Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P14784 (IL-2 receptor)
 3,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment with combined IL-2 and alpha-IFN has resulted in synergistic antitumour efficacy in animal studies. The mechanisms responsible for this synergy remain unclear. In this study, several immune parameters which might be involved in mediating antitumour activity have been monitored serially in 15 patients with advanced malignant melanoma or renal cell cancer during treatment with concurrent IL-2 and alpha-IFN. Both drugs were given subcutaneously in low to moderate (outpatient) dosages but for a prolonged duration. This treatment resulted in remarkable immunomodulation. In vivo induction of cytotoxicity against K562 and Daudi target cells was consistently seen, and percentages of peripheral blood cells expressing CD 25 (IL-2 receptor) and CD 56 (Leu-19) increased. In vitro proliferation of lymphocytes in response to IL-2 was enhanced during the treatment periods, whereas spontaneous proliferation was inhibited. Moreover, correlations between immune parameters and subsequent clinical responses were present in the early phase of the study. Cytotoxicity levels generated in vivo as well as the percentage of CD 56+ lymphocytes were higher in patients who responded to treatment than in non-responders. In contrast, responders had lower levels of CD 25+ cells. These findings indicate that it might be possible to select patients who are likely to benefit from prolonged immunotherapy.
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PMID:Immunomodulation during prolonged treatment with combined interleukin-2 and interferon-alpha in patients with advanced malignancy. 767 79

Human interleukin-2 (IL-2) alpha helix B is more conserved than the whole molecule, but has been less studied than other alpha helices of IL-2. Using site-directed mutagenesis, several IL-2 mutants in this helix were obtained. We found that the IL-2 mutant containing Leu at position 62 (Leu62-IL-2) loses its ability to bind IL-2 receptor subunit alpha (IL-2R alpha), but retains binding affinity to IL-2R subunit beta gamma as well as some bioactivity; nevertheless, another substitution at the same residue, Arg62IL-2, loses its binding ability to both IL-2R alpha and IL-2R beta gamma, and can no longer stimulate IL-2-dependent cell growth, showing that Glu62 not only takes part in IL-2R alpha binding, but can also affect IL-2 binding to IL-2R beta gamma. In this regard, Glu62 may be a key site in the IL-2/IL-2R alpha interaction, and can facilitate IL-2R ternary-complex formation, leading to IL-2R alpha-mediated, IL-2-stimulated signal transduction.
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PMID:Substitutions at the Glu62 residue of human interleukin-2 differentially affect its binding to the alpha chain and the beta gamma complex of the interleukin-2 receptor. 777 25

Immunohistochemical and immunoserological evidence supports the involvement of both cell-mediated and humoral mechanisms in the pathogenesis of melanocyte destruction in vitiligo. Punch biopsies from depigmented vitiliginous skin (VS), normal-looking pigmented skin (PS), and marginal skin (MS) from patients with generalized vitiligo (n = 15) were labeled with K 1.2.58, OKM1 (CD11b), Leu 11b (CD16), Leu 19 (CD56), IFN-gamma receptor, IL-2 receptor (CD25), IgG, IgM, C3c, and C3d MoAbs. In addition, in vitro effects of vitiligo sera (n = 13) on human newborn melanocytes (HMel) under different culture conditions were studied. The immunohistochemical findings showed absence of K 1.2.58+ epidermal melanocytes in VS and abnormal morphology in MS. In these areas, a few CD11b+ cells in the dermis and epidermis could be detected but no significant numbers of CD16+ or CD56+ cells were seen among the mononuclear cellular infiltrate. IL-2 and IFN-gamma receptors were clearly expressed by the cellular infiltrate. No significant deposition of complement or immunoglobulin was seen. The addition of vitiligo sera to HMel cultures induced a significant cellular proliferation. The stimulation of cell proliferation occurred regardless whether the sera were added alone or when preheated (56 degrees C for 1 hr) and then supplemented with a complement source (P < 0.01 at 2%, P < 0.001 at 10%, and P < 0.01 at 20% for sera alone) (P > 0.05 at 2%, P < 0.05 at 10%, and P < 0.01 at 20% for decomplemented sera plus complement).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Further evidence for involvement of both cell mediated and humoral immunity in generalized vitiligo. 807 43

