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M Tsudo

Publications and source records attributed to M Tsudo.

At least 55 records · Page 3Linked to original sources
PubMed1989

Reconstitution of a functional IL-2 receptor by the beta-chain cDNA. A newly acquired receptor transduces negative signal.

The high-affinity IL-2R results from the noncovalent association between at least two subunits; alpha (p55) and beta (p70), both of which are capable of binding IL-2 with a low and intermediate affinity, respectively. Although the alpha-chain itself has been shown to be nonfunctional, suggestions have been made that the beta-chain mediates an IL-2 signal. To directly study the role of the beta-chain in the signal transduction, we transfected with the cDNA encoding the IL-2R beta-chain a human T lymphotropic virus-I-transformed T cell line, MT-1 originally expressing low-affinity alpha-chain alone, and established a stable transformant (