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

Two T-lymphocyte subsets develop in the thymus which differ in the expression of glycoproteins on their cell surface. About 60% of the circulating T cells express the glycoprotein T4, while about 30% have the glycoprotein T8. T4 and T8 cells can be determined in the peripheral blood or various organs with monoclonal antibodies. T4 and T8 cells differ in their antigen recognition, have different functions, and can cause various pathohistological changes. T4 cells recognize the antigen in association with the HLA-D/DR/DP determinants. Upon antigenic stimulation they liberate various factors and initiate and amplify an immune response (T4 = helper/inducer T-cells). They can also be cytotoxic and are mediating effector functions via macrophage activation. T8 cells recognize the antigen in association with HLA-A/B/C determinants. They exert their cytotoxic or suppressive effector functions mainly in viral infections. The T4 or T8 cell-mediated pathohistological changes are discussed in the light of the well studied T-cell infiltrations in lepra lepromatosa or lepra tuberculosa. The T4/T8 cell dyscrasia in the peripheral blood, described in a variety of infectious, autoimmune or immunodeficiency diseases, may be due to enhanced proliferation, selective sequestration, reduced production or the elimination of a subset. T-cell subset analysis in joints, bronchial lavages and tissues has clarified the pathomechanism in a variety of autoimmune diseases, although the etiology remains obscure. For example, in rheumatoid arthritis, multiple sclerosis, and sarcoidosis, a T4 cell-mediated reaction with macrophage activation can be found. T4/T8 cell analysis may also be of value in dissecting heterogenous diseases, e.g. systemic lupus erythematosus. Of value is also the additional demonstration of membrane components reflecting T-cell activation (IL-2 receptor or DR-antigen expression) which serves to identify the activated T-cell subset in peripheral blood. Finally, T4/T8 cell analysis can be helpful in deciding treatment, as the T-cell subsets have a different sensitivity to immunosuppressive drugs.
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PMID:[Analysis of T-cell subpopulations. Pathophysiological concept and significance for clinical medicine]. 315 84

This review covers significant developments in the understanding of the biochemistry and clinical pharmacology of Interleukin-2 (IL-2) that were achieved from 1984 through September 1986. These include developments in the molecular biology of IL-2 and its receptors. Human IL-2 was cloned and sequenced by Taniguchi et al. in 1983. The gene for human IL-2 is located on the long arm of chromosome 4. The secondary structure of the gene is predominantly alpha helix. The mature gene product is a 133 amino acid glycoprotein with a molecular weight of 15,420 Daltons. The IL-2 receptor was revealed to be a glycoprotein of 272 amino acids. The mature receptor has a molecular weight of 55,000 Daltons. A more precise understanding of the mechanism of action IL-2, in particular its role in the induction of the IL-2 receptor, and aspects of the control of IL-2 production was also achieved. Metabolic and morphologic studies have revealed that activation of the T-cell antigen receptor renders the cells responsive to IL-2, but does not move them through the cell cycle. Rather, it appears that IL-2 stimulates G1 progression to S phase ie. blastic transformation. During this progression the cellular proto-oncogene c-myb is induced transiently to 6 to 7 times basal levels. The role of IL-2 as a growth factor for several subsets of T cells has been confirmed, and a new role as a growth factor for B cells was defined. Most importantly, IL-2 was shown to be directly mitogenic for and to expand subpopulations of peripheral blood cells, termed lymphokine-activated killer (LAK) cells and tumor-infiltrating lymphocytes (TIL). A number of pathologies of IL-2 production or activity have been defined, including Hodgkin's disease, graft versus host disease, systemic lupus erythematosus, lepromatous leprosy, acquired immune deficiency syndrome, and adult T cell leukemia. Murine and human in vivo studies reviewed here have revealed significant parameters of the therapeutic potential as well as the toxicity of this growth factor. Finally, the modulation of IL-2 receptors on human PBL's by thymosin fraction 5 and thymosin alpha 1 suggests that it might be possible to up-regulate IL-2 receptor expression in certain disease states and thus increase the efficacy of IL-2.
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PMID:Recent advances in the understanding of the biochemistry and clinical pharmacology of interleukin-2. 354 63

