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

Adherent cells from HIV-infected subjects as well as in vitro HIV-infected normal adherent cells produce spontaneously a 29-kD (p29) factor that inhibits mitogen-induced proliferation of normal T cells. p29 mediates a partial dose-dependent inhibition of total protein synthesis in both nonstimulated and PHA-activated cells that is associated with impaired PHA-induced expression of IL-2 receptor (IL-2R)alpha chain, HLA-class II molecules, and production of IL-2 by these cells; conversely, p29 does not modify the expression of IL-2R beta chain, 4F2, CD9, or transferrin receptor, or the production of IL-1 and TNF alpha by the cells. 1 h preincubation of the cells with p29 is sufficient to detect its biologic activity and added rIL-2 abrogates p29-induced inhibition of IL-2R alpha chain expression; however, p29 does not display any biologic effect on already expressed IL-2R alpha chains. The impaired expression of IL-2R alpha chain mediated by p29 is not due to a decreased accumulation of the corresponding mRNA transcripts, but is associated with a two-fold increase of intracellular cAMP. Binding experiments with 125I-rIL-2 reveals that p29 induces a 50% decrease in the number of both high and low affinity IL-2R per cell. p29 also inhibits alloantigen-induced proliferation of PBMC, whereas it does not modify IL-2-dependent proliferation of 48-h PHA-blasts that already express high affinity IL-2R. These findings indicate that p29 mediates its biologic activity during early stages of T cell activation affecting the expression of high affinity IL-2R and production of IL-2, through a nontranscriptional mechanism involving an increase of intracellular cAMP.
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PMID:Human immunodeficiency virus-infected adherent cell-derived inhibitory factor (p29) inhibits normal T cell proliferation through decreased expression of high affinity interleukin-2 receptors and production of interleukin-2. 132 45

Quiescent T cells can be induced to express many genes by mitogen or antigen stimulation. The messenger RNAs of some of these genes undergo relatively rapid degradation compared to messenger RNAs from constitutively expressed genes. A T cell activation pathway that specifically regulates the stability of messenger RNAs for the lymphokines interleukin-2, interferon-gamma, tumor necrosis factor-alpha, and granulocyte-macrophage colony-stimulating factor is induced by stimulation of the CD28 surface molecule. This pathway does not directly affect the steady-state messenger RNA level, transcription, or messenger RNA half-life of other T cell activation genes, including c-myc, c-fos, IL-2 receptor, and the 4F2HC surface antigen. These data show that stimuli received at the cell surface can alter gene expression by inducing specific changes in messenger RNA degradation.
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PMID:Regulation of lymphokine messenger RNA stability by a surface-mediated T cell activation pathway. 254 May 28

T cells can be divided into unprimed virgin (T0) and primed memory (T') subpopulations by their expression of different isoforms of the leukocyte common antigen. We have separated the CD4+ T cells into T0 and T' subpopulations and examined their capacity to respond to activation signals via the CD2 receptor molecule. On stimulation with a mitogenic combination of anti-CD2 antibodies, the T' population was induced to express IL-2 receptor, increased levels of the 4F2 antigen and to proliferate, whereas the response of the T0 populations was reflected solely by a minimal increase in the 4F2 antigen. The addition of IL-2 or monocytes to T0 cells stimulated with anti-CD2 antibodies did not enhance their expression of the IL-2 receptor or proliferation. However, T0 cells stimulated with the triad of anti-CD2 antibodies, monocytes, and IL-2 responded with high levels of IL-2 receptor expression and proliferation. The T0 subpopulation could also be induced to respond when cultured with anti-CD2 antibodies and phorbol myristate acetate. The results suggest that in order to respond to stimulation via the CD2 molecule, virgin T helper cells require additional signals that can be jointly provided by monocytes and IL-2. In contrast, memory T helper cells can be activated via CD2 signal transduction alone.
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PMID:Virgin and memory T cells have different requirements for activation via the CD2 molecule. 257 87

