Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:BIOD00017 (IFN-gamma)
 28,919 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The IgA effector sites such as the salivary glands and the intestinal tract contain several distinct T cell subsets which possess unique biologic characteristics. Freshly isolated CD3+ T cells from the salivary glands, the LP region of the small intestine and IELs all harbor T cells which spontaneously produce Th1 (IFN-gamma)- and Th2 (IL-5 and IL-6)-type cytokines. Interestingly, a high frequency of IL-5-producing Th2-type cells is always associated with the occurrence of increased numbers of IgA plasma cells (e.g., the salivary glands and the LP region of the small intestine). Further, the salivary gland CD3+ T cells can be divided into three distinct subsets including those of CD4+, CD8- (12-23%), CD4-, CD8+ (18-25%) and DN (6-16%) T cells. In terms of TCR expression, CD4+, CD8- and DN T cells exclusively expressed alpha/beta TCR and gamma/delta TCR, respectively. One of the unique features of the salivary gland T cells is that like IELs, relatively high numbers of gamma/delta TCR-bearing cells are seen in the CD4-, CD8+ T cell fraction. Since our study has provided important new evidence that these gamma/delta TCR-bearing T cells from IELs of mice orally immunized with TD antigen possess the capability of abrogating oral tolerance to antigen-specific immune responses including the IgA isotype, one can visualize that gamma/delta TCR+ T cells can be essential regulatory T cells which protect (or enhance) alpha/beta TCR+, CD4+ Th cells for maximum IgA responses at IgA effector tissues including the salivary glands, and the gastrointestinal tract in the presence of an active state of systemic unresponsiveness or oral tolerance.
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PMID:Cytokine production and T cell receptor expression by salivary gland T cells and intraepithelial T lymphocytes for the regulation of the IgA response. 129 32

The effects of an anti-CD3 mAb on induction of non-MHC restricted cytolysis was investigated. Peripheral blood mononuclear cells (PBMC) from normal donors (29) and cancer patients (18) were cultured in 100 U/ml of interleukin-2 (rIL-2) with and without anti-CD3 mAb (OKT3, 10 ng/ml) for the first 48 hours of incubation. Thereafter, both PBMC cultures were maintained on rIL-2 up to 20 days. PBMC proliferation was enhanced 17-fold in number by day 20 when anti-CD3 mAb and rIL-2 was present during the first 48 hours but only 3-fold by day 20 when rIL-2 alone was present. Concomitantly anti-CD3 mAb but not Lym-1, an isotype matched control, inhibited the induction of lytic activity against both NK sensitive (K562) and NK resistant (Raji) target cell lines. Thus the inhibitory effect is dependent on anti-CD3 mAb stimulating the CD3/TCR T-cell receptor complex. While lytic activity was dependent on the concentration of rIL-2, inhibition of the induction phase of non-MHC restricted lytic activity was independent of the concentration of rIL-2. Flow cytometry analysis indicated that treatment with the anti-CD3 mAb increased the percentage of CD3 positive cells, CD4 positive cells and especially CD25 positive cells, but decreased th percentage of CD56 positive cells. Supernatants from anti-CD3 mAb stimulated cultures also inhibited the induction of non-MHC restricted lytic activity. Lymphokine analysis showed that supernatants of anti-CD3 mAb stimulated cultures had higher levels of TNF-alpha and IFN-gamma. However, TNF-alpha and IFN-gamma alone or in combination could not mediate the inhibitory effect. The inhibitory factor(s) was partially purified by sequential chromatography on matrices of controlled pore glass and Sepharose CL-6B. The molecular weight of the inhibitory factor(s) was less than 67K. These studies have identified a novel regulatory pathway controlling non-MHC restricted cytolysis. Perturbation of the T-cell CD3/TCR complex with the anti-CD3 mAb results in the secretion of a soluble mediator that down-regulates the induction of rIL-2 dependent non-MHC restricted cytolysis.
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PMID:The effect of anti-CD3 on the induction of non-MHC restricted cytolytic activity. 129 40