Anti-murine interleukin 2 (IL-2) receptor monoclonal antibodies (mAb) were made from rats immunized with murine cytotoxic lymphocytes. One mAb, designated M7/20, strongly inhibited the proliferation of both IL-2 dependent CTLL-2 cells and concanavalin A (Con A)-induced T-cell blasts. Inhibition was linearly dependent on the concentrations of both M7/20 and IL-2. Utilizing FACS analysis, M7/20 was shown to bind selectively to mitogen-activated T lymphocytes and, to a lesser degree, to activated B lymphocytes. 125I-Labeled M7/20 binding assays indicated that 48-hr Con A-induced T-cell blasts possessed 89,000 binding sites/cell with a Kd of 1.2 X 10(-9) M. Competitive binding analyses indicated that M7/20 and IL-2 occupy the same or overlapping cell surface sites. Preliminary biochemical characterization of M7/20 immunoprecipitates of detergent extracts from both surface-iodinated and internally D-[3H]glucosamine-labeled T lymphoblasts indicated that the murine IL-2 receptor is an N-glycosylated 58,000-Da glycoprotein. Together these results suggest that mAb M7/20 binds at or near the IL-2-binding epitope on the murine IL-2 receptor and, thus, upon manipulation may act as an IL-2 agonist.
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PMID:Characterization of a monoclonal rat anti-mouse interleukin 2 (IL-2) receptor antibody and its use in the biochemical characterization of the murine IL-2 receptor. 392 55

T lymphocytes, essential for the generation of a normal immune response, require the presence of the lymphokine interleukin-2 (IL-2) in order to proliferate. Cells that respond to IL-2 possess a surface receptor glycoprotein specific for this lymphokine. We have recently purified and chemically characterized the IL-2 receptor from both phytohaemagglutinin-activated human T cells and the human T-cell lymphoma HUT-102 (ref. 5). From the NH2-terminal protein sequence obtained in that study, we have now used synthetic oligonucleotides to probe a complementary DNA library, prepared from HUT-102 messenger RNA, for the presence of cDNA clones that might code for the IL-2 receptor. Two cDNA clones were isolated which had closely related DNA sequences. Interestingly, only one coded for an active receptor when transfected into COS-7 cells. This clone contained a 216-base pair (bp) insert that was not present in the other clone. The insert was flanked by an 8-bp direct repeat reminiscent of a transposable element, and appeared to code for a region of marked structural homology to the NH2-terminal region of the receptor molecule.
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PMID:Cloning, sequence and expression of human interleukin-2 receptor. 609 20

Recent studies using cloned antigen-specific T lymphocytes and monoclonal antibodies directed at their various surface glycoprotein components have led to identification of the human T cell antigen receptor as a surface complex comprised of a clonotypic 90KD Ti heterodimer and the monomorphic 20/25KD T3 molecules. Approximately 30,000-40,000 Ti and T3 molecules exist on the surface of human T lymphocytes. These glycoproteins are acquired and fully expressed during late thymic ontogeny, thus providing the structural basis for immunologic competence. The alpha and beta subunits of Ti bear no precursor-product relationship to one another and are encoded by separate genes. The presence of unique peptides following proteolysis of different Ti molecules isolated by noncrossreactive anticlonotypic monoclonal antibodies supports the notion that variable regions exist within both the alpha and beta subunits. Moreover, N-terminal amino acid sequencing of the Ti beta subunit shows that it bears homology to the first V-region framework of immunoglobulin light chains and represents the product of a gene that rearranges specifically in T lymphocytes. Soluble or Sepharose-bound anti-Ti monoclonal antibodies, like physiologic ligand (antigen/MHC), enhanced proliferative responses to purified IL-2 by inducing a 6-fold increase in surface IL-2 receptor expression. In contrast, only Sepharose-bound anti-Ti or physiologic ligand triggered endogenous clonal IL-2 production and resulted in subsequent proliferation. The latter was blocked by antibodies directed at either the IL-2 receptor or IL-2 itself. These results suggest that induction of IL-2 receptor expression but not IL-2 release occurs in the absence of T3-Ti receptor crosslinking. Perhaps more importantly, the findings demonstrate that antigen-induced proliferation is mediated through an autocrine pathway involving endogenous IL-2 production, release, and subsequent binding to IL-2 receptors.
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PMID:Clonotypic surface structure on human T lymphocytes: functional and biochemical analysis of the antigen receptor complex. 633 44

