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)

The high affinity form of the human IL-2 receptor (IL-2R) has two known components, the IL-2R alpha (p55) and the IL-2R beta chain (p75). We have previously shown that recombinant IL-2 (rIL-2) could induce the expression of the alpha-chain (p55) on T cells and thymocytes, and increase this expression following suboptimal activation with concanavalin A (Con A) in combination with IL-2. An increase in the accumulation of IL-2R alpha-specific mRNA induced by rIL-2 in T cells and thymocytes had also been documented. We report here that the expression of IL-2R beta on the cell surface can be demonstrated on human thymocytes by the binding of Mik beta1, a MoAb directed against an epitope of the beta-chain. The IL-2R beta chain is constitutively expressed on freshly isolated thymocytes; this expression can be increased in thymocytes activated with Con A in combination with IL-2 or tetradecanoylphorbol 13-acetate (TPA). Blocking the formation of high affinity receptors with a MoAb directed against the alpha-chain of the receptor results in an increase in the display of IL-2R beta as evidenced by binding of MoAb Mik beta1. The accumulation of IL-2R-beta-specific mRNA is observed in freshly isolated thymocytes and it is increased in thymocytes cultured with rIL-2 alone, with Con A, and further enhanced by the addition of rIL-2 in combination with Con A or with TPA. Cyclosporine (CsA), which inhibits the accumulation of lymphokine-specific mRNA of thymocytes, does not inhibit the induction of the accumulation of IL-2R beta-specific mRNA. This is analogous to its effect on the expression of the alpha-chain (p55), and the accumulation of alpha-chain-specific mRNA.
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PMID:Regulation of IL-2 beta receptor expression and beta-chain mRNA by human thymocytes. 173 30

Interleukin 2 (IL-2) is a potent immunostimulant that causes the release of secondary cytokines and the production of lymphokine-activated killer cells. We investigated the cellular and cytokine responses to injection of recombinant human IL-2 into the human cerebrospinal fluid of 11 patients with metastatic tumors involving the spinal or cerebral leptomeninges. After initial intraventricular IL-2 administration (1.25 x 10(5) to 2 x 10(6) Cetus units/injection), cerebrospinal fluid samples were collected at intervals from 0 to 24 h. Enzyme-linked immunosorbent assay results indicated that IL-2 levels gradually decreased during the first 24 h, with an average t1/2 between 4 and 8 h. Induction of tumor necrosis factor alpha, interleukin 1 beta, interleukin 6, gamma-interferon, and interleukin 2 receptor (p55) was also assessed by enzyme-linked immunosorbent assay. Tumor necrosis factor alpha and interleukin 6 levels peaked at 2 to 4 h and 4 to 6 h, with concentrations between 71 to 1,714 pg/ml and 942 to 10,500 pg/ml, respectively. Interleukin 1 beta, gamma-interferon, and soluble IL-2 receptor peaked later, during 6 to 12 h; the levels achieved were 234 pg/ml, 25 NIH units/ml, and 207 units/ml, respectively. All cytokine concentrations returned to near baseline between 12 and 24 h; however, the soluble IL-2 receptor levels remained elevated. Additional observations included a rapid influx of neutrophilic leukocytes, followed by a prolonged presence of lymphocytes. These data indicate a broad and complex potential of the immune response in the central nervous system, as well as further define the cytokine cascade in response to IL-2 alone.
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PMID:Cytokine responses to intraventricular injection of interleukin 2 into patients with leptomeningeal carcinomatosis: rapid induction of tumor necrosis factor alpha, interleukin 1 beta, interleukin 6, gamma-interferon, and soluble interleukin 2 receptor (Mr 55,000 protein). 173 71

