCs) were unclear. Herein, we show that although CD8+CD11c+ splenic DCs are absent in Jak3-/- mice, bone marrow-derived DCs developed normally in vitro from Jak3-/- precursor cells. In fact, the survival of Jak3-/- DCs was enhanced, and they expressed lower levels of proapoptotic proteins. Jak3-/- DCs exhibited normal antigen uptake and up-regulation of costimulatory molecules. However, Jak3-/- DCs produced more IL-12 and IL-10 in response to Toll-like receptor ligands, which correlated with enhanced T helper 1 (Th1) differentiation in vivo. In summary, Jak3 is not essential for DC development but unexpectedly appears to be an important negative regulator. These results may be relevant clinically for patients with SCID who have undergone hematopoietic stem cell transplantation and for patients who might be treated with a Jak3 inhibitor.     

Th1 and Th2 cytokine profiles in sickle cell disease

We have investigated the levels of Th1 (IL-2 and IFN-gamma) and Th2 (IL-4) cytokines in the plasma and supernatants following peripheral blood mononuclear cell culture and mitogen stimulation in a group of 39 patients with sickle cell disease (SCD) made up of 29 SS, 8 Sbeta-thal and 2 Hb SD in steady state. Five SS patients were studied during 7 episodes of vaso-occlusive crisis. Twenty-four control (3 Hb AS and 21 Hb AA) were also studied; 10 were acutely ill while 14 were healthy at the time of the study. The plasma levels of IL-2 and IFN-gamma were similar in the patients and the controls. However, plasma IL-4 was significantly higher among the steady-state SS patients than in the controls. While there was no significant difference in cytokine levels following mitogen stimulation in the different groups, plasma IL-2 to IL-4 and IFN-gamma to IL-4 ratios were significantly lower among the steady-state SS patients, indicating a possible Th2 bias in our sickle cell patients and suggesting a possible mechanism to explain the predisposition of SCD patients to bacterial infections. However, SS patients with good splenic function showed a relative Th1 bias, which may be an additional explanation for the protection against bacterial infections in such patients.     

IL-1 family members and STAT activators induce cytokine production by Th2, Th17, and Th1 cells

Expression of T1ST2, the IL-33R, by Th2 cells requires GATA3. Resting Th2 cells express little GATA3, which is increased by IL-33 and a STAT5 activator, in turn increasing T1ST2 from its low-level expression on resting Th2 cells. Th2 cells that have upregulated T1ST2 produce IL-13, but not IL-4, in response to IL-33 plus a STAT5 activator in an antigen-independent, NF-κB-dependent, cyclosporin A (CsA)-resistant manner. Similarly, Th17 cells produce IL-17A in response to IL-1β and a STAT3 activator and Th1 cells produce IFNγ in response to IL-18 and a STAT4 inducer. Thus, each effector Th cell produces cytokines without antigenic stimulation in response to an IL-1 family member and a specific STAT activator, implying an innate mechanism through which memory CD4 T cells are recruited by an induced cytokine environment.     

Lactobacillus Acidophilus strain L-92 regulates the production of Th1 cytokine as well as Th2 cytokines.

BACKGROUND: There is growing interest in probiotics such as lactic acid bacteria (LAB), not only for treatment of T helper type (Th) 1-mediated diseases but also for Th2-mediated diseases, including allergic diseases, since lactic acid bacteria may be able to modulate the Th1/Th2 balance, in addition to having an immunomodulative effect through induction of Th1 bias. METHODS: The effect of oral administration of heat-killed Lactobacillus acidophilus Strain L-92 (L-92) on ovalbumin (OVA)-specific immunoglobulin (Ig)E production was investigated in BALB/c mice. L-92 was orally administered to mice for 8 weeks from 2 weeks after initiation of OVA-immunization. Patterns of cytokine and Ig production in splenocytes and cells from Peyer's patches (PPs) from these mice were examined after restimulation with OVA in vitro. RESULTS: L-92 significantly suppressed serum OVA-specific IgE levels for a long period. Cytokines such as interferon (IFN)-gamma, interleukin (IL)-4 and IL-10 and Igs such as total IgE and OVA-specific IgE were produced at significantly lower levels by splenocytes of L-92-treated mice, compared with those of control mice. In contrast, transforming growth factor (TGF)-beta and IgA levels produced by PPs from L-92-treated mice were significantly higher than in those from control mice. CONCLUSIONS: Oral L-92 administration regulated both Th1 and Th2 cytokine responses, suppressed serum OVA-specific IgE, and induced TGF-beta production in PPs. TGF-beta is known to be associated with activation of regulatory T (Treg) cells. These data suggest that LAB may have immunomodulative effect by Treg cells via TGF-beta activity.     

