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

We report a new, monocyte-independent system for the induction of activation and proliferation of human T cells in response to murine hybridomas expressing the OKT3 monoclonal antibody (OKT3 hybridomas). Incubation of nylon-wool-nonadherent (NA) lymphocytes or purified T cells with OKT3 hybridomas resulted in interleukin-2 (IL-2) production, expression of IL-2 receptor, modulation of the CD3 antigen, and proliferation. In contrast, murine hybridomas (OKT4, OKT8, anti-HLA-DR, and others) expressing monoclonal antibodies (mAb) other than OKT3 did not induce T-cell activation and proliferation. T cells did not respond to OKT3 mAb alone. OKT3 hybridomas alone did not produce interleukin-1 (IL-1) or other soluble factors that might be involved in the induction of IL-2 production by T cells, and they did not contain membrane-bound IL-1. In addition, IL-1 activity was not detected in cultures of NA-lymphocytes and OKT3 hybridomas, clearly demonstrating that IL-1 was not required, at least in this system, for T-cell activation and proliferation. Direct cell-cell contact between T cells and OKT3 hybridomas was required for IL-2 production. Thirty to fifty percent of T cells formed conjugates with the OKT3 hybridomas but not with the OKT4 or OKT8 hybridomas. Both conjugate formation and IL-2 production were significantly inhibited by the OKT3 mAb and by the anti-LFA-1 mAb. The cells responsible for IL-2 production were found to be of the T3+ T4+ T8- Leu 7- Leu 11- phenotype. IL-2 activity produced by NA-lymphocytes in response to OKT3 hybridomas became detectable as early as 1 hr and reached a maximum by 8 hr, preceding IL-2 receptor expression, modulation of the CD3 antigen, and [3H]thymidine incorporation of T cells. T cells produced higher concentrations of IL-2 in response to OKT3 hybridomas than in response to equal numbers of monocytes and OKT3 mAb. Addition of monocytes to cultures of T cells and OKT3 hybridomas resulted in suppression of IL-2 production in a concentration-dependent manner, suggesting that monocytes regulate the levels of IL-2 production. This monocyte-independent system may be useful for further dissection of T-cell activation and proliferation and its regulation by monocytes.
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PMID:Monocyte-independent interleukin-2 production and proliferation of human T cells in response to murine hybridomas expressing the OKT3 monoclonal antibody: interleukin-1 is not required for T-cell proliferation. 296 76

To investigate the possible involvement of some cell surface structures on lymphoid cells in the functional activity of lymphokine activated killer (LAK) cells, a number of monoclonal antibodies (Mab) against such structures was studied for their ability to inhibit LAK activity in a standard cytotoxicity assay against the natural killer-insensitive target cell EL-4. Almost complete inhibition of LAK activity resulted from incubation with antibodies to the LFA-1 antigen, while blocking of the Lyt 2 antigen reduced cytotoxic activity about 50%. Mab to T-200 gave a weak and inconsistent inhibitory activity, while antibodies to Thy 1, L3T4, IL-2 receptor and MHC class I antigens were without effect. Mab to LFA-1 and Lyt 2 inhibited LAK activity towards EL-4, YAC-1 and differentiated F-9 teratocarcinoma cells, but did not affect LAK-mediated killing of undifferentiated F-9 cells. Experiments with separate preincubation of effector and target cells revealed that both LFA-1 and Lyt 2 inhibited LAK activity at the effector cell level only.
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PMID:Functionally involved cell surface antigens on murine lymphokine activated killer cells. 329 81

Acute P. falciparum malaria is associated with a loss of antigen-responsiveness of peripheral T cells, depletion of T cells characterized by high surface expression of the adhesion molecule LFA-1, and increased plasma levels of the T-cell activation marker soluble IL-2 receptor (sIL-2R). In the present study we show that clinical episodes of P. falciparum malaria produced an increase in plasma levels of soluble ICAM-1 (sICAM-1) and ELAM-1 (sELAM-1). The increase was transient and subsided slowly (sICAM-1) or rapidly (sELAM-1) following drug cure. The increases in plasma sICAM-1 and sELAM-1 were significantly correlated, and were furthermore associated with a concomitant increase in plasma levels of sIL-2R. Finally, plasma levels of sICAM-1, but not sELAM-1, were inversely correlated to the fraction of peripheral T cells having high surface expression of LFA-1, the receptor for T-cell adhesion to ICAM-1. Taken together, these observations suggest that acute P. falciparum malaria is characterized by a state of endothelial inflammation associated with the adherence of activated T cells.
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PMID:Increased plasma levels of soluble ICAM-1 and ELAM-1 (E-selectin) during acute Plasmodium falciparum malaria. 768 46