A T cell growth factor-dependent alloreactive human T cell line has been used to generate a monoclonal antibody B1.49.9 that reacts with an antigen present on most if not all mitogen or alloantigen activated T cells but not on resting T cells. The T lymphoblastoid cell line HUT-102 is also strongly reactive with B1.49.9 but all other T and non-T leukemia-lymphoma cell lines tested were negative. The B1.49.9 antigen is a glycoprotein of 55,000 Mr on mitogen or alloantigen activated T cells and 50,000 Mr on the cell line HUT-102. Pulse labeling experiments showed that a 40,000 Mr precursor (at approximately 0.7 h) which does not bind to ricin lectin precedes the appearance of the ricin-binding 55,000 Mr form. Comparisons of the monoclonal antibody anti-Tac, which recognizes the IL-2 receptor, to B1.49.9 suggest that B1.49.9 also recognizes a structure similar or identical to the IL-2 receptor.
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PMID:A 55,000 Mr surface antigen on activated human T lymphocytes defined by a monoclonal antibody. 641 69

Human interleukin-2 (IL-2) is a glycoprotein of relative molecular mass (Mr) 15,000, which is released by T lymphocytes on stimulation with antigen or mitogen and functions as a T-cell growth factor (TCGF) by inducing proliferation of activated T cells. It is generally accepted that resting or activated B cells do not respond directly to IL-2 but require for their proliferation other T-cell-derived lymphokines usually referred to as B-cell growth factors (BCGFs). Recently, however, a monoclonal antibody reacting with the IL-2 receptor molecules expressed by activated T cells (anti-Tac) was shown to react also with certain B tumour cells; in addition, murine B cells proliferate in response to pure human IL-2. We now show that recombinant IL-2, derived from Escherichia coli expressing the human gene, is able to promote strong proliferation of human B cells activated with protein-A-rich Staphylococcus aureus Cowans strain I. Moreover, we demonstrate that the anti-Tac antibody also reacts with S. aureus-activated normal B cells and inhibits sharply the proliferative response of such cells to IL-2. Finally, immunoprecipitation experiments reveal that anti-Tac defines similar molecules on activated T and B cells.
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PMID:Human interleukin-2 promotes proliferation of activated B cells via surface receptors similar to those of activated T cells. 643 35

The gene regulatory functions of the human IL-2 receptor (IL-2R) were reconstituted in transiently transfected hepatoma cells. The combination of IL-2R beta and -gamma mediated a strong stimulation via the cytokine response element of the alpha 1-acid glycoprotein gene and the hematopoietin receptor response element, but none via the IL-6 response element or the sis-inducible element. IL-2R alpha enhanced 10-fold the sensitivity of the IL-2R beta.gamma complex to respond to IL-2 or IL-15, but did not modify the specificity or the magnitude of maximal gene regulation. A homodimerizing chimeric receptor G-CSFR-IL-2R beta could mimic the IL-2R action. The IL-2R-mediated gene regulation was similar to that seen with receptors for IL-4 and IL-7, but differed from that for IL-6 type cytokines, thrombopoietin, erythropoietin, and growth hormone. The activation of STAT proteins by the IL-2R was assessed in transfected L-cells and COS-1 cells. Although IL-2R subunits were highly expressed in these cells, no STAT protein activation was detectable. Transient overexpression of JAK3 was unable to change the signaling specificity of the hematopoietin receptors in rat hepatoma, L-, and COS cells, but established a prominent activation of the IL-6 response elements by the IL-2R and IL-4R in HepG2 cells. The data support the model that the IL-2R and related hematopoietin receptors produce at least two separate signals which control gene expression.
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PMID:The action of interleukin-2 receptor subunits defines a new type of signaling mechanism for hematopoietin receptors in hepatic cells and fibroblasts. 771 38