Interleukin-2 (IL-2) is a 133 amino acid alpha-helical protein secreted by activated T-cells. Combinatorial cassette mutagenesis was used to investigate the functional role of a continuous five amino acid region of IL-2 suspected to interact with the intermediate-affinity IL-2 receptor. A limited random library of IL-2 mutants was constructed in which residues 17-21 (Leu-Leu-Leu-Asp-Leu) were simultaneously mutated. The proteins were produced in an Escherichia coli expression system and screened in a biological assay for their ability to mediate the proliferation of a murine IL-2-dependent cell line. From the over 2600 clones examined, only 42 exhibited significant activity, confirming the functional importance of this region. Selected clones were purified and further characterized by biological and receptor binding assays. Viewed in the context of the recently revised 2.5-A crystal structure for IL-2, these results suggest the following conclusions: both Asp20 and Leu21, as shown by their sensitivity to mutation, are the functionally more important residues in this region, but for different reasons. Asp20 is solvent-accessible and likely plays a direct receptor contact role as previous studies have indicated. Leu21, in contrast, is completely buried in the hydrophobic core of the protein. Substitutions at this position, even a conservative Leu-->Val substitution, were found to perturb the precise hydrophobic packing arrangements that are critical for activity, resulting in a significant loss of function. In addition, one of the analogs identified in the screen was found to be 2-3 times more potent than the wild-type protein.
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PMID:Mutagenic analysis of a receptor contact site on interleukin-2: preparation of an IL-2 analog with increased potency. 820 93

Cassette and deletion mutagenesis were used to analyze the function of the amphipathic alpha-helices in the transmembrane domain of DAB389-interleukin-2 (IL-2), a fusion protein which is targeted to the interleukin-2 receptor. We demonstrate that the in-frame deletion of 60 amino acids, from Asn204 to Glu263 in DAB389-IL-2, results in complete loss of cytotoxic activity, whereas when the amphipathic regions from Asp208 to Ser220 and Ala244 to His258 are replaced with idealized amphipathic helices composed of repeating Glu, Lys, and Leu residues, the mutant fusion toxin has low but detectable activity. DAB389-IL-2 and both variants form channels in artificial phospholipid bilayers with conductances identical to those formed by diphtheria toxin. Both mutant fusion toxins bind to the high affinity IL-2 receptor with affinities similar to that of DAB389-IL-2. The fact that these mutants have markedly reduced or absent cytotoxic activity, but possess "wild type" catalytic activity, binding affinities, and channel conductances, suggests the existence of a step in the intoxication pathway, defective in the mutants, which occurs after DAB389-IL-2 binds to the IL-2 receptor. It is unknown whether this step occurs prior or subsequent to channel formation, but it is essential for the efficient delivery of the ADP-ribosyltransferase from DAB389-IL-2 to the cytosol of target cells.
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PMID:Structure/function analysis of the transmembrane domain of DAB389-interleukin-2, an interleukin-2 receptor-targeted fusion toxin. The amphipathic helical region of the transmembrane domain is essential for the efficient delivery of the catalytic domain to the cytosol of target cells. 850 30

The heterodimer-forming leucine zippers Fos and Jun can efficiently mediate the formation of bispecific F(ab')2 when they are fused separately to two different Fab' fragments. This recombinant method can be used in conjunction with the humanization process to yield humanized bispecific F(ab')2. The potential immunogenicity of the leucine zippers can be eliminated by their removal using pepsin digestion. This method has been scaled up to produce hundreds of milligrams of a bispecific F(ab')2 that targets two subunits of the human IL-2 receptor.
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PMID:Preparation of a bispecific F(ab')2 targeted to the human IL-2 receptor. 858 74