Frequency of clonal intraepithelial T lymphocyte proliferations in enteropathy-type intestinal T cell lymphoma, coeliac disease, and refractory sprue

BACKGROUND: Clonal T cell receptor (TCR) gene rearrangements and loss of T cell antigens such as CD8 and TCR-beta in intraepithelial lymphocytes (IELs) may indicate the development of an enteropathy-type intestinal T cell lymphoma (EITCL) in patients with refractory sprue. AIMS: To define the diagnostic value of these markers in duodenal biopsies from patients with villous atrophy as a result of various underlying disorders. PATIENTS AND METHODS: Duodenal biopsies from eight patients with coeliac disease and five patients with villous atrophy caused by defined disorders were compared with three patients with refractory sprue evolving into overt EITCL, two patients with ulcerative jejunitis, and with eight patients with overt EITCL, for expression of CD3, CD4, CD8, and TCR-beta in IELs using immunohistochemistry and for clonal TCR-gamma gene rearrangements using polymerase chain reaction. In addition, biopsies from six consecutive patients with refractory sprue of uncertain cause were examined. RESULTS: Clonal TCR-gamma gene rearrangements were found in all resected tumours of patients with EITCL, in 3/8 duodenal biopsies of patients with EITCL, in 2/2 patients with ulcerative jejunitis, in 2/3 patients with refractory sprue evolving into overt EITCL, and in 1/6 patients with refractory sprue. No rearrangements were found in biopsies from patients with refractory sprue caused by defined disorders or those with coeliac disease. Clonality in duodenal biopsies was associated with an abnormal phenotype of IELs in all cases and in all but one case in patients with evidence of underlying coeliac disease. Specificity for detection of an EITCL using immunohistology was 77% for CD8 and for TCR-beta staining, and 100% for detection of a clonal TCR-gamma gene rearrangement. Sensitivity was 62% for staining with CD8 and clonality investigation, while sensitivity reached 100% for TCR-beta staining in all investigated patients with EITCL. CONCLUSIONS: Clonal proliferations of phenotypically abnormal IELs in refractory sprue represent an early manifestation of EITCL, for which the term "sprue-like intestinal T cell lymphoma" is proposed. This constellation is also found in duodenal biopsies from patients with an overt EITCL and is not related to other sprue syndromes, resulting in a high specificity for detection of an EITCL or refractory sprue evolving into EITCL. Overt EITCL may develop directly from coeliac disease without a precursor lesion (refractory sprue with clonal IELs) being demonstrable in duodenal biopsies or via a "sprue-like intestinal T cell lymphoma". This latter entity is a complication of coeliac disease.     

Enhanced monocyte Th1 cytokine production in HCV-infected cryoglobulinemic patients

BACKGROUND/AIMS: The etiologic link between chronic hepatitis C virus (HCV) infection and mixed cryoglobulinemia is well established, while its prognostic significance within the context of HCV-related hepatitis is not as clear. Patients with an HCV-related cryoglobulinemic syndrome oft have mild liver disease, an aspect that can be influenced by an individual's Th1/Th2 orientation. Our goal was to document stigmata of differentiate cytokine production in this subgroup of patients. METHODS: Fifteen patients with chronic HCV-related liver disease (CLD) and a cryoglobulinemic syndrome (CRYO) were compared to age/sex matched CLD controls with negative cryocrit. Cultured monocytes were stimulated with either Staphylococcus aureus (SAC) or lipopolysaccharide (LPS). RESULTS: The protein concentrations of TNF-alpha and of the Th1-type cytokines interleukin (IL)-12 and IL-18 were significantly greater in the CRYO group, while IL-10 (a Th2 cytokine) levels were greater in the control group. CONCLUSIONS: The clinical distinctiveness of the two groups was reflected at the cytokine level. The cryoglobulinemic patients studied showed a greater Th1 polarization than their cryoglobulin-negative counterparts. This enhanced production of Th1-type cytokines is seemingly not able to rid the host of infection but may account for a milder course of liver disease.     

