UNIPROT:P14784 - FACTA Search

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Query: UNIPROT:P14784 (IL-2 receptor)
3,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In rheumatoid arthritis and other inflammatory diseases we and others have found that gamma delta T cells express activation antigens, suggesting that they are involved in the pathogenesis of these disorders. In this study we have stimulated peripheral blood mononuclear cells from normal donors with recombinant interleukin-2 (rIL-2) to see whether such a stimulus alone could activate gamma delta T cells. Short-term exposure (24-96 h) to rIL-2 selectively stimulated the gamma delta but not the alpha beta T cells to express activation antigens (CD69, CD25 and HLA-DR). Long-term culture (2 weeks) in rIL-2-containing medium caused a selective increase in the proportion of the gamma delta T cells and a corresponding reduction of the fraction of alpha beta T cells. Limiting dilution analysis revealed that approximately 1/60 of the gamma delta T cells responded to IL-2 in contrast to only 1/250 of the alpha beta T cells. Comparison of the expression of the IL-2 receptor (IL-2R) alpha and beta chains showed that there was a similar expression of the alpha chain on gamma delta and alpha beta T cells whereas the relative density of the beta chain was more than twice as high on gamma delta T cells. Both the IL-2-induced proliferation of gamma delta T cells and the expression of activation antigens on these cells could be inhibited by an anti-IL-2R beta monoclonal antibody (mAb) but not by an anti-IL-2R alpha mAb. Expression of CD69 on gamma delta T cells was dependent neither on the presence of B cells, monocytes, nor alpha beta T cells. Finally, we found that the IL-2-induced expression of CD69 was inhibited by activation of cAMP-dependent protein kinase and by inhibition of the Src-family of the tyrosine protein kinase, but not by inhibition of protein kinase C or by activation of the CD45 associated tyrosine phosphatase. The ability of gamma delta T cells to be activated by IL-2 is a feature which they have in common with natural killer cells. Moreover, it may be possible that the expression of activation antigens on gamma delta T cells in inflammatory diseases is an epiphenomenon secondary to IL-2 produced by activated alpha beta T cells.
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PMID:Selective activation of resting human gamma delta T lymphocytes by interleukin-2. 837 Mar 91

The association of rheumatoid arthritis (RA) with particular MHC class II genes suggests that autoantigen-specific T cell clones present in joints could be central to the pathogenesis of the disease. Previous investigations on the clonal diversity of T cells infiltrating the rheumatoid synovial membrane have yielded conflicting results. With the use of Southern blot analysis, we investigated the clonality of rheumatoid T cell lines expanded from peripheral blood, synovial fluid and synovial tissue. From peripheral blood lymphocyte (PBL) of RA patients and healthy normal controls, we also checked the consequences of two different culture conditions on the clonality of these cell lines. From control PBL, we found that in vitro non-specific expansion of non-clonal T cell populations does not create artefactual clonal selection. However, growing T cells in vitro with IL-2 seems to be able to lead to preferential expansion of cells bearing IL-2 receptor (IL-2R). We identified such in vivo activated IL-2-sensitive T cell clones frequently in RA synovial tissue (8/13) and more rarely in synovial fluid and peripheral blood (3/12). One patient presents the same T cell receptor gene rearrangements in synovial membrane of two affected joints. In RA synovial tissue, the frequency of these IL-2-responsive T cells is most prevalent among actively inflamed membranes removed early in the disease process. The role and the relevance to the disease of these IL-2-responsive T cells remain to be elucidated.
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PMID:Clonality of T lymphocytes expanded with IL-2 from rheumatoid arthritis peripheral blood, synovial fluid and synovial membrane. 838 Mar 69

With the exception of certain hematologic malignancies, the high affinity interleukin-2 (IL-2) receptor is only transiently expressed during the brief antigen-triggered proliferative burst of lymphocytes. Hence, we wondered whether administration of anti-IL-2 receptor (IL-2R) monoclonal antibody (mAb) or chimeric IL-2 toxins would provide a utilitarian way to achieve immunosuppression aimed directly at activated lymphocytes, or whether this approach could be used to treat IL-2R+ leukemia/lymphoma. Studies in preclinical autoimmune and transplant models indicate that this approach can be effective. The results of open, uncontrolled studies provide preliminary evidence that a chimeric IL-2 toxin is well tolerated at doses that may induce improvement in patients with IL-2R+ leukemia/lymphoma, as well as in patients with refractory rheumatoid arthritis or new-onset diabetes mellitus.
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PMID:Interleukin-2 receptor-directed therapies: antibody-or cytokine-based targeting molecules. 847 55