To characterize the requirements for the induction of an anergic state in immunocompetent cells we examined the effect of an increase in intracellular calcium concentration on the subsequent responsiveness of cytolytic T cells to antigenic stimulation in vitro. Pretreatment of a murine cytolytic T cell clone with the calcium-ionophore A23187 resulted in the induction of an anergic state characterized by a decrease in cytolytic activity and granule exocytosis upon Ag-specific stimulation. Furthermore, IFN-gamma synthesis declined whereas de novo synthesis of a yet unidentified protein with a molecular mass of 33 kDa as well as proliferative response of cells in response to exogenous IL-2 were unaffected. This state of partial unresponsiveness 1) could be prevented by concomitant pretreatment of cells with cyclosporin A or protein synthesis inhibitors and 2) was reversible within 48 h. Biochemical analysis of TCR-induced intracellular activation revealed a block in signal transduction before the activation of protein kinase C because cellular unresponsiveness could be bypassed by the phorbol ester PMA plus the calcium-ionophore A23187. However, phosphatidylinositol turnover was markedly inhibited in unresponsive cells that also did not show a calcium influx on stimulation with concanavalin A. We conclude that a rise in intracellular calcium in cytolytic T cells might not only be necessary for cellular activation but may also trigger the induction of a partial unresponsiveness to antigenic stimulation due to an inhibition in the early phase of signal transduction.
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PMID:Functional and biochemical characterization of a calcium-ionophore-induced state of unresponsiveness in a cytolytic T cell clone. 131 47

The effect of IFN-gamma and TNF-alpha treatment of an ovarian carcinoma line on the sensitivity to lysis by specific CTL clones and non-specific Tumor Associated Lymphocytes (TAL), isolated from the ascites fluid, was analyzed. The in vitro established TAL line displayed a non-specific lytic activity against the autologous tumor as well as against several allogeneic tumor lines. Pretreatment with IFN-gamma alone, or in combination with TNF-alpha, rendered the carcinoma line less susceptible to lysis by the autologous TAL line. Conversely, susceptibility to lysis by tumor specific T cell clones, isolated from the TAL line, was increased as a result of cytokine pretreatment. Several TCR-alpha/beta+, CD8+ T-cell clones showing a more specific pattern of lysis against the autologous tumor were isolated. Lysis of the autologous tumor by these clones involved the TCR-alpha/beta via a MHC-class I restricted mechanism dependent on the adhesion molecules ICAM-1 and LFA-3, as inferred from antibody blocking studies. The enhanced sensitivity to specific CTL clones seen after cytokine treatment may be related to the enhanced expression of ICAM-1 molecules on the ovarian carcinoma. These results have implications for cytokine based immunotherapy, where IFN-gamma may enhance the effects of tumor associated specific CTL while decreasing that of non-specific effector cells.
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PMID:Diverse effect of cytokine treatment of tumor cells on specific versus non-specific cytotoxicity. 134 17

Activated CD4+ T cells can be classified into distinct subsets; the most divergent among them may be considered to be the IL-2 and IFN-gamma-producing Th1 clones and the IL-4 and IL-5-producing Th2 clones. Because Th1 and Th2 clones can usually be detected only after several months of culture, we used conditions that modulate the IL-2 and IL-4 production in short term culture. Here we show that freshly isolated and subsequently in vitro-activated CD4+ T cells that were cultured for 11 days with rIL-2 and restimulated showed a IFN-gamma+ IL-2+ IL-3+ IL-4- IL-5- pattern. Because these cells were not capable of providing B cell help for IgG1, IgG2a, or IgE in an APC- and TCR-dependent T-B cell assay, they expressed a phenotype typical for most Th1 clones. In contrast, activated T cells that were cultured for 11 days with IL-2 plus a mAb to CD3 and then restimulated produced a IFN-gamma- IL-2- IL-3+ IL-4+ IL-5+ pattern. These cells were capable of providing B cell help for IgG1, IgG2a, and IgE synthesis and thus presented a phenotype typical for Th2 clones. Similar results were observed when mitogenic mAb to Thy-1.2 or to framework determinants of the alpha beta TCR were used. The induction of Th1- and Th2-like cells did not depend on the relative expression of CD44 or CD45 by the T cells before activation in vitro. Because the incubation of activated T cells with anti-CD3/TCR mAb induced high unrestricted lymphokine production, the latter might be responsible for the Th2-like lymphokine pattern observed after restimulation. To address this point, TCR V beta 8+ and V beta 8- T cell blasts were co-cultured in the presence of mAb to V beta 8. After restimulation, V beta 8+ cells had a IL-4high IL-2low phenotype and V beta 8- cells had a IL-4low IL-2high phenotype. This demonstrates that TCR ligation but not lymphokines alone are capable of inducing Th2-like cells, and this points out a central role for the TCR in the generation of T cell subsets.
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PMID:Central role for TCR/CD3 ligation in the differentiation of CD4+ T cells toward A Th1 or Th2 functional phenotype. 134 89