Two major populations of extrathymically differentiated T cells exist in the liver and intestine. Such T cells in the liver have TCR of intermediate intensity (i.e., intermediate TCR cells) and constitutively express IL-2 receptor beta-chain (IL-2R beta), whereas those in the intestine, especially intraepithelial lymphocytes, have TCR of bright intensity, consisting of a mixture of IL-2R beta+ and IL-2R beta-. All mature thymocytes and thymus-derived T cells seen in the peripheral immune organs are TCR-bright+ IL-2R beta- under resting conditions. When the expression pattern of adhesion molecules, including CD44, L-selectin, LFA-1 and ICAM-1, was compared among these T-cell populations, they displayed quite unique patterns of expression. All extrathymic T cells in the liver, intestine, and even other organs were CD44+ L-selectin-LFA-1++ICAM-1+, whereas thymocytes and thymus-derived T cells were CD44-L-selectin+LFA-1+ICAM-1-. This inverted expression of adhesion molecules between extrathymic T cells and thymus-derived T cells might be associated with their unique tissue-localization.
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PMID:A similar expression pattern of adhesion molecules between intermediate TCR cells in the liver and intraepithelial lymphocytes in the intestine. 779 43

32 monoclonal antibodies reactive with human CD antigens were tested against tamarin peripheral blood lymphocytes, ConA blasts and lymphoblastoid B cell lines derived from tamarin cells. Reagents that cross-react with MHC class I and II, B cells (CD20, -21 and -23), monocytes (CD14) and NK cells (CD16, -56) have been identified. In addition monoclonals that cross-react with T cells (CD2, CD3), the CD4/CD8 subsets of T cells and the IL-2 receptor (CD25) are reported. A monoclonal against the beta chain of LFA-1 (CD18) cross-reacted strongly, but there was only a very poor cross-reaction with a monoclonal against the alpha chain of CD11a. Two monoclonals tested against ICAM-1(CD54) were negative.
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PMID:Selection of monoclonal antibodies for the identification of lymphocyte surface antigens in the New World primate Saguinus oedipus oedipus (cotton top tamarin). 783 81

We investigated how NK cells, extrathymic T cells, and thymus-derived T cells are activated in mice during infection with an intracellular pathogen, Listeria (L.) monocytogenes. Although macrophages and granulocytes are known to be involved in the elimination of this pathogen in an early phase of infection, it was still controversial what type of lymphocytes are induced as effectors in subsequent phases. When mice were ip injected with 1 x 10(3) L. monocytogenes (a sublethal dose), a prominent increase in the number of mononuclear cells in the liver and spleen was induced. Phenotypic analysis revealed that serial induction of lymphocyte subsets, NK cells-->extrathymic T cells-->thymus-derived T cells, occurred in these organs. Extrathymic T cells were estimated to have intermediate CD3 and a high level of IL-2 receptor beta-chain on the surface (i.e., intermediate CD3 cells). These mice became free from infection after 2 weeks. In the case of oral administration, 1 x 10(3) L. monocytogenes increased the number of cells in the liver and the number of intraepithelial and lamina propria lymphocytes in the intestine. Phenotypic analysis also showed a sequential induction of lymphocyte subsets in the liver and the induction of extrathymic T cells in the intestine. Preelimination of intermediate TCR cells and NK cells by in vivo treatment with anti-LFA-1 mAb made mice susceptible to an ip injected sublethal dose of L. monocytogenes. These results reveal a unique order of lymphocyte induction during listerial infection and indicate that extrathymic T cells might be one of the important cells in achieving resistance against L. monocytogenes.
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PMID:Unique order of the lymphocyte subset induction in the liver and intestine of mice during Listeria monocytogenes infection. 786 76

The biological significance of the signals triggered by the interaction of cell surface expressed LFA-1 and ICAM-1 has been investigated in Con A and immobilized anti-CD3 mAb stimulated cultures. When added at the beginning of activation in the presence of Con A, soluble anti-LFA-1 and anti-ICAM-1 mAbs could strongly inhibit cell proliferation. Such inhibitory effect was also exhibited in the proliferative response of thymocytes to immobilized anti-CD 3 mAb activation. However, the soluble anti-LFA-1 mAb was unable to inhibit the proliferation of primed thymocytes preactivated with Con A for 24 h or of IL-1 + IL-2 activated fresh thymocytes. Anti-LFA-1 mAb could profoundly inhibit Con A-induced thymocytes to produce IL-2 and IL-6 and to reduce IL-2 receptor expression. By contrast, anti-LFA-immobilized on plastic plates together with immobilized anti-CD 3 mAbs or CD 3 cross-linking with LFA-1 by secondary antibodies resulted in an enhanced activation signals for thymocytes to proliferate compared with that activated by anti-CD 3 alone. Thus, mAb to LFA-1 is a functional molecule for thymocyte activation, mediating signals contributed to very early phases of signal transduction through TCR/CD 3 pathway, and that LFA-1 might provide a costimulatory signal for expression of IL-2 R and IL-2 production.
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PMID:[Functional roles of LFA-1 involved in signal transduction for thymocyte activation]. 787 72