Jejunal biopsy and lymphocyte co-culture in coeliac disease

Jejunal biopsies from 13 patients with treated coeliac disease were maintained in organ culture for 24 h with and without the addition of gluten fraction III, in each case with and without autologous peripheral blood mononuclear cells. Biopsies cultured with gluten alone or with lymphocytes alone showed no significant reduction in mean enterocyte height compared with those cultured in control medium, but those cultured with both gluten and lymphocytes had significantly lower enterocyte height than control biopsies, than those cultured with gluten alone, and than those cultured with lymphocytes alone. These results demonstrate that the combination of gluten and lymphocytes is more toxic to treated coeliac mucosa in vitro than either one alone and support the suggestion that immune reactions to gluten may be important in the pathogenesis of the mucosal lesion of coeliac disease.     

Interleukin 15: a key to disrupted intraepithelial lymphocyte homeostasis and lymphomagenesis in celiac disease

BACKGROUND & AIMS: The mechanism of intraepithelial lymphocyte hyperplasia, a hallmark of celiac disease, is unknown. We have investigated the role of epithelium-derived interleukin (IL)-15 in the alterations of epithelial homeostasis in refractory celiac sprue, a privileged situation to study the first step of lymphoid transformation and the contribution of intraepithelial lymphocytes to villous atrophy in celiac disease. METHODS: IL-15 expression was assessed in biopsy specimens and isolated enterocytes by combining immunohistochemistry, flow cytometry, and real-time quantitative polymerase chain reaction. The ability of IL-15 to induce growth and survival of clonal intraepithelial lymphocytes lacking surface CD3 and to induce their cytotoxicity and secretion of interferon gamma was tested using soluble IL-15 and coculture in the presence of epithelial cell lines expressing membrane IL-15. RESULTS: IL-15 was massively overexpressed not only in lamina propria but also in the intestinal epithelium of patients with active celiac disease and refractory celiac sprue. IL-15 was not secreted but delivered at the surface of enterocytes. IL-15 specifically induced the expansion and survival of the clonal abnormal intraepithelial lymphocytes that characterize refractory celiac sprue and triggered their secretion of interferon gamma and their cytotoxicity against intestinal epithelial cells. Comparable activating signals could be delivered by IL-15 expressed at the membrane of the T84 enterocyte cell line. CONCLUSIONS: These data provide strong evidence that uncontrolled overexpression of IL-15 in refractory celiac sprue perpetuates epithelial damage and promotes the emergence of T-cell clonal proliferations. Blocking IL-15 might prove useful to treat this severe complication of celiac disease.     

Dominant Th1 cytokine production in early onset of human brucellosis followed by switching towards Th2 along prolongation of disease

Human brucellosis is a worldwide zoonotic infectious disease which is caused by intracellular bacteria belonging to the genus Brucella. Based on murine studies it has been shown that host resistance to Brucella depends on Th1 response, whereas Th2 response is involved in the severity of the disease. Since the immune response during human brucellosis has not been profoundly studied we have tried to evaluate cytokine production in patients suffering from brucellosis. Diluted whole blood samples were cultured in the presence of the mitogen, heat inactivated bacteria or medium alone. IL-12, IFN-gamma and IL-10 were measured by specific sandwich ELISA. In addition, the percentage of CD3(+) T cells producing either IL-13 or IFN-gamma was determined by flow cytometry. It was found that not only IFN-gamma production but also the number of CD3(+) IFN-gamma-producing cells decreased with prolongation of the disease but the percentage of CD3(+) IL-13(+) T cells were significantly increased. No correlation between duration of disease and IL-10 or IL-12 production was found. In conclusion, it is proposed that at the onset of brucellosis, Th1 response dominates while diminishing with prolongation of the disease.     

Interferon-gamma, a Th1 cytokine, regulates fat inflammation: a role for adaptive immunity in obesity

Adipose tissue (AT) can accumulate macrophages and secrete several inflammatory mediators. Despite its pivotal role in the progression of chronic inflammatory processes such as atherosclerosis, the adaptive role of immunity in obesity remains poorly explored. Visceral AT of diet-induced obese C57BL/6 mice had higher numbers of both CD4(+) and CD8(+) T cells than lean controls, monitored by flow cytometry. When stimulated in vitro, T cells from obese AT produced more interferon (IFN)gamma than those from controls. AT from obese animals also had more cells expressing I-A(b), a mouse class II histocompatibility marker implicated in antigen presentation, as determined by immunostaining. Differentiated 3T3-L1 cells stimulated with recombinant IFNgamma or T-helper 1-derived supernatant produced several chemokines and their mRNAs. Obese IFNgamma-deficient animals had significantly reduced AT expression of mRNA-encoding inflammatory genes such as tumor necrosis factor-alpha and monocyte chemoattractant protein-1, decreased AT inflammatory cell accumulation, and better glucose tolerance than control animals consuming the same diet. Obese mice doubly deficient for IFNgamma receptor and apolipoprotein (Apo)E on a mixed 129SvEv/C57BL/6 (129/B6) genetic background, despite exhibiting similar AT mRNA levels of tumor necrosis factor-alpha and monocyte chemoattractant protein-1 as 129/B6-ApoE(-/-) controls, had decreased expression of important T cell-related genes, such as IFNgamma-inducible protein-10 and I-A(b), and lower plasma triglycerides and glucose. These results indicate a role for T cells and IFNgamma, a prototypical T-helper 1 cytokine, in regulation of the inflammatory response that accompanies obesity.     