The aim of this study was to quantify and characterize the CD4+ and CD8+, CD45RA+, CD45RO- T-lymphocytes that paradoxically expressed the CD29 bright+ phenotype in health and in rheumatoid arthritis. We further evaluated their clinical implications. Blood samples were obtained from 100 patients with rheumatoid arthritis and 40 age- and sex-matched controls. Cell surface antigens and interleukin-2 (IL-2) binding were detected on CD4+ and CD8+ peripheral blood T-lymphocytes (T-PBL) by three-colour flow cytometry. One-third of the patients were clinically evaluated at the time of blood sampling. In healthy donors, we found 16 +/- 14% of CD29 bright+ cells among CD4+, CD45RA+, RO- T-PBL. These "false naive" CD4+ T-PBL were Leu-8+, and a majority expressed the CD25/p55 receptor (IL-2R alpha chain), while a minority showed the CD11a bright+, CD69+ and/or CD122/p75+ (IL-2R beta chain) phenotype, and few cells were CD31 bright+ and HLA-DR+. In rheumatoid arthritis, their proportion among CD4+, CD45RA+, RO- cells increased to 25 +/- 15% (P < 0.001, compared with controls). In patients, the reductions in CD31 and CD38 expression (P < 0.05 for both), as well as the enhanced CD25 expression (P < 0.001) on CD4+, CD45RA+, RO- T-PBL reflected a more differentiated phenotype. The occurrences of CD25 and CD122 were increased on false naive CD4+ T-PBL (0.01 < P < 0.001); however, the binding of IL-2 remained very low (in contrast to the binding of IL-2 on CD45RO+ T-PBL). Furthermore, a major subset of CD8+, CD45RA+, RO- T-PBL (45 +/- 17% in controls) expressed the CD29 bright+ phenotype. These "false naive" CD8+ T-PBL included a great many of CD11b+, CD28- cells, while a minority showed the HLA-DR+, CD69+ and/or CD122+ phenotypes. Patients with low levels of IgM rheumatoid factors (IgM-RF; but with active disease) had an elevated proportion of CD45RA+, RO- cells among the CD8+ T-PBL, in part due to an increased proportion of false naive cells (P < 0.05). In patients, the false naive CD8+ T-PBL showed down-regulated CD11b and an increased expression of IL-2 receptor chains (CD25 and CD122; 0.05 < P < 0.01), but without a significant increase in IL-2 binding. More CD69 on false naive CD8+ T-PBL was found in patients with high levels of IgM-RF (P < 0.005 compared to patients with low IgM-RF). Finally, both false naive CD4+ and CD8+ T-PBL correlated with the clinical process and outcome variables (0.05 < P < 0.01). The levels of activated false naive (CD4+ T-PBL (CD25+ and/or CD122+) or CD8+ T-PBL (CD69+ and/or CD122+) were associated with clinical parameters of disease activity (0.05 < P < 0.01). Thus, in rheumatoid arthritis, false naive T-PBL showed important qualitative differences. The levels of activated false naive T-PBL could be particularly interesting for monitoring disease evolution.
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PMID:Flow cytometric characterisation of the "false naive" (CD45RA+, CD45RO-, CD29 bright+) peripheral blood T-lymphocytes in health and in rheumatoid arthritis. 885 29

Immunocytochemical analyses of human plaques and experimental arterial lesions have implicated activated lymphocytes and monocytes in the pathogenesis of atherosclerosis, as demonstrated by the expression of interleukin-2 (IL-2) membrane receptors and major histocompatibility complex class II epitopes. The objective is to determine if targeting these cells with an IL-2 receptor-specific chimeric toxin, DAB486-IL-2, can inhibit experimental post-angioplasty vascular neointimal thickening. Twenty-two atherogenically modeled rabbits were treated in vivo with DAB486-IL-2 (0.1 mg/kg per day i.v.; n = 11) or placebo (n = 11) for 10 days following aortic balloon angioplasty (4 atm x 30 s each x 2 dilatations). In vitro 3H-leucine incorporation studies of mononuclear leukocyte and vascular smooth muscle cell protein synthesis inhibition by DAB486-IL-2 were also performed. Angioplasty sites were examined for evidence of hyperproliferative atherosclerotic narrowing by quantitative angiography and histomorphometry of neointimal cross-sectional area at baseline and 6 weeks after injury. In vitro Concanavalin-A stimulated rabbit mononuclear leukocyte protein synthesis was 50% inhibited by DAB486-IL-2 at a concentration (IC50) of 6 x 10(-11) M. Rabbit vascular smooth muscle cells were approximately 150-fold less sensitive to DAB486-IL-2 (IC50 = 10(-8) M). In vivo studies showed no change in angioplasty site angiographic minimum luminal diameter at 6 weeks in DAB486-IL-2 treated animals (from 2.96 +/- 0.52 to 2.96 +/- 0.48 mm; percent cross-sectional area reduction = 1 +/- 10%; P = N.S.). In control animals, luminal diameter decreased from 2.79 +/- 0.4 to 2.32 +/- 0.52 mm at 6 weeks, and percent cross-sectional area was reduced by 34 +/- 14% (P < 0.01 vs. placebo). Quantitative histomorphometric angioplasty segmental intimal cross-sectional area reduction of treated and placebo vessels also differed significantly (19 +/- 16% vs. 31 +/- 21%; P < 0.05). DAB486-IL-2 caused no adverse effects on animal survival, weight or hepatic transaminase levels. We conclude that post-angioplasty administration of the chimeric toxin DAB486-IL-2 inhibits angiographic narrowing and neointimal thickening in the atherogenic rabbit model. Although this IL-2 receptor-specific molecule was cytotoxic in vitro for activated mononuclear leukocytes and vascular smooth muscle cells, systemic toxicity did not occur in vivo at a dose comparable to that evaluated in clinical trials of this agent. Potential anti-proliferative effects of this chimeric toxin may be mediated by direct local inhibition of leukocyte-mediated inflammation, or through the indirect modification of vascular cell mitogenesis and cytokine release.
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PMID:Interleukin-2 receptor-specific fusion toxin inhibits barotrauma-induced arterial atherosclerosis. 887 29