Superantigen-mediated T cell activation requires the participation of antigen-presenting cells (APC). Once superantigen has bound class II MHC molecules on the surface of APC, it then can interact with the T cell receptor to induce T cell activation. Superantigen-mediated T lymphocyte activation, along with its consequent cytokine production is thought to be the basis for the pathophysiology of conditions such as toxic shock syndrome, Kawasaki's disease and possibly rheumatoid arthritis. We examined the role of CD56+ NK lymphocytes in the interaction between superantigens and T lymphocytes. First, we found that a subpopulation of CD56+ cells freshly isolated from human peripheral blood expressed class II MHC molecules. The amount of HLA-DR expression varied between individuals, ranging from 9.3% to 37.7%. CD56+ (NK) cells were purified from the peripheral blood by cell sorting and were tested for their ability to support SEB-mediated T cell activation as assessed by surface expression of IL-2 receptor alpha-chain (CD25) on CD3+ lymphocytes. We observed that when enriched T cells were incubated with SEB in the presence of NK cells, there was a significant up-regulation of CD25 expression of the T cells. When HLA-DR+ cells were removed from sorted CD56+ populations, the remaining HLA-DR- NK cells were unable to support SEB-mediated T cell activation. Also, SEB up-regulated the expression of HLA-DR on CD56+ cells in peripheral blood mononuclear cell (PBMC) populations after 24 h of incubation, implying that the ability of NK cells to function as superantigen-presenting cells is up-regulated by superantigens themselves. Together, these data demonstrate for the first time that human CD56+ HLA-DR+ NK cells can function as superantigen-presenting cells, and imply that NK cells may be involved in the activation of non-specific T cell reactivity during early host defences against superantigen-elaborating microorganisms in vivo. Furthermore, the physical linkage of NK cells and T cells by the interaction of superantigen with HLA class II molecules and T cell receptors, respectively, may lead to NK cell activation and augmented lytic potential, helping to clear the body of superantigen-elaborating microorganisms.
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PMID:Human natural killer (NK) cells present staphylococcal enterotoxin B (SEB) to T lymphocytes. 862 34

The aim of this study was to quantify and characterize the CD4+ and CD8+, CD45RA+, CD45RO- T-lymphocytes that paradoxically expressed the CD29 bright+ phenotype in health and in rheumatoid arthritis. We further evaluated their clinical implications. Blood samples were obtained from 100 patients with rheumatoid arthritis and 40 age- and sex-matched controls. Cell surface antigens and interleukin-2 (IL-2) binding were detected on CD4+ and CD8+ peripheral blood T-lymphocytes (T-PBL) by three-colour flow cytometry. One-third of the patients were clinically evaluated at the time of blood sampling. In healthy donors, we found 16 +/- 14% of CD29 bright+ cells among CD4+, CD45RA+, RO- T-PBL. These "false naive" CD4+ T-PBL were Leu-8+, and a majority expressed the CD25/p55 receptor (IL-2R alpha chain), while a minority showed the CD11a bright+, CD69+ and/or CD122/p75+ (IL-2R beta chain) phenotype, and few cells were CD31 bright+ and HLA-DR+. In rheumatoid arthritis, their proportion among CD4+, CD45RA+, RO- cells increased to 25 +/- 15% (P < 0.001, compared with controls). In patients, the reductions in CD31 and CD38 expression (P < 0.05 for both), as well as the enhanced CD25 expression (P < 0.001) on CD4+, CD45RA+, RO- T-PBL reflected a more differentiated phenotype. The occurrences of CD25 and CD122 were increased on false naive CD4+ T-PBL (0.01 < P < 0.001); however, the binding of IL-2 remained very low (in contrast to the binding of IL-2 on CD45RO+ T-PBL). Furthermore, a major subset of CD8+, CD45RA+, RO- T-PBL (45 +/- 17% in controls) expressed the CD29 bright+ phenotype. These "false naive" CD8+ T-PBL included a great many of CD11b+, CD28- cells, while a minority showed the HLA-DR+, CD69+ and/or CD122+ phenotypes. Patients with low levels of IgM rheumatoid factors (IgM-RF; but with active disease) had an elevated proportion of CD45RA+, RO- cells among the CD8+ T-PBL, in part due to an increased proportion of false naive cells (P < 0.05). In patients, the false naive CD8+ T-PBL showed down-regulated CD11b and an increased expression of IL-2 receptor chains (CD25 and CD122; 0.05 < P < 0.01), but without a significant increase in IL-2 binding. More CD69 on false naive CD8+ T-PBL was found in patients with high levels of IgM-RF (P < 0.005 compared to patients with low IgM-RF). Finally, both false naive CD4+ and CD8+ T-PBL correlated with the clinical process and outcome variables (0.05 < P < 0.01). The levels of activated false naive (CD4+ T-PBL (CD25+ and/or CD122+) or CD8+ T-PBL (CD69+ and/or CD122+) were associated with clinical parameters of disease activity (0.05 < P < 0.01). Thus, in rheumatoid arthritis, false naive T-PBL showed important qualitative differences. The levels of activated false naive T-PBL could be particularly interesting for monitoring disease evolution.
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PMID:Flow cytometric characterisation of the "false naive" (CD45RA+, CD45RO-, CD29 bright+) peripheral blood T-lymphocytes in health and in rheumatoid arthritis. 885 29

