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

Recombinant human interleukin-4 (rhIL-4) and transforming growth factor-beta 1 (TGF-beta 1) suppressed the induction of lymphokine-activated killer (LAK) activity induced by recombinant human interleukin-2 (rhIL-2) in peripheral blood lymphocytes. DNA synthesis and the expression of the p55 alpha chain of the IL-2 receptor (Tac antigen) were also inhibited. The inhibitory effect was greatest when these factors were added during the first 48 h of a 4-day culture, with reduced cytolytic activity against both natural killer (NK) resistant and NK-sensitive tumour cell line targets. The suppressive action of both cytokines was accompanied by a reduction in tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) levels in lymphocyte culture supernatants. Recombinant human IFN-gamma (rhIFN-gamma), but not recombinant human TNF-alpha (rhTNF-alpha) was able to overcome the inhibitory effect of recombinant human interleukin-4 (rhIL-4) on LAK induction and DNA synthesis but not Tac antigen expression. However, cytotoxicity induced by rhIFN-gamma alone was also suppressed by rhIL-4 and TGF-beta 1, inferring that rhIFN-gamma-mediated abrogation of rhIL4 suppression was not simply a direct IL-2-independent effect on cytotoxicity. In addition, rhIL-4 did not increase TGF-beta production from rhIL-2-activated peripheral blood mononuclear cells, suggesting that rhIL-4 did not mediate reduction of rhIL-2 responses through the induction of TGF-beta release.
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PMID:Suppression of lymphokine-activated killer (LAK) cell induction mediated by interleukin-4 and transforming growth factor-beta 1: effect of addition of exogenous tumour necrosis factor-alpha and interferon-gamma, and measurement of their endogenous production. 212 61

Lymphokine-dependent T cell proliferation is regulated in part by the cell surface expression of high affinity interleukin-2 receptors (IL-2R). The functional, high affinity form of the IL-2 receptor is comprised of two ligand binding components, IL-2R alpha (Tac, p55) and IL-2R beta (p70/75). In the absence of the other subunit, IL-2R alpha and IL-2R beta bind ligand with only low or intermediate affinity, respectively. The inducible and transient expression of IL-2R alpha regulates the display of high affinity receptors, while IL-2R beta appears to contribute importantly to growth signal transduction. Although the primary structure of both receptor chains has now been elucidated, the mechanism of growth signal transduction through the high affinity IL-2R remains undefined. Of note, IL-2R beta belongs to a novel family of cytokine receptors including the binding proteins for IL-3, IL-4, IL-6, erythropoietin, and granulocyte-macrophage colony-stimulating factor. These various receptors may well utilize a common intracellular signalling pathway.
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PMID:The human interleukin-2 receptor: insights into subunit structure and growth signal transduction. 212 4

The human allogeneic mixed lymphocyte reaction is the in vitro correlate of graft rejection. Cytotoxic effector cells generated during an allogeneic mixed lymphocyte reaction were previously shown to express the human p55 IL-2 receptor subunit, whereas resting cells do not express this receptor peptide. In this study, we asked whether Pseudomonas exotoxin or bismuth-212 (an alpha-particle emitting radionuclide) coupled to the anti-IL-2 receptor mAb, anti-Tac, were able to selectively eliminate alloresponsive cells generated during an allogeneic mixed lymphocyte reaction. After assembly, anti-Tac immunoconjugates retained their binding integrity, specificity, and selectivity. Deletion of alloresponsive cells was shown by the removal of alloproliferating cells as assessed by quantitating cell recovery and by measurement of thymidine incorporation into newly synthesized DNA. Both toxin and radionuclide immunoconjugates eliminated established cytotoxic effector cells generated in an allogeneic mixed lymphocyte reaction, while leaving intact the PHA-inducible mitogenic response of the nonactivated cells. The addition of excess anti-Tac blocked all of the effects of these cytotoxic reagents. The therapeutic reagents in vitro were most effective when added just prior to the peak of the alloproliferative response, when receptor expression would be close to maximum. Thus, anti-Tac conjugated either with toxin or radionuclide is effective in vitro in specifically eliminating cytotoxic effector cells.
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PMID:Selective elimination in vitro of alloresponsive T cells to human transplantation antigens by toxin or radionuclide conjugated anti-IL-2 receptor (Tac) monoclonal antibody. 213 54