Interleukin 2 (IL-2) has been shown to stimulate tyrosine phosphorylation of a number of proteins requiring only the p75 beta chain of the IL-2 receptor. Unlike the receptors for epidermal growth factor, insulin, and other growth factors, the p55-alpha and p75-beta chains of the IL-2 receptor have no tyrosine protein kinase domain suggesting that the IL-2 receptor complex activates protein kinases by a unique mechanism. The activation of tyrosine kinases by IL-2 in situ was studied and using a novel methodology has shown tyrosine kinase activity associated with the purified IL-2R complex in vitro. IL-2 stimulated the in situ tyrosine phosphorylation of 97 kDa and 58 kDa proteins which bound to poly(Glu,Tyr)4:1, a substrate for tyrosine protein kinases, suggesting these proteins had characteristics found in almost all tyrosine kinases. IL-2 was found to stimulate tyrosine protein kinase activity in receptor extracts partially purified from human T lymphocytes and the YT cell line. Biotinylated IL-2 was used to precipitate the high-affinity-receptor complex and phosphoproteins associated with it. The data indicated that the 97-kDa and 58-kDa phosphotyrosyl proteins were tightly associated with the IL-2 receptor complex. These proteins were phosphorylated on tyrosine residues by IL-2 stimulation of intact cells and ligand treatment of in vitro receptor extracts. Furthermore, the 97-kDa and 58-kDa proteins were found in streptavidin-agarose/biotinylated IL-2 purified receptor preparations and showed high affinity for tyrosine kinase substrate support matrixes. The experiments suggest that these two proteins are potential candidates for tyrosine kinases involved in the IL-2R complex signal transduction process.
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PMID:Regulation of the interleukin 2 receptor complex tyrosine kinase activity in vitro. 175 80

Recently, we have shown that soluble factors released by human lymphocytes after lectin stimulation could increase the contractile tension of rat atria "in vitro" and that interleukin-2 (IL-2) could be part of this reaction. The effect of IL-2 was potentiated by the Ca2+ ionophore A23187 or free arachidonic acid (AA). In this study we demonstrate that the action of IL-2 can be prevented by pre-incubation of the heart tissue with monoclonal anti-IL-2 receptor (anti-p55), suggesting that binding to the IL-2 receptor is necessary for the induction of the biologic effect. In the presence of A23187 or AA, the effect of the synthetic diacylglyceride oleoyl-acetyl-glycerol (OAG) was similar to that of IL-2. Elimination of phospholipase C activity by pre-incubation of the atria with 2-nitro-carboxyphenyl,N,N'-diphenylcarbamate (NCDC) abrogated the effects of IL-2 in the presence of A23187 or AA, but was ineffective when OAG + A23187 or OAG + AA was used. Inhibition of atrial phospholipase A2 activity with p-bromo-phenacylbromide (BPB) blocked the response of atria to either IL-2 + A23187 or OAG + A23187 but was not effective when AA was used as second signal (IL-2 + AA or OAG + AA). Both the OAG and the IL-2 positive inotropic effects could be prevented by the protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine (H7) but were poorly inhibited by N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA1004), an inhibitor of the cyclic nucleotide-dependent protein kinases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Positive inotropic effect of interleukin-2. Role of phospholipases and protein kinase C. 178 63

A continuous cloned cell line (Y479) was established by culturing normal mouse spleen cells in a high concentration of interleukin-2 (IL-2). Y479 cells showed morphological characteristics of large granular lymphocyte with the phenotypes of Thy-1.2+, T3+, Lyt-1-, Lyt-2-, L3T4-, B220-, AsGM1+, LFA-1+, and TcRV beta 8-. The Y479 cells required a high concentration of IL-2 for their growth but did not express detectable p55 IL-2 receptor (IL-2R) although they bound IL-2 with high and low affinities. Analysis of the IL-2 binding proteins on the Y479 cells revealed that both the high and low affinity receptors consisted only of 70 kDa protein. Analysis of the 70 kDa protein was performed using five monoclonal antibodies (L15, L20, L23, L34, and L61) against human recombinant IL-2. Although they recognized different epitopes, all monoclonal antibodies immunoprecipitated 70 kDa IL-2R that was cross-linked with radioiodinated IL-2. The supernatant after immunoprecipitation with L61 still contained IL-2/IL-2R complex that was L23-reactive, and the supernatant after immunoprecipitation with L23 contained L61-reactive IL-2/IL-2R complex, whereas L15 immunoprecipitated almost all the complex. Limited digestion of IL-2-cross-linked Y479 cells with trypsin caused the liberation of 45 kDa IL-2R fragment cross-linked with IL-2. This complex was immunoprecipitated by L15 or L61 but not by L23. These results suggest that there are at least two distinct 70 kDa IL-2R on the surface of Y479 cells.
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PMID:Two distinct P70 interleukin-2 receptors on a murine large granular lymphocyte clone Y479. 179 Oct 35