Panels of nickel-specific T-lymphocyte clones (TLC) were prepared from nickel-allergic and non-allergic donors. TLC from both panels showed similar levels of expression of TCR alpha/beta, CD4, CD2, CD25, and CD29 and recognized nickel in association with class II HLA molecules with restriction determinants in HLA-DR, HLA-DP, and HLA-DQ. The lymphokine secretion was analyzed in TLC from both panels upon antigen-specific or non-specific stimulation and was compared with the secretion profiles of representants of pre-established human atopen-specific Th1 and Th2 cells. Nickel-specific TLC from both panels showed a lymphokine secretion pattern similar to the atopen-specific Th1 cells, although there was some variation from clone to clone. Most TLC secreted substantial amounts of IFN-gamma, IL-2, TNF-alpha, and GM-CSF, but little or no IL-4 and IL-5. The variation observed mainly concerned IL-2 secretion that could be low or absent in some of the TLC. The general secretion pattern did not change upon different modes of stimulation, including activation via CD3, CD2, or CD28. Because nickel-specific TLC from allergic and non-allergic individuals show a similar Th1 secretion pattern, the present results give no evidence that aberrant lymphokine secretion by CD4+T cells determines the contact allergic state, as was found for atopic allergy in a previous study.
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PMID:Th1 lymphokine production profiles of nickel-specific CD4+T-lymphocyte clones from nickel contact allergic and non-allergic individuals. 134 23

Cloned CD4 T cells of the Th2 type make IL-4 and related cytokines upon receptor cross-linking, whereas cloned CD4 T cells of the Th1 type make IL-2, IFN-gamma, and TNF-beta. These two types of CD4 T cell are also reported to use distinct mechanisms of signal transduction. It has been reported that Th1 cells flux Ca2+ upon receptor cross-linking, whereas Th2 cells do not. We have noted that when cloned Th2 cells are exposed to high levels (20 U/ml) of IL-2, they show an altered phenotype. Such cells are much more sensitive to activation by certain antireceptor antibodies, they flux calcium upon receptor ligation without additional cross-linking with anti-Ig antibodies, and they make much larger amounts of IL-4. In addition, the organization of their TCR is altered, with increased levels of the TCR-eta chain and an increase in the extent of association of CD4 with CD3 and CD45, changes similar to those found in Th1 cells. These results suggest that there is no fundamental difference in the signal transduction apparatus of Th1 and Th2 cells; rather, the IL-2 made by Th1 cells may create similar phenotypic changes in these cells and thus create the impression of altered signal transduction mechanisms. These results do show that exposure to high levels of IL-2 can profoundly affect signal transduction in T cells. Furthermore, we found that the Ca2+ signal caused by CD3 antibodies seemed to differ in character from that caused by TCR antibodies suggesting that the use of CD3 antibodies is not always a good model for activation through the TCR.
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PMID:High levels of IL-2 alter signal transduction in cloned IL-4-producing CD4 T cells. 135 32