The majority of human NK cells express low affinity IgG Fc receptors (CD16+), whereas a minor subset of NK cells lack Fc receptor expression (CD16-). In contrast to CD16+ NK cells that express only p75 IL-2 receptors, CD16- NK cells constitutively co-express both p75 and p55 IL-2 receptors in vivo and preferentially respond to low concentrations of IL-2 with increased cytolytic activation and proliferation. Scatchard analysis demonstrated the presence of approximately 1,200 high affinity (approximately 25 pM kD) and approximately 9,600 intermediate affinity (approximately 2 nM kD) IL-2 receptors on CD16- NK cells. CD16+ NK cells expressed only a single intermediate affinity IL-2 receptor of approximately 1.9 nM kD (approximately 9,000 sites per cell). The IL-2 binding data thus substantiated the phenotypic and functional studies and definitively show that the differential responsiveness of CD16- and CD16+ NK cells to IL-2 is manifested through different affinity IL-2 receptors.
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PMID:Constitutive expression of high affinity interleukin 2 receptors on human CD16-natural killer cells in vivo. 213 97

Infection of mice with lymphocytic choriomeningitis virus (LCMV) produces a rapidly induced immuno-suppression manifested by low lymphocyte proliferation in response to lipopolysaccharide (LPS) and concanavalin A (ConA). Analysis of the mechanisms underlying the unresponsiveness to these mitogens was undertaken at the cellular and molecular levels 7 days after infection. The selective elimination of CD8+ T cells and the results of coculture experiments demonstrated that unresponsiveness was not due to suppressor cells. Similarly, the role of inhibitory factors such as prostaglandins was excluded, since indomethacin, which inhibits their production, did not reverse the unresponsiveness. Analysis of different cytokines secreted by ConA-activated macrophages or T cells revealed that interleukin-1 (IL-1), synthesized during the T-dependent activation of macrophages by ConA, was normally produced by cells from LCMV-infected mice. In contrast, IL-2, which is produced by activated CD4+ T cells, was undetectable. Addition of exogenous IL-2 did not restore the proliferative response, although the p55-kilodalton protein of the IL-2 receptor was induced by ConA on CD4+ cells from LCMV-infected mice. Our results can be interpreted as showing that (i) unresponsiveness to mitogens of cells from LCMV-infected mice is not due to altered functions of the macrophages with respect to IL-1 production; (ii) CD4+ cells are activated, since the p55 chain of the IL-2 receptor is induced; (iii) the lack of IL-2 production cannot explain T-cell unresponsiveness, since addition of exogenous IL-2 did not restore the proliferative response. Taken together, these data suggest that T-lymphocyte unresponsiveness should be related to an inherent proliferative defect subsequent to T-cell activation and IL-2 receptor expression.
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PMID:Lymphocytic choriomeningitis virus-induced immunodepression: inherent defect of B and T lymphocytes. 214 39

We studied the role of Fc receptors and interleukin-2 (IL-2) receptor subunits in anti-CD3 monoclonal antibody (MAb)-mediated cytotoxicity of CD3+ leukemic large granular lymphocytes (LGL). Peripheral blood mononuclear cells from four patients with CD3+ LGL leukemia were cultured with 1 microgram/ml of anti-CD3 MAb. Anti-CD3 MAb-mediated cytotoxicity was not inhibited when K562 target cells were preincubated with heat-aggregated human IgG, suggesting that binding of the effector cell-bound anti-CD3 MAb to Fc receptors of target was not involved in cytotoxicity. Induction of cytotoxicity was not blocked by the addition of either anti-p55 or anti-p75 IL-2 receptor MAbs. These results show that the induction of cytotoxicity by anti-CD3 MAb is not mediated through IL-2 receptor subunits in CD3+ leukemic LGL.
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PMID:Interleukin-2 receptor monoclonal antibodies have no effect on anti-CD3 monoclonal antibody-mediated cytotoxicity in CD3+ leukemic large granular lymphocytes. 214 89

We studied the role of interleukin-2 (IL-2) receptor subunits in the activation of leukemic CD3+ large granular lymphocytes (LGL). Peripheral blood mononuclear cells from four patients with CD3+ LGL leukemia were activated with 500 mu/ml of recombinant IL-2. Induction of both proliferative and cytotoxic functions by IL-2 was blocked by addition of anti-p75 IL-2 receptor monoclonal antibody, but not by addition of anti-p55 IL-2 receptor monoclonal antibody. Sorting experiments demonstrated directly that the effects of the anti-p75 IL-2 receptor monoclonal antibody were on leukemic LGL. These results show constitutive expression of functional p75 IL-2 receptors on leukemic LGL and suggest a possible mechanism for leukemic LGL proliferation in vivo.
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PMID:Activation of leukemic large granular lymphocytes by interleukin-2 via the p75 interleukin-2 receptor. 214 47