白细胞介素12调节小鼠Th1/Th2的抗结核分支杆菌感染研究

目的 观察、评价白细胞介素１２（ＩＬ－１２）对结核分支杆菌感染小鼠细胞因子的影响和疗效。方法 将ＢＡＬＢ／ｃ小鼠４２只,制成小鼠结核分支杆菌感染模型,随机分为对照组（ＰＢＳ）和ＩＬ－１２共两组（２１只）。给予ＰＢＳ或ＩＬ－１２治疗,检测血清γ干扰素（ＩＮＦ－γ）、ＩＬ－４、ＩＬ－１０水平（ＥＬＩＳＡ法）和器官菌数计数,观察治疗后生存率。结果 ＩＬ－１２组小鼠无一死亡、肺、肝、脾菌落数分别为（２２７     

Effects of Th1 and Th2 cytokines on cytokine production and ICAM-1 expression on synovial fibroblasts.

OBJECTIVES--To investigate the influence of the Th1 and Th2 lymphokines interleukins (IL)-4 and IL-13, interferon gamma (IFN gamma), and several monokines on the adhesion of mononuclear cells to synovial fibroblasts and intercellular adhesion molecule-1 (ICAM-1) expression and cytokine production of synovial fibroblasts in patients with osteoarthritis. METHODS--Synovial fibroblasts were isolated from patients with osteoarthritis and stimulated with IL-1 beta, IL-4, IL-6, IL-10, IL-12, IL-13, tumour necrosis factor alpha (TNF alpha), and IFN gamma. Subsequently, we determined the production of IL-1 alpha, IL-1 beta, IL-6, IL-10, IL-12, IFN alpha and TNF alpha, and the expression of ICAM-1 lymphocyte function associated antigen 3 (LFA-3), BB7, and major histocompatibility complex class II molecules on these cells. Furthermore, the adhesion of freshly isolated mononuclear cells from the peripheral blood was tested using a colourimetric cell-cell adhesion assay. RESULTS--Only production of IL-6 and the expression of ICAM-1 were observed. IL-1 beta and TNF alpha were the most potent stimulatory mediators of both cytokine production and ICAM-1 expression. IL-4 and IL-13 had differential effects as they upregulated cytokine production but downregulated IFN gamma induced ICAM-1 expression. In functional adhesion assays, TNF alpha, IL-1 alpha and, to a lesser extent, IFN gamma led to increased adhesion of mononuclear cells, whereas IL-4 and IL-13 had no effect. CONCLUSIONS--Our data indicate that Th1 and Th2 lymphokines can modulate the function (cytokine production and expression of adhesion molecules) of synovial fibroblasts.     

Changes in intraepithelial lymphocyte subpopulations in coeliac disease and enteropathy associated T cell lymphoma (malignant histiocytosis of the intestine).

Studies of the morphologic and phenotypic diversity of intraepithelial T cells in human small intestine have shown them to be heterogeneous, yet distinct from most extra intestinal T cells. In this study sequential immunoenzymatic staining was used to define new intraepithelial lymphocyte subpopulations in man. In normal human jejunum approximately 6% of the intraepithelial T cells expressing CD3 (an antigen associated with the T cell receptor) do not express the T cell subset antigens CD4 or CD8. Approximately 20% of CD7+ cells (T cells and null cells) do not express CD4 or CD8 and 14% of the CD7+ cells do not express CD3 and are therefore not T cells. The CD7+, CD3+/-, CD4-, CD8- population is concentrated in the tips of the villi. In coeliac disease, the ratios of the subsets change significantly. The percentage of CD3+, 4-, 8- cells increases to 28%, the proportion of CD7+, 4-, 8- cells remains unchanged and the CD7+, CD3- (non-T cell) population is reduced to 1.4% of the CD7+ cells. In contrast, in patients with villous atrophy of uncertain aetiology, all CD4-, CD8- lymphocyte subsets are decreased compared with normal biopsies. Finally, in enteropathy associated T cell lymphoma (malignant histiocytosis of the intestine) in which the 'uninvolved mucosa' is histologically similar to untreated coeliac disease, the changes in the intraepithelial T cell sub-sets are indistinguishable from those in coeliac disease, suggesting that the lymphoma is a complication of coeliac disease.     