Interleukin 2 (IL-2) interacts with a receptor (IL-2R) composed of three subunits (IL-2R alpha, IL-2R beta and IL-2R gamma). IL-2R beta plays a critical role in signal transduction. An anti-human IL-2 mAb (H2-8) produced after immunization with peptide 1-30 of IL-2 was found to recognize the region occupied by Asp20, at the exposed interface between alpha-helices A and C. Muteins at position 17 and 20 are not recognized by mAb H2-8. mAb H2-8 specifically inhibits the IL-2 proliferation of TS1beta cells which are dependent on the expression of human IL-2R beta chain for IL-2 proliferation. Substitution at internal position Leu17 demonstrates that this position is essential for IL-2 binding and IL-2 bioactivity. New IL-2 mutants at position Asp20 have been analysed. Substitutions Asp --> Asn, Asp --> Lys, Asp --> Leu, show a correlation between diminished affinity for IL-2 receptor and reduced bioactivity measured on TS1beta cells. Mutein Asp Arg lose affinity for IL-2R and bioactivity simultaneously. Furthermore, during the course of the study we have found that mutein Asp20 --> Leu is an IL-2 antagonist. The biological effects of mAb H2-8 and the properties of new mutants at positions 17 and 20 demonstrate that this region of alpha helix-A is involved in IL-2-IL-2R beta interactions.
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PMID:Analysis of human IL-2/IL-2 receptor beta chain interactions: monoclonal antibody H2-8 and new IL-2 mutants define the critical role of alpha helix-A of IL-2. 923 11

Activated mucosal T lymphocytes correlate with the intestinal inflammation of inflammatory bowel disease. Activated T cells elaborate interferon-gamma (IFN-gamma) and express high-affinity interleukin-2 (IL-2) receptors. The IL-2/diphtheria toxin fusion protein (DAB389IL-2) has been shown to specifically kill high affinity IL-2 receptor-bearing cells. We tested whether DAB389IL-2 could specifically target activated lamina propria lymphocytes. Lymphocytes were activated in vitro with phytohemagglutinin and IL-2 for 24-48 hr. Toxin efficacy was determined by the [14C]leucine incorporation, IFN-gamma ELISA, and flow cytometry. DAB389IL-2 (10(-11) M) inhibited protein synthesis by 80% in activated lamina propria lymphocytes. This inhibition was blocked by coculture of either excess IL-2 or a nonfunctional IL-2 diphtheria toxin mutant protein. DAB389IL-2 (10(-12) M) also significantly reduced the numbers of activated helper T cells and IFN-gamma levels in 24-hr cultures. DAB389IL-2 specifically targets activated IL-2 receptor-positive lamina propria lymphocytes and is a potential new therapeutic agent for patients with active inflammatory bowel disease.
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PMID:Interleukin-2 fusion protein (DAB389IL-2) selectively targets activated human peripheral blood and lamina propria lymphocytes. 924 61


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