The activation state of thymic T and B lymphocytes was phenotypically and functionally explored in patients with Myasthenia Gravis (MG). We detected no phenotypic signs of activation in fresh total thymic lymphocyte suspensions (CD25 expression) while functional signs of activation were reflected by a significantly higher sensitivity to recombinant IL-2 (rIL-2) without any previous stimulation in MG patients as compared to controls. The response to rIL-2 was time-and dose-dependent, was inhibited by a blocking anti-IL-2 receptor antibody, and was associated to an increase of CD25+ T cells. Thymic B-cell populations purified after T cell and macrophage depletion, expressed at variable levels activation markers such as the transferrin receptor, the CD25, 4F2, CD23 and B8.7 Ag, indicating that a marked proportion of them are activated. Moreover, these B-cell populations were spontaneously sensitive to BCGF-12-kD and to a lesser extent to rIL-2, demonstrating that they also exhibit functional signs of activation. The largest proportion of activated B cells and the most intense response to BCGF-12-kD was found in patients presenting the highest anti-acetylcholine receptor (AChR) titers. Our data confirm the hyperactivity of the thymus gland in MG, reflected by the presence of T and B cells with functional signs of pre-activation. These cells could conceivably be located in lymphoid follicles and may represent autoreactive cells involved in the autoimmune process. Whether they are sensitized to AChR remains to be investigated.
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PMID:B- and T-cell activation in the thymus of patients with myasthenia gravis. 262 39

Heat-inactivated (45 degrees C/1 hr) lymphocytes selectively activate suppressor T cells in the mixed lymphocyte reaction (MLR), while no significant proliferation and cytotoxic T lymphocyte activation can be detected. It is not well understood why hyperthermic treatment abolishes the stimulatory capacity of lymphocytes since HLA-DR molecules remain detectable immediately following heat exposure. In order to further characterize the requirements for Ts activation we studied the effects of hyperthermic treatment on cellular protein and DNA synthesis and cell surface protein expression in proliferating T and B cells; interleukin (IL)-1, IL-2, and IL-3 release following allogeneic stimulation with heat treated cells (HMLR); and IL-2 receptor expression as an indicator of T cell activation in the HMLR. Hyperthermic treatment reduced cellular protein synthesis as estimated by 14C-leucine uptake to about 15%, and DNA synthesis (3H-thymidine incorporation) to about 5% of untreated control cells. In contrast to y-irradiated cells, viability of heated cells rapidly declined within the first 24 hr. Hyperthermic treatment doubled binding of mouse immunoglobulin paralleled by an increased expression of IL-2 and transferrin receptors, while expression of HLA-DR and 4F2 proteins appeared unchanged. Stimulation with heated cells triggered the release of IL-1- and an IL-3-like bioactivity but did not induce IL-2 synthesis and/or release, thus explaining the lack of proliferation in the HMLR. Addition of exogenous IL-2 but not IL-1 restored HMLR proliferation. A comparison of allostimulation with y-irradiated and heat-treated cells revealed that significantly fewer T cells were induced to express IL-2 receptors at day 3 (14% vs. 8%, P less than 0.001) and at day 6 (42% vs. 21%, P less than 0.05) with heat-inactivated stimulators. We conclude that metabolically compromised lymphocytes activate Ts and are sufficient to stimulate IL-1 and IL-3 synthesis but do not transmit an unknown signal required for the activation of IL-2 synthesis and IL-2 receptor expression on a yet-to-be-defined T cell subset.
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PMID:Differential effect of gamma-irradiated and heat-treated lymphocytes on T cell activation, and interleukin-2 and interleukin-3 release in the human mixed lymphocyte reaction. 296 Nov 13

We studied the expression of early activation antigens (4F2, transferrin receptor, IL-2 receptor) on peripheral lymphocytes (PBL) of patients with Crohn's Disease. We have found that the proportion of PBL expressing these antigens was significantly higher in patients than in controls. The expression of the 4F2 antigen was more pronounced than that of other activation antigens directly involved in promoting cell growth (e.g. transferrin receptor, IL-2 receptor). These results indicate that CD patients have an increased number of T cells in a very early phase of activation.
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PMID:T cell early activation antigens expressed by peripheral lymphocytes in Crohn's disease. 298 88

Expression of the activation-associated 4F2 antigen, transferrin receptor and interleukin-2 (IL-2) receptor on suspended cells from 75 biopsied low-grade non-Hodgkin lymphomas (L-NHL) of B-cell origin was correlated to patient survival, clinical prognostic parameters and estimated DNA synthesis. 4F2 antigen expression correlated significantly with poor patient survival, high DNA synthesis and transferrin receptor expression. Transferrin receptor expression was associated with high DNA synthesis and treatment response, but not with patient survival. On the other hand, IL-2 receptor was correlated neither to patient survival nor to other studied markers for cell activation, but seemed to be expressed on certain subsets of lymphomas. We suggest that monoclonal antibody (MAb) against the activation-associated 4F2 antigen could be used to select patients with L-NHL for aggressive chemotherapy.
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PMID:The activation-associated antigen 4F2 predicts patient survival in low-grade B-cell lymphomas. 310 47