Impaired Th1 cytokine production in spondyloarthropathy is restored by anti-TNFα

OBJECTIVES: To evaluate the effect of anti-TNFalpha on the Th1 and Th2 cytokines in patients with spondyloarthropathy (SpA). METHODS: Peripheral blood mononuclear cells (PBMC) were obtained from 20 patients with active SpA treated with infliximab (5 mg/kg). For comparison, PBMC were also obtained from 15 healthy controls and 19 patients with active rheumatoid arthritis (RA). After stimulation with PMA/ionomycin, the intracellular cytokines interleukin (IL)2, IL4, IL10, and interferon (IFN)gamma were determined in CD3+ T cells and in CD3+/CD56+ natural killer (NK) T cells by flow cytometry. RESULTS: At baseline the percentage of T cells positive for IFNgamma (p=0.020) and IL2 (p=0.046) was decreased in patients with SpA compared with healthy controls, while IL10 (p=0.001) was increased. This cytokine profile, confirmed by the mean fluorescence intensities (MFI), was more pronounced in CD3+/CD8- cells and contrasted with higher IL2 production in RA. NK T cells, characterised by high IL4 and IL10 numbers, were also increased in patients with SpA (p=0.017). Treatment with infliximab induced a significant and persistent increase in IFNgamma and IL2 in patients with SpA. Moreover, there was a transient decrease in IL10 and NK T cells in patients with high baseline values, resulting in values comparable with those of healthy controls. This switch in cytokine profile was seen in both the CD3+/CD8- and CD3+/CD8+ subsets. CONCLUSIONS: Before treatment patients with SpA had an impaired Th1 cytokine profile compared with healthy controls and patients with RA. TNFalpha blockade induced restoration of the Th1 cytokines, resulting in a normal cytokine balance. These data confirm the effect of anti-TNFalpha on the immune changes in SpA, and provide insights into the mechanisms involved in TNFalpha blockade.     

Effects of interferon and ribavirin combination therapy on CD4+ proliferation, lymphocyte activation, and Th1 and Th2 cytokine profiles in chronic hepatitis C

We studied the relationship between immunological markers such as CD4+ proliferation, cytokines profile and lymphocyte activation markers in patients with chronic hepatitis C, having different responses to interferon (IFN) and ribavirin (RBV) treatment. A prospective study of 20 patients was conducted, six had received IFN-alpha-2b alone and 14 IFN in combination with RBV. The proliferative immune responses of peripheral blood mononuclear cells to hepatitis C virus peptides and the lymphocyte activation markers (CD25+, CD38+ and CD69+) were assessed before treatment, at 1 week, and 1, 3 and 6 months of treatment. Cytokines interleukin (IL)-2, IFN-gamma, IL-4 and IL-10 were determined in supernatants before onset of treatment and at 1 and 6 months thereafter. Stimulation indices (SI) were higher in the sustained responders (SR), in comparison with those with no response (NR), before treatment (5.2 +/- 3.7 to 3.3 +/- 1.9, P = 0.028) and also at 6 months (7.8 +/- 1.9 to 4.1 +/- 1.2, P = 0.021). Patients with SR also had high SI to NS3 when compared with those with transitory response or no response (NR) (4.9 +/- 2.5 and 3.3 +/- 1.1, P = 0.033). At 1 month, SR had higher supernatant IL-2 than those with NR (133.8 +/- 119.2 to 56.0 +/- 89.3 pg/mL, P = 0.023) and lower levels of IL-10 (13.8 +/- 10.1 and 167.1 +/- 272.0 pg/mL, P = 0.023) in response to NS3. Combination therapy induced a higher percentage of the lymphocyte activation markers CD69+ and CD38+. In conclusion, we found that SR is associated with higher CD4+ proliferation particularly in response to the NS3 region, promoting a T-helper (Th)1/Th0 profile of cytokines, and that combination therapy induced a higher percentage of lymphocyte activation than therapy with IFN alone.