Major adhesion routes between lymphoid cells involve the receptor/ligand pairs LFA-1/ICAM-1 and CD2/LFA-3, in addition to VLA or CD44 molecules. In this study we evaluated the role of these adhesion receptors in the proliferative response of lymphoid cells to interleukin-2 (IL-2). Blocking studies were performed with a panel of monoclonal antibodies (mAb) directed against these adhesion molecules. Selective inhibition of recombinant (r)IL-2-induced cell proliferation was observed with mAb directed against the alpha or beta subunit of LFA-1 or to its ligand ICAM-1. Interestingly, rIL-2-induced proliferation was also inhibited by NKI-L16, and anti-1 alpha antibody known to enhance cell-cell interaction. Resting lymphocytes were preferentially susceptible to the inhibition, particularly in an early phase of culture and when stimulated with a relatively low dose of rIL-2. By using mAb that specifically could block distinct rIL-2 activation pathways, LFA-1/ICAM-1 interaction was found to be required for p55 IL-2 receptor (IL-2R)-mediated interaction of rIL-2 with its high-affinity receptor, but not for p75 IL-2R-mediated responses. Furthermore, it was shown that the rIL-2 response of T lymphocytes, but not of natural killer cells, was dependent on LFA-1/ICAM-1 interaction. This suggests that LFA-1/ICAM-1 interaction is required for an optimal rIL-2 response of cells capable of IL-2 secretion. Our data provide evidence for the hypothesis that adhesion receptor-directed release of IL-2 may result in a locally high concentration of IL-2 that triggers high-affinity IL-2R signaling and up-regulates p55 IL-2R to enhance cytokine responsiveness.
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PMID:Role of LFA-1/ICAM-1 in interleukin-2-stimulated lymphocyte proliferation. 790 74

All circulating T cells constitutively express the adhesion molecule leukocyte function-associated antigen 1 (LFA-1; CD11a/CD18) at either low or high surface density. In the present paper we have compared the expression of the LFA-1 alpha-chain CD11a on peripheral T cells obtained from indigenous Africans with permanent residence in Africa to T cells from indigenous Danes with permanent residence in Denmark. The Africans had a higher percentage of T cells with high CD11a expression than did Danish donors. The difference was evident in both the CD3-, CD4+, and CD8+ subsets. The difference did not appear to reflect a higher degree of peripheral T-cell activation in the African donors, as T-cell expression of the activation marker IL-2 receptor (CD25) was similar in the two groups. Furthermore, we observed no apparent correlation between CD3+ CD11a(hi) and CD3+ CD25+ values in individual donors. LFA-1 expression on T cells obtained from expatriate Africans with long-term residence in Denmark resembled that of Danish permanent residents more than that of Africans with permanent residence in Africa. In addition, T cells obtained from two expatriate Danes with long-term residence in rural Africa were phenotypically similar to those from African permanent residents. The data suggest that the observed difference is environmental rather than ethnic and may reflect the degree of exposure to infectious agents.
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PMID:Differential T-cell expression of LFA-1 in residents from Africa and Denmark. Description of the phenomenon and its possible basis. 791 22

Increased serum IgE and enhanced susceptibility to viral infections, decreased levels of interferons, lymphocytic skin infiltrates and IgE-bearing epidermal Langerhans cells are striking features in patients with atopic eczema (AE). Since the hyper-IgE syndrome is known to improve under alpha-interferon (alpha-IFN) therapy, we treated 7 patients with severe AE and high serum IgE exclusively with 3 x 10(6) units IFN alpha 2b thrice weekly for 3 months. Before treatment the skin infiltrates mainly consisted of CD3+/CD4+/TcR alpha/beta + lymphocytes, whereas the CD3+/CD8+ phenotype was limited to about 10% of cells. After 6 weeks of therapy, epidermal inflammation with CD4+ and CD8+ cells was reduced but dense infiltrates remained in papillary perivascular areas. Expression of TcR gamma/delta, HLA-DR and CD25 showed no significant changes. Initially high serum IgE and soluble CD23 as well as cell-bound IgE dropped under therapy, whereas a short-term elevation in serum IL-2 receptor was observed. On peripheral blood lymphocytes slightly reduced expression of HLA-DR, LFA-1, CD23 and ICAM-1 was seen after 100 days. LFA-3 expression became reduced in 4 patients, the CD4/CD8 ratio decreased in all cases. After an initial therapeutic response of all patients, significant longer-lasting improvement of the skin lesions could only be observed in 2 of 7 patients. The data of our long-term study suggest that systemic IFN alpha 2b treatment leads to a remarkable reduction in epidermal inflammation but does not significantly influence cutaneous cell subsets. Immunomodulatory effects became obvious by reduced peripheral cell subsets expressing TcR alpha/beta, MHC class II and adhesion molecules.
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PMID:Effects of interferon-alpha-2b on the clinical course, inflammatory skin infiltrates and peripheral blood lymphocytes in patients with severe atopic eczema. 849 70


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