Tumor cells from 5 human B cell non-Hodgkin's lymphoma (B-NHL) patients were investigated for proliferative activity and idiotypic (Id+) immunoglobulin (Ig) secretion in serum-free medium without deliberate addition of B cell growth or differentiation factors (BCDF). These data were compared with cell surface marker expression, notably of activation antigens such as 4F2 and interleukin-2 (IL-2) receptor. Cells from all patients became 4F2 positive at the end of the 6-day culture period. Freshly drawn cells from 3 out of 5 patients expressed the IL-2 receptor (CD25; Tac antigen) or acquired this marker during culture in vitro and secreted relatively high levels of Id+ Ig in vitro. This correlated with elevated serum Id levels (greater than or equal to 0.5 micrograms/ml in vitro versus greater than or equal to 20 micrograms/ml in vivo). In the 2 CD25 (Tac)- B-NHL patients serum Id levels were below the detection limit and the amount of Id+ Ig secreted in vitro did not surpass 50 ng/ml. Only the B-NHL cells from a single patient were initially CD25 (Tac) positive and only these cells proliferated in serum-free culture. To test whether IL-2 receptor expression in the 3 CD25 (Tac)+ patients was functional, recombinant IL-2 (rIL-2) either alone or in conjunction with BCDF and recombinant IL-4 (rIL-4) was added to the cultures. In 2 out of 3 CD25 (Tac)+ patients rIL-2 was capable of enhancing proliferation or Ig secretion. In addition rIL-2 was found to enhance BCDF-mediated but not rIL-4 mediated responses. The third CD25 (Tac)+ B-NHL population was resistant to any of these lymphokines. Thus, this serum-free culture system may accurately reflect patient serum Id levels. IL-2 appears to regulate not only the in vitro but also the in vivo Ig secretion by neoplastic B cells.
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PMID:Idiotypic immunoglobulin secretion by human B cell non-Hodgkin's lymphomas is related to the expression of the interleukin-2 receptor. 312 22

Three previously selected monoclonal antibodies (mAb) directed against the clonotypic structure of a variant (termed JA3) of the interleukin 2 (IL-2)-producing Jurkat leukemia cell line (anti-JTi1-3 mAb) were found to induce an adherent cell-dependent proliferation of peripheral blood T cells in 20 different donors. Unlike the early cell proliferation induced by anti-T3 mAb, anti-JTi mAb-induced proliferation was detectable at day 5-6 of culture and reached peak levels at day 7-9. Less than 1% JTi+ cells were consistently detected in the starting peripheral blood lymphocytes or in control cultures in which cells were stimulated with anti-T3, phytohemagglutinin, or allogeneic cells. However, JTi+ cells were found in increasing proportions after culture with anti-JTi mAb and they were mostly represented by large blast cells expressing either the T4 or the T8 antigen, together with typical activation antigens including HLA-DR, IL-2 receptor, and 4F2. Immunoprecipitation experiments and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that anti-JTi-reactive molecules present on antibody-stimulated lymphocytes or on JA3 cells were similar, disulphide-linked heterodimeric structures.
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PMID:Anticlonotypic monoclonal antibodies induce proliferation of clonotype-positive T cells in peripheral blood human T lymphocytes. Evidence for a phenotypic (T4/T8) heterogeneity of the clonotype-positive proliferating cells. 387 4

Antigen-specific, interleukin 2 (IL-2)-dependent human T-cell lines and clones were utilized to study the relationship between IL-2 receptor expression and antigenic stimulation. T cells that had not been exposed to antigen for 2 wk or more expressed a stable low level of the IL-2 receptor. After reexposure to antigen, a 10- to 30-fold increase in the level of the IL-2 receptor was rapidly induced, with the peak level of IL-2 receptor expression occurring at 15-30 hr. This peak preceded the peak in cell proliferation [( 3H]thymidine incorporation), which was at 48-72 hr. Within 2-14 days after peak IL-2 receptor expression, it returned to a low base-line level. The transient elevation in IL-2 receptor level was antigen specific because it occurred in response to specific allogeneic stimulator cells but not after exposure to cells expressing irrelevant HLA allotypes. The levels of other cell-surface proteins, including those related to T-cell activation (HLA-DR, T10, 4F2, A-1A5) as well as T3, which has been proposed to be a component of the T-cell receptor complex for antigen, did not change in response to antigen exposure or deprivation. Because IL-2 was maintained at a consistently high level throughout these experiments, the antigen-induced changes in the IL-2 receptor appear to be independent of changes induced by IL-2 itself. Both cloned T cells and mixed populations containing T4 and T8 subsets showed similar IL-2 receptor responsiveness, indicating that this finding is generalizable to most, if not to all, antigen-responsive T cells.
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PMID:Antigenic stimulation regulates the level of expression of interleukin 2 receptor on human T cells. 642 28


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