Significant proliferative responses of peripheral blood mononuclear cells (PBMC) to crude Plasmodium falciparum schizont antigen (M.Ag) or purified recombinant 31.1 Ag (part of gp 195) were observed only in 46 and 39%, respectively, of 50 healthy subjects 5 to 63 years old living in Gabon, a malaria-endemic area. High responses to pokeweed mitogen were observed in all the subjects except one. Interferon-gamma (IFN-gamma) production paralleled the proliferative response, but in some subjects proliferation without a IFN-gamma response was observed. The proportion of subjects responding to M.Ag and 31.1 Ag increased with age. By cytofluorometric analysis performed with PBMC from 27 subjects, a substantial proportion of CD3+ T cells was found to bear the activation marker HLA-DR. However, the CD3+ cells expressed very low levels of CD25 (p55 chain of IL-2 receptor). The expression of CD25 on T cells and their capacity to respond to M.Ag were significantly correlated. In four subjects an increase in the percentage of CD3+ cells bearing the very late activation marker VLA-1 was observed.
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PMID:In vivo decreased expression of CD25 (p55 chain of IL-2 receptor) on CD3+ T cells correlates with low in vitro responsiveness to Plasmodium falciparum antigen in subjects living in a malaria endemic area. 182 93

The interaction of interleukin 2 with specific cellular receptors plays an essential role in the allostimulated proliferation and differentiation of T cells. Recent chemical linking studies have demonstrated that the human high-affinity IL-2 receptor is a membrane complex composed of at least two distinct subunits, which are the p55 (alpha-chain) and p75 (beta-chain) subunits. The IL-2R beta chain is supposed to play a role in the signal transduction of IL-2, but the exact mechanism is still unknown. In this study, we investigated the effects of a newly established anti-IL-2R beta chain monoclonal antibody (MoAb, TU-27) on the induction of cytotoxic T lymphocytes (CTLs) using the cell-mediated lympholysis (CML) assay. TU-27 in combination with H-31, a MoAb directed against the IL-2R alpha chain, produced inhibition of cytotoxicity, while TU-27 alone could not inhibit cytotoxicity, while TU-27 alone could not inhibit cytotoxicity at any concentration. TU-27 plus H-31 prevented the expansion of CD4+ cells and CD8++ cells in mixed lymphocyte culture (MLC). Furthermore, we examined the serial changes in the expression of the IL-2R beta chain on peripheral blood lymphocytes from renal transplant recipients using two-color immunofluorescence flow cytometry, so as to investigate correlations between IL-2R beta chain expression and the occurrence of allograft rejection. Here, we report that the IL-2R beta chain is expressed on CD4-positive (CD4+) cells and strongly CD8-positive (CD8(+)+) cells in association with acute rejection, indicating that IL-2R beta chain expression appears to increase on alloreactive T cells.
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PMID:Expression of the interleukin 2 receptor beta chain (p75) in renal transplantation--applicability of anti-interleukin-2 receptor beta chain monoclonal antibody. 183 4

The in vitro immunosuppressive properties of a novel, marine-derived compound, discodermolide, are reported here. Discodermolide suppressed the proliferative responses of splenocytes in the murine two-way mixed lymphocyte reaction (MLR) and concanavalin A stimulated cultures, with IC50 values of 0.24 microM and 0.19 microM, respectively. There was no evidence of cytotoxicity for murine splenocytes at concentrations of discodermolide as high as 1.26 microM. Similarly, discodermolide suppressed the proliferative responses of human peripheral blood leukocytes (PBL) in the two-way MLR, and Con A and phytohemagglutinin mitogenesis. The IC50 values were 5.65 microM, 28.02 microM, and 30.12 microM for the MLR, Con A, and PHA mitogenic responses, respectively. There was no evidence of cytotoxicity toward human PBL at discodermolide concentrations as high as 80.64 microM. Discodermolide was equally effective, compared with cyclosporine, in suppressing the PMA-ionomycin induced proliferation of purified, murine T cells, with IC50 values of 9.0 nM and 14.0 nM for discodermolide and CsA, respectively. The production of IL-2 by PMA-ionomycin stimulated T cells was not inhibited by discodermolide; however, the percentage of IL-2 receptor-bearing cells as measured by immunofluorescence with 7D4 antibody, specific for the 55-kDa chain (p55) comprising the murine IL-2 receptor, was reduced. The expression of a similar chain comprising the human IL-2 receptor (Tac antigen, p55) by PHA or Con-A-stimulated PBL was similarly suppressed by discodermolide. The precise mechanism of action of discodermolide remains to be elucidated.
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PMID:Discodermolide--a new, marine-derived immunosuppressive compound. I. In vitro studies. 183 64

