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

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

Human lymphocytes stimulated with phytohaemagglutinin (PHA) were fused with an HGPRT- murine lymphoma, BW5147, and a hybridoma BwFc93-1 was isolated and cloned in agarose. This human X mouse hybrid and nine clones derived from it were characterized by chromosome analysis, phenotypic and functional assays. Karyotyping and isoenzyme studies showed the presence of five human chromosomes in BwFc93-1 with preferential retention of three chromosomes--6, X and 15--in the clones. Membrane immunofluorescence analysis revealed that all the clones expressed human and mouse class 1 MHC antigens and the mouse T cell antigens Thy-1 and T200, but were devoid of human OKT3, OKT8 and mouse Lyt-2. Human OKT4 and OKM1 phenotypes were transiently expressed by one clone and mouse Lyt 1 by two other clones. Several T4-, Lyt-1- clones produced and bound human interleukin-2 (IL-2) indicating a lack of correlation between human T cell phenotype and function in those hybrids. There was also evidence of dichotomy in the secretion of IL-2 and expression of the IL-2 receptor since clones were identified which either bound or secreted IL-2. One clone expressing IL-2 receptors could be induced to produce human IL-2 by simultaneously stimulating with PHA and phorbol myristate acetate (PMA).
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PMID:Characterization of a human X mouse T cell hybridoma and identification of a clone secreting and binding interleukin-2. 660 21

Interleukin 15 (IL-15) is a novel cytokine that shares no homology with IL-2, but it requires the use of beta and gamma chains of the IL-2 receptor complex for binding and signaling. In vitro studies have shown induction of CTL and lymphokine-activated killer (LAK) cell activity in peripheral blood mononuclear cells (PBMCs) from normal donors by IL-15 against known tumor targets. The present study attempts to define the role of IL-15 in generating LAK activity from melanoma patient lymphocytes. PBMCs of patients newly diagnosed with metastatic melanoma were incubated with different doses of recombinant human IL-15 and tested against autologous tumor cells, LAK sensitive cell lines (i.e., FMEX and Daudi), as well as the natural killer-sensitive cell line K562, in a 15-h 51Cr release assay. The effect of IL-15 was found to be both time and dose dependent, with peak activity detected after 2 or 3 days of culture with 100 ng/ml of this cytokine. LAK and not CTL activity in patient PBMCs was detected by the inability of mAbs against CD4, CD8, and MHC class I to effectively block lysis of autologous tumor and FMEX melanoma cells. In addition, interaction via the CD18 adhesion molecule was shown to be critical in IL-15-induced LAK-mediated lysis of autologous tumor cells. Finally, incubation of patient PBMCs with IL-15 for 6 h resulted in the up-regulation of perforin mRNA transcription. These findings suggest that LAK activity can be generated from melanoma patient PBMCs in the presence of IL-15 to lyse autologous tumor cells in a non-MHC-restricted manner. This new cytokine may play an important role in antitumor immunity with a possible use for cancer immunotherapy.
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PMID:Interleukin 15 induction of lymphokine-activated killer cell function against autologous tumor cells in melanoma patient lymphocytes by a CD18-dependent, perforin-related mechanism. 758 40

This study evaluates the morphological and phenotypic changes that occur in squamous cell carcinoma of the head and neck when local infusions of interleukin-2 (IL-2) are given. Twelve patients were treated with a range of doses of IL-2 (3 x 10(3) to 3 x 10(6) international units/day) by continuous intra-arterial infusion for 10 days. Biopsies of the tumour were taken pre- and 48 h post-therapy, snap-frozen, cut, and examined histologically and immunocytochemically. Local infusions of IL-2 increase the numbers of antigen-presenting Langerhans cells (CD1a-positive) and infiltrating lymphocytes, predominantly of the CD3 and CD4 (T-helper) phenotypes. Locally infused IL-2 results in the expression of MHC (major histocompatibility complex) class II antigens on the surface of the tumour cells, capillary and post-capillary endothelial cells, and peri-tumoural macrophages. Intratumoural NK (natural killer) cells and CD8-positive (T-cytotoxic) infiltrating lymphocytes were not increased by this therapy and CD25 (IL-2 receptor) was only increased in those patients treated at the lower dose levels. The system of intra-arterial cytokine infusion into head and neck tumours developed in this study is a useful model to examine the biological effects of cytokines, since in vivo they are mainly produced and act locally. Furthermore, the infused tumours are easily accessible to biopsy. The results from studies such as this may influence the design of tumour-targeted cytokine gene therapy programmes.
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PMID:The phenotypic changes in tumour infiltrating lymphocytes and tumour cells following intra-arterial infusion of interleukin-2 in patients with squamous cell carcinoma. 763 27