Interleukin-15 (IL-15) is a recently characterized cytokine that shares many biological activities with IL-2 and interacts with the beta and gamma components of the IL-2 receptor. Unlike IL-2, which is secreted only by T cells, IL-15 is expressed preferentially by nonlymphoid tissues, epithelial, and fibroblast cell lines and by activated monocytes/macrophages. High concentrations of IL-15 have been shown in inflamed joints of rheumatoid arthritis patients, suggesting a role for IL-15 in inflammatory diseases where there is recruitment of leukocytes. Although monocytes have been shown to bind IL-15, its effects on these cells are not defined. In this report we show that supernatants of monocytes treated with IL-15-contained chemotactic activity for neutrophils and monocytes which was neutralized by anti-IL-8 or by anti-monocyte chemotactic protein 1 (MCP-1) antibodies, respectively. Secretion of IL-8 and MCP-1 proteins is detectable by enzyme-linked immunosorbent assay as early as 6 hours after stimulation with IL-15. Production of the two chemokines is correlated with induction by IL-15 of mRNA expression in monocytes. In addition, IL-8 and MCP-1 induction by IL-15 is differently regulated by interferon-gamma (IFN-gamma) and IL-4. IFN-gamma inhibited IL-15-induced IL-8 secretion, but synergized with IL-15 in MCP-1 induction; whereas IL-4 inhibited both IL-8 and MCP-1 induction by IL-15. These results show that IL-15 can stimulate monocytes to produce chemokines that cause inflammatory cell accumulation. Thus, IL-15 locally produced at sites of inflammation may play a pivotal role in the regulation of the leukocyte infiltrate.
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PMID:Interleukin-15 (IL-15) induces IL-8 and monocyte chemotactic protein 1 production in human monocytes. 932 48

In rheumatoid arthritis (RA), T cells in the inflamed joint are considered to play a crucial role in the pathogenesis. However, despite the fact that synovial T cells have an activated memory phenotype, they are functionally suppressed upon combined CD3 and CD28 stimulation. Here, we analyzed the contribution of both CD3 and CD28 to the hyporesponsiveness of synovial T cells in RA. In contrast to the low CD3 responsiveness of synovial fluid (SF) T cells compared to peripheral blood (PB) T cells, the CD28 co-stimulatory response was observed to be unaffected. Hyporesponsiveness of SF T cells has previously been associated with decreased levels of intracellular glutathione (GSH), an antioxidant and regulator of the intracellular redox state. Treatment of SF T cells with N-acetylcysteine, an antioxidant and replenisher of GSH, selectively improved CD3-induced responses, while leaving CD28 responsiveness unaffected. These data show that the CD3 pathway is highly sensitive to intracellular GSH alterations, whereas CD28 responsiveness is relatively refractory. Furthermore, in support for a functional role of CD28 co-stimulation, it was demonstrated that CD28 ligation acted in synergy with the IL-2 receptor gamma chain signaling cytokine IL-15 in the enhancement of the ex vivo survival of SF T cells. These data indicate that CD28 co-stimulatory capacity of SF T cells, in contrast to CD3 stimulation, remains intact despite an altered intracellular redox state. Thereby, CD28 stimulation may contribute to the persistence of T cells at the site of inflammation, which might be of relevance in the pathogenesis of RA.
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PMID:CD28 co-stimulation is intact and contributes to prolonged ex vivo survival of hyporesponsive synovial fluid T cells in rheumatoid arthritis. 960 60