We have analyzed the effects of NK cell stimulatory factor/IL-12, on proliferation of PBL and their subsets. IL-12 synergizes with lectins and phorbol diesters to induce proliferation of CD4+ and CD8+ peripheral blood T lymphocytes. In the case of phorbol-diester-induced proliferation, the effect of IL-12 is in part mediated by induced IL-2 production, as suggested by the observation that IL-12 enhances IL-2 production in these cultures and that anti-IL-2 antibodies inhibit proliferation. IL-12 synergizes also with anti-CD3 antibodies and with allogeneic stimulation in MLC in inducing T cell proliferation. IL-12 alone is mitogenic for preactivated T and NK lymphoblasts. This mitogenic effect is observed with similar doses of IL-12 on NK lymphoblasts as well as on CD4+ and CD8+ TCR-alpha beta+ and on TCR-gamma delta+ lymphoblasts. On TCR-alpha beta+ T lymphocytes the effect of IL-12 is always additive to that of IL-2 over a wide dose range. The same effect is observed on highly activated, actively proliferating NK cells. However, on NK and TCR-gamma delta+ lymphoblasts reverting to a resting state after stimulation and on a TCR-gamma delta+ acute leukemia-derived T cell line, IL-12 inhibits significantly the proliferation induced by moderate to high doses (10 to 100 U/ml) of IL-2. This inhibitory effect is, at least in part, indirect, and depends on IL-12-induced production of TNF. Neutralizing anti-TNF antibodies, but not anti-IFN-gamma and anti-transforming growth factor antibodies, restore by more than 70% the inhibition of proliferation induced by IL-12 in these cultures. However, TNF alone cannot mimic the inhibitory effect of IL-12 on the IL-2-induced proliferation of NK and TCR-gamma delta+ lymphoblasts, suggesting the involvement of additional mechanisms. The relevance of these findings for the biology of lymphocyte subsets mediating MHC nonrestricted cytotoxicity is discussed.
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PMID:Natural killer (NK) cell stimulatory factor or IL-12 has differential effects on the proliferation of TCR-alpha beta+, TCR-gamma delta+ T lymphocytes, and NK cells. 135 72

T-cells have been implicated in autoimmune renal injury. To examine the role of T-cells in lupus nephritis we propagated T-cell clones from the cortical interstitium of MRL/lpr mice. All isolated kidney-infiltrating (KI) T-cell clones [6] express surface markers identical to the T-cells regulated by the lpr gene (Thy 1.2+, TCR alpha/beta +, Lyt-2-, L3T4-, B220+). Although KI T-cell clones have the same surface markers as lymph node-infiltrating (LNI) T-cells, they differ functionally. KI T-cells, but not LNI T-cells, are autoreactive and kidney-specific, exclusively proliferating to renal tubular epithelial (TEC) and mesangial cells. In addition, unlike LNI T-cell supernatants (SN), KI T-cell clones SN induce class II and ICAM-1 on cultured TEC. When KI T-cell clones are injected under the renal capsule, class II is increased on TEC. All clones transcribe mRNA for cytokines capable of inducing class II and ICAM-1 (IL-4, TNF-alpha, IFN-gamma). Anti-IFN-gamma mAb prevents the induction of class II and ICAM-1 on cultured TEC. Since class II and ICAM-1 expression on TEC precedes renal injury, the ability to propagate autoreactive, kidney-specific T-cell clones that induce these molecules provides evidence for their role in initiating renal injury in MRL/lpr mice.
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PMID:Autoreactive kidney-infiltrating T-cell clones in murine lupus nephritis. 136 May 51

Cloned human CD4+ T cell lines specific for the house dust mite Dermatophagoides pteronyssinus were used to map minimal T cell activation-inducing epitopes on the Group I allergen in D. pteronyssinus extracts (Der p I) molecule. Most of these Der p I-specific T cell clones expressed different TCR V alpha and V beta gene products. Using recombinant deletion proteins, three T cell epitopes were identified on the Der p I molecule; p45-67 and p117-143 were recognized by HLA-DR7-restricted T cells, whereas p94-104 was recognized in the context of HLA-DR2, DRw11 (DR5), and -DR8 molecules. This degenerate class II MHC restriction appears to be due to shared Phe and Asp residues at positions 67 and 70, respectively, in the third variable domain of the HLA-DR beta chain. All three T cell epitopes induced Th2-like cytokine production profiles by the Der p I-specific T cell clones, which were characterized by the production of very high levels of IL-4 and IL-5, as compared with those secreted by tetanus toxin-specific T cell clones derived from the same patients, but no or low amounts of IL-2 and IFN-gamma. This Th2-like production profile was, however, not an intrinsic property of the Der p I-specific T cells, but was dependent upon their mode of activation. Stimulation with Con A also induced very low or no measurable levels of IL-2 and IFN-gamma, whereas activation with TPA and the calcium ionophore A23187 resulted in the production of high levels of IL-4, IL-5, IL-2, and IFN-gamma. These results indicate that Der p I-specific T cell clones are not defective in their capacity to produce high levels of Th1 cytokines.
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PMID:T cell activation-inducing epitopes of the house dust mite allergen Der p I. Proliferation and lymphokine production patterns by Der p I-specific CD4+ T cell clones. 137 May 14


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