The bacterial superantigen, staphylococcal enterotoxin A (SEA) activates T cells with high frequency and directs them to lyse MHC-class-II-expressing cells in superantigen-dependent cell-mediated cytotoxicity (SDCC). Treatment of mice with SEA induced strong CD8+ T-cell(CTL)-mediated SDCC, as well as abundant cytokine production from CD4+ and CD8+ T cells. However, both cytotoxicity and cytokine release were transient. In contrast, combined treatment with SEA and recombinant interleukin-2 (rIL-2) increased peak levels and maintained CTL activity. These effects were concomitant with an increased number of SEA-reactive V beta 11+ T cells. Both the CD4+ and CD8+ populations contained higher frequencies of cells expressing IL-2 receptor (IL-2R) alpha beta, which suggests that continuous IL-2R signaling preserves its high expression and subsequently prevents loss of growth factor signals necessary for expansion of T cells. Although IL-2R expression was increased among both CD4+ and CD8+ cells, only the cytotoxic function of CTL, but not cytokine production from either CD4 or CD8, was augmented. These findings demonstrate that treatment with rIL-2 potentiates superantigen-induced cytotoxicity and maintains high CTL activity. rIL-2 might therefore be useful in improving superantigen-based tumor therapy.
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PMID:Enhanced and prolonged efficacy of superantigen-induced cytotoxic T lymphocyte activity by interleukin-2 in vivo. 765 74

We report the cloning, expression and characterization of biologically active feline tumour necrosis factor-alpha (fTNF-alpha). Messenger RNA was extracted from feline peritoneal macrophage cultures and used to synthesize cDNA for polymerase chain reaction (PCR) amplification. The PCR products were cloned into the plasmid vector pCRII and sequenced, showing 99.3% homology with a published fTNF-alpha gene sequence. Subcloning into the vector pGEX-2T and subsequent expression resulted in a 43 kDa fusion protein of fTNF-alpha and glutathione S-transferase (GST). Thrombin cleavage of the fusion protein yielded a 17 kDa protein. This protein cross-reacted with a monoclonal anti-human TNF-alpha antibody in Western blotting, but not with a polyclonal anti-murine TNF-alpha serum. Recombinant fTNF-alpha (rfTNF-alpha) and rfTNF-alpha-GST had a CD50 of 15 ng ml-1 and 230 ng ml-1, respectively, in the L929 cytotoxicity assay. Cats given rfTNF-alpha-GST intravenously manifested the typical biological effects of TNF-alpha, including fever, depression, and piloerection. The rfTNF-alpha-GST upregulated IL-2 receptor and MHC-II antigen expression on peripheral blood mononuclear cells stimulated in vitro, but had no effect on TNF-alpha receptor and MHC-I antigen expression.
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PMID:Cloning, expression and characterization of biologically active feline tumour necrosis factor-alpha. 767 12

Scleritis can be a destructive disease frequently associated with autoimmune disorders. It is believed that primary vasculitis plays an important role in its pathogenesis, but little is known about the cellular effector mechanisms. The purpose of this study was to analyse the inflammatory cellular infiltrate in scleritis. Six episcleral biopsies and two enucleated eyes were studied. The episcleral biopsies were taken from patients with nodular scleritis. In one patient enucleation was done after perforation in anterior necrotising scleritis and, in the other after misdiagnosis of posterior scleritis as intraocular tumour. Morphological criteria and immunohistochemical methods were used to characterise the inflammatory cellular infiltrate. The inflammatory cells infiltrating the episcleral tissue were mainly T lymphocytes and macrophages. There was a predominance of CD4 positive cells, but only few lymphocytes were activated (expressed IL-2 receptor). The cells infiltrating the scleral fibres in the enucleated eyes consisted in both cases predominantly of T cells. Clusters of B cells were found in perivascular areas. In circumscribed areas neutrophils, macrophages, and plasma cells were part of the scleral infiltrate. Signs of a granulomatous process with activated macrophages (epithelioid and giant cells) were present in necrotising scleritis. Expression of major histocompatibility class II molecules (MHC II) was found on lymphocytes and rarely on macrophages. Signs of primary vasculitis were not found in any of the specimens. The cellular infiltrate in scleritis shows, at least at certain stages, features compatible with a T cell mediated (autoimmune) disorder, which may have major therapeutic implications.
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PMID:Cells perpetuating the inflammatory response in scleritis. 802 72