Thymocyte cell suspensions, prepared from mice at different ages, were cultured in vitro with human rIL-2. This stimulation resulted in a cell population that contained almost 50% TCR-gamma delta-positive cells if thymocytes were taken from fetal day 17 until just after birth. Analysis of the variable (V gamma) region used by the TCR-gamma delta cells revealed that 90% of them expressed TCR-V gamma 3, and less than 5% expressed TCR-V gamma 2. Cells positive for TCR-alpha beta were barely detectable. If fetal day 18 organ cultured thymus lobes, instead of a cell suspension, were stimulated with IL-2, no rise in the number of TCR-V gamma 3+ or TCR-delta+ cells was observed, whereas a partial outgrowth of TCR-alpha beta+ cells occurred. From day 1 after birth, the number of TCR-gamma delta cells recovered from an IL-2-stimulated thymocyte cell suspension dropped to reach a plateau of 15% of the total cell number, whereas TCR-V gamma 3+ cells became undetectable in older animals. TCR-alpha beta+ cells, on the other hand, quickly rose in cell number after birth. Kinetic analysis showed that the preferential outgrowth of TCR-V gamma 3+ cells in IL-2-stimulated fetal day 18 thymocyte cell suspensions was present from the onset of the culture; a significant proliferation of CD4 or CD8 single positive TCR-alpha beta cells was never observed. This lack of proliferation of TCR-alpha beta cells was not due to inhibition by the activated TCR-V gamma 3+ cells. Throughout the IL-2 culture, one-fourth of the TCR-V gamma 3+ thymocytes was positive for CD8. Analysis of the DNA content and the IL-2 receptor (IL-2R) p55 expression showed that during the first days of culture the TCR-V gamma 3+ cells had a much higher proliferation rate than the TCR-V gamma 3- cells, although TCR-V gamma 3+ IL2R p55+ cells could not be detected. From day 3 to 4 of culture, the proliferation rate of TCR-V gamma 3+ cells equaled that of the rest of the cells and less than 20% of the TCR-V gamma 3+ cells expressed the IL-2R p55. The biologic significance of our findings is discussed.
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PMID:Preferential proliferation of T cell receptor V gamma 3-positive cells in IL-2-stimulated fetal thymocytes. 214 32

A human T-leukaemic cell line, HSB.2-C5B2, which produces high levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) when stimulated with phytohaemagglutinin (PHA) plus IL-1, was recloned to obtain spontaneous variants in IL-2 production in response to the stimuli. In these subclones, the ability of one clone to produce IL-2 correlated well with that to produce IFN-gamma. Three C5B2 subclones: clone no. 28, a high IL-2 producer, clone no. 61, an intermediate IL-2 producer, and clone no. 40, a non-producer, were selected and examined for differences in signal transduction mechanisms. Since the three subclones were shown to express about the same number of IL-1 binding sites with similar affinities, the loss of ability to produce IL-2 was not due to decreased cell-surface receptor or changes in receptor property. In support of this, IL-1 induced expression of the IL-2 receptor (Tac/p55 antigen) to the same extent on the three subclones. The levels of conventional intracellular second messengers were compared and it was revealed that loss of responsiveness was closely related to the subclones' degree of (poly)phosphoinositide (PI) turnover, protein kinase C (PKC) activation and cyclic AMP formation in response to PHA. Moreover, resting intracellular cyclic AMP concentrations were found to be increased in subclones with attenuated IL-2 production. These results indicate that the variation of IL-1-induced production of IL-2 and IFN-gamma in this T-cell line is attributed to the difference in the PHA-mediated signal transduction pathway and, presumably, to the different regulation of intracellular cyclic AMP.
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PMID:IL-1-induced production of IL-2 and IFN-gamma in subclones of human T-cell derived leukaemia HSB.2 cells: regulation by phytohaemagglutinin-mediated (poly)phosphoinositide breakdown and cyclic AMP. 217 58

The role of previously defined thymocyte (Thm) growth factors in interleukin (IL)-7-induced Thm growth has not been fully elucidated. Therefore, experiments were designed to examine the capacity of IL-7 to: (i) directly induce Thm proliferation in the absence of experimental and known physiologic costimulators of Thm mitogenesis, and (ii) synergize with other Thm growth factors in supporting Thm proliferation. The data indicate that IL-7 is directly mitogenic for Thm; that is, IL-7 induces Thm proliferation in the absence of experimental comitogens such as concanavalin A, phytohemagglutinin, and phorbol myristate acetate and in the presence of neutralizing antibodies to murine IL-1 alpha, IL-1 beta, IL-2, IL-2 receptor (IL-2R)(p55), IL-2R(p70), IL-4, IL-6, and tumor necrosis factor (TNF). We also tested previously described Thm growth factors, i.e., IL-2, IL-4, IL-6, and TNF-alpha, for the capacity to synergize with IL-7 in Thm growth. Our results indicate that IL-2, IL-6, and TNF-alpha, but not IL-4, synergize with IL-7 in supporting Thm proliferation. These data suggest that IL-7 functions alone and in a synergistic fashion with other cytokines to regulate Thm growth.
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PMID:Synergism of interleukin 7 with the thymocyte growth factors interleukin 2, interleukin 6, and tumor necrosis factor alpha in the induction of thymocyte proliferation. 218 44


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