This review focuses on the biological effects of the newly discovered cytokine, interleukin 15 (IL-15), in chronic inflammatory disorders. IL-15 shares biological activities with IL-2, and like IL-2 it is a member of the four-helix bundle cytokine family. IL-15 interacts with a heterotrimeric receptor that consists of the beta and gamma subunits of the IL-2 receptor (IL-2R) as well as a specific, high-affinity IL-15-binding subunit, IL-1SRalpha. IL-15 is produced by macrophages and various other cells in response to environmental stimuli and infectious agents, and it is important for the growth and differentiation of T and B lymphocytes, natural killer cells, macrophages, and monocytes as well as it activates a number of important intracellular signaling molecules, including the Janus kinases and members of the transcription factor family of signal transducers and activators of transcription. These facts suggest that IL- 15 may play a pivotal role both in protective immune responses and in the pathogenesis of various chronic immuno-inflammatory disorders. The important new insight into the role of IL-15 in diseases such as rheumatoid arthritis, sarcoidosis, chronic hepatitis C, and ulcerative colitis are reviewed in this paper.
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PMID:Interleukin-15 and its role in chronic inflammatory diseases. 971 92

Interleukin-15 (IL-15) is a 14- to 15-kDa member of the 4 alpha-helix bundle family of cytokines. IL-15 expression is controlled at the levels of transcription, translation, and intracellular trafficking. In particular, IL-15 protein is posttranscriptionally regulated by multiple controlling elements that impede translation, including 12 upstream AUGs of the 5' UTR, 2 unusual signal peptides, and the C-terminus of the mature protein. IL-15 uses two distinct receptor and signaling pathways. In T and NK cells the IL-15 receptor includes IL-2/15R beta and gamma c subunits, which are shared with IL-2, and an IL-15-specific receptor subunit, IL-15R alpha. Mast cells respond to IL-15 with a receptor system that does not share elements with the IL-2 receptor but uses a novel 60- to 65-kDa IL-15RX subunit. In mast cells IL-15 signaling involves Jak2/STAT5 activation rather than the Jak1/Jak3 and STAT5/STAT3 system used in activated T cells. In addition to its other functional activities in immune and nonimmune cells, IL-15 plays a pivotal role in the development, survival, and function of NK cells. Abnormalities of IL-15 expression have been described in patients with rheumatoid arthritis or inflammatory bowel disease and in diseases associated with the retroviruses HIV and HTLV-I. New approaches directed toward IL-15, its receptor, or its signaling pathway may be of value in the therapy of these disorders.
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PMID:The multifaceted regulation of interleukin-15 expression and the role of this cytokine in NK cell differentiation and host response to intracellular pathogens. 1035 52

Rats injected in the hind paw with a mixture of Mycobacterium butirricum emulsified in mineral oil (FA) developed a severe polyarthritis that shared some immunological features with human rheumatoid arthritis. After this local administration, rats developed a secondary lesion (edema) in the contralateral paw, which is a hallmark of immune system activation. In vivo intravenous treatment with a monoclonal anti-very late antigen (VLA)-1 antibody (HA31/8) significantly reduced the edema formation in the contralateral paw. T cells isolated from contralateral paw draining lymph nodes of FA rats treated with HA31/8 showed a reduced cell proliferation in vitro, after stimulation with concanavalin A. Furthermore FACS analysis showed that the reduction in proliferation was concomitant to a reduction in the number of T cells positive to surface IL-2 receptor expression. Our data indicate that after in vivo treatment with a monoclonal anti-very late antigen-1 antibody, there is a beneficial effect on the development of the secondary lesion, which correlates to the reduced ability of T cells to proliferate in vitro as well as to a reduced surface expression of IL-2 receptor. The association of this antibody to other drugs interfering at other levels in rheumatoid arthritis may open a new therapeutic window.
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PMID:Anti-very late antigen-1 monoclonal antibody modulates the development of secondary lesion and T-cell response in experimental arthritis. 1065 5

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