The role of activated T cells in the mediation of antitumor responses has been documented in several experimental models. In some of these, interleukin-2 (IL-2) has been used as a means to induce and expand the antitumor effects of the T cells. IL-2 has been tested in clinical trials for cancer treatment. Surprisingly, T cells appear to be inactivated by IL-2 in these clinical trials. T cells obtained from peripheral blood after IL-2 therapy showed decreased responses to mitogens and alloantigens, did not proliferate in vitro in response to IL-2, and did not mediate non-major histocompatibility complex-restricted cytotoxicity or targeted lysis in the presence of bispecific monoclonal antibodies. In this study, we present evidence that these post-IL-2 therapy T cells are not irreversibly inactivated; they can be activated in vitro by anti-CD3 monoclonal antibody together with IL-2 to upregulate the p55 component of the IL-2 receptor and proliferate. Nevertheless, following activation by anti-CD3 and IL-2, the level of targeted T-cell cytotoxicity mediated by the post-IL-2 therapy T cells was significantly lower than that by pre-IL-2 therapy T cells. Although in vivo treatment with IL-2 alone induces natural killer (NK) cells to mediate lymphokine-activated killer activity, these data suggest that the T-cell lytic function is inhibited by this treatment and only partially reversible by subsequent T-cell receptor activation using anti-CD3 mAb. Exposure of T cells to anti-CD3 mAb prior to in vivo IL-2 treatment generates T-cell lytic activity in vitro. These results, together with preclinical murine studies, suggest that a combined in vivo protocol of anti-CD3 mAb and IL-2, starting first with the anti-CD3 mAb, may cause activation of the T cells in addition to the activation of NK cells and thus warrant clinical testing.
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PMID:Activation of human T cells obtained pre- and post-interleukin-2 (IL-2) therapy by anti-CD3 monoclonal antibody plus IL-2: implications for combined in vivo treatment. 183 66

Patient entry is now complete in a prospective trial of anti-Tac, a murine IgG2a monoclonal antibody directed against the p55 chain of the human IL-2 receptor, for the prevention of renal allograft rejection. Recipients of primary cadaver allografts were randomized to receive either anti-Tac (20 mg q.d. x 10 days beginning POD 1) plus low-dose CsA (4 mg/kg/day), azathioprine (2 mg/kg/day), and prednisone (30 mg q.d.), or conventional triple therapy with CsA (8 mg/kg/day), azathioprine, and prednisone. Forty patients were entered in each group, with current followup from 6 to 26 months. The results show a significant reduction in early rejection episodes in the anti-Tac-treated patients. During the 10-day treatment, 5 of 40 anti-Tac patients had rejection episodes, compared with 21 of 40 control patients (P less than 0.001). Anti-Tac significantly delayed the time to the first rejection (12.5 +/- 6.3 vs. 7.6 +/- 6.7 days) (P less than 0.05). Despite these effects, there were no differences in either actual or actuarial graft or patient survival between the two groups. Pneumonia, primarily CMV, developed in 5 treated and 4 control patients. In patients with functioning grafts mean serum creatinine at 3 months was 1.8 +/- 0.7 in the anti-Tac group and 2.0 +/- 0.8 in the control group (P = NS); at 12 months the values were 2.3 +/- 1.5 and 1.8 +/- 0.5, respectively (P = NS). The peak expression of IL-2 receptors on circulating T-cells was significantly lower in anti-Tac patients (15.1 +/- 3.6%) than in controls (21.9 +/- 4.5%) (P less than 0.05). Seven of 10 patients tested to date developed antimouse immunoglobulin antibodies, with antiidiotype shown in 6. These antibodies do not preclude subsequent treatment with OKT3. Five patients in this and previous anti-Tac protocols have received OKT3 for acute rejection despite known pretreatment antimouse antibodies, with resolution of rejection in all cases.
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PMID:A randomized prospective trial of anti-Tac monoclonal antibody in human renal transplantation. 184 50

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