The role of cosignalling in the generation of MHC-unrestricted cytotoxicity of T cells was studied with CD4+ and CD8+ sub-populations highly purified (> 98%) by immunomagnetic cell sorting using OKT4 mab, Dynal anti-CD4 mab, OKT8 mab, Dynal anti-CD8 mab, and OKT3 mab. Cytotoxicity was determined in 4 h cytotoxicity assays against K562 tumor cells known to lack expression of MHC class 1 and class 2 antigens, thus avoiding interference with anti-CD4- or anti-CD8-mediated signalling. Signal transfer was induced via CD4, CD8, CD3, IL-2 receptor and RG receptor specifically interacting with a plant rhamnogalacturonan (RG). In CD8+ cells, the first signal delivered by the sorting mab (immobilized OKT8 or Dynal anti-CD8 or OKT3) only induced low MHC-unrestricted cytotoxicity but committed the cells to develop largely enhanced cytolytic potential upon stimulation with a second (IL-2 or RG) or third (OKT3, IL-2, RG) signal. The highest cytolytic potential was achieved by cumulative signalling via CD8, CD3, IL-2 receptor and RG receptor. The generation of MHC-unrestricted cytotoxicity of CD8+ cells correlated with increased effector cell/target cell conjugate formation. In CD4+ cells, OKT4 as sorting mab induced very low cytolytic potential, and a moderate committment to IL-2 signals but a stronger one to RG signals, yielding further cytotoxicity enhancement. The highest cytolytic potential was obtained by cumulative signalling via CD4, IL-2 receptor and RG receptor. Dynal anti-CD4 mab was inefficient and OKT3, as sorting mab of CD4+ cells from CD8-depleted PNAC, appeared to block subsequent OKT4-induced generation of MHC-unrestricted cytotoxicity by delivering a negative signal. Immobilized OKT3 as second signal present in cultures of OKT4-sorted CD4+ cells was inefficient. Surprisingly, soluble OKT3 together with IL-2 delivered a positive signal in cultures of OKT4-sorted CD4+ cells.
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PMID:Signal requirement for induction of MHC-unrestricted antitumor cytotoxicity of human T cell CD4+/CD8+ subpopulations. 807 98

When DBA/2 mice are inoculated both intraperitoneally (i.p.) and subcutaneously (s.c.) with syngeneic SL2 lymphoma cells and treated i.p. on day 10-14 with 20,000 units IL-2/day, about 50% of the mice reject both the ascitic tumour and the s.c. tumour. During IL-2 therapy large areas of necrosis appear in the solid SL2 tumours between day 12 and 15. Immunohistochemical studies show that only a small number of infiltrating cells is present in the tumours. The percentage of macrophages (MHC-II+) in the tumours is about 1 and the percentage of T-lymphocytes (alpha beta-TCR+) about 0.5. No differences in the numbers of infiltrating cells are seen in untreated and IL-2 treated tumour bearing mice. The tumour surrounding infiltrate consists mainly of mononuclear cells: about 50% macrophages, 20% CD8+ cells, and 15% CD4+ cells. No tumour-infiltrating cells were found that express the IL-2 receptor. We conclude that direct cytotoxic activity of tumour infiltrating cells cannot account for the rapid occurrence of necrosis. When L3T4+ cells were eliminated by treating the mice with alpha-L3T4 monoclonal antibodies before tumor inoculation and treatment with rIL-2, tumor eradication did not occur. So, L3T4+ helper T-cells are essential for IL-2-mediated tumour regression. Exogenous rIL-2 is not directly responsible for the induced tumour regression. A significant stagnation of intratumoural bloodflow is observed after histological analysis; yet it still needs to be determined whether this is the primary cause or consequence of the observed necrosis.
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PMID:Histological analysis of IL-2 induced regression of murine solid SL2-tumors. 810 52

Using a recently developed murine model of haematogenously induced Staphylococcus aureus, the authors have characterized the phenotypes and functional properties of inflammatory cells present in the synovium of arthritic mice. The results show that large numbers of granulocytes and macrophages were observed in the inflamed synovia within 24 h of inoculation of S. aureus strain LS-1. Many of the synovial macrophage-like cells strained for cytoplasmic IL-1 alpha and TNF-alpha. Subsequently (> or = 48 h later), a prominent infiltration of T lymphocytes, predominantly of CD4+ phenotype, was observed. Some of the T lymphocytes stained for IL-2 receptor and intracytoplasmic interferon-gamma (IFN-gamma). Surprisingly, in spite of the severe inflammatory process, very few cells expressed MHC class-II molecules in the arthritic synovia. In addition, in vivo depletion of CD4+ T-cells resulted in a considerably milder course of staphylococcal arthritis. The similarities in the phenotype expression of synovial cells and central role of T-cells in S. aureus arthritis as well as in non-infectious models of arthritis, indicate that the process governing joint destruction is likely to be the same, irrespective of the initial stimulus.
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PMID:Role of T lymphocytes in experimental Staphylococcus aureus arthritis. 814


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