Intracellular parasites show host cell specificity, and precise information on the range of host cells is a prerequisite for the identification of host molecules that account for the specificity and are involved in entry processes. The sporozoite stage of the tick-borne protozoan parasite Theileria parva binds to and enters bovine lymphocytes, but precise information on the susceptibility of other cell types present at the tick attachment site is unavailable. We quantitatively examined the susceptibility of cell types known to be present at the tick attachment site by a previously established in vitro assay. Apart from lymphocytes, sporozoites also bind to and enter macrophages and afferent lymph veiled cells; they do not bind to or enter fibroblasts, granulocytes, or erythrocytes. Sporozoites are not phagocytosed by the macrophages or veiled cells but enter them as they do lymphocytes. Since the tick attachment site is a region of cellular inflammation, we also examined the effects of agents known to be present in this area on lymphocyte susceptibility. Short-term preincubation of lymphocytes with tick salivary gland extract, with compounds that induce lymphocyte proliferation, or with interleukin-2 (IL-2), a cytokine produced by activated lymphocytes, increased host cell susceptibility by between 30 and 60%. The IL-2-induced increase in host cell susceptibility could be prevented by treating the lymphocytes with the monoclonal antibody IL-A 111, which reacts with the bovine IL-2 receptor alpha chain and inhibits IL-2-driven cell proliferation. The changes induced by tick salivary gland extract and IL-2 occurred in less than 90 min. Similarly, peripheral blood mononuclear cells from an animal previously immunized with a nonrelated antigen (trypanosome variant surface glycoprotein) and stimulated in vitro with the same antigen showed increases in host cell susceptibility of between 70 and 125%. In contrast, treatment of lymphocytes with gamma interferon did not induce any increase in host cell susceptibility.
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PMID:Tick salivary gland extract and interleukin-2 stimulation enhance susceptibility of lymphocytes to infection by Theileria parva sporozoites. 845 54

Interleukin-13 (IL-13) is a cytokine secreted by activated T lymphocytes that shares many, but not all, biological activities with IL-4. These overlapping activities are probably due to the existence of common receptor components. Two proteins have been described as constituents of the IL-4 receptor, a approximately 140-kDa glycoprotein (IL-4R) and the gamma chain (gammac) of the IL-2 receptor, but neither of these proteins binds IL-13. We have cloned a cDNA encoding an IL-13 binding protein (IL-13R) from the Caki-1 human renal carcinoma cell line. The cloned cDNA encodes a 380-amino acid protein with two consensus patterns characteristic of the hematopoietic cytokine receptor family and a short cytoplasmic tail. The IL-13R shows homology with the IL-5 receptor, and to a lesser extent, with the prolactin receptor. COS-7 cells transfected with the IL-13R cDNA bind IL-13 with high affinity but do not bind IL-4. COS-7 cells co-transfected with the cloned IL-13R cDNA and IL-4R cDNA resulted in the reconstitution of a small number of receptors that recognized both IL-4 and IL-13. Reverse transcription-polymerase chain reaction analysis detected the receptor transcript only in cell lines known to bind IL-13.
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PMID:Cloning and characterization of a specific interleukin (IL)-13 binding protein structurally related to the IL-5 receptor alpha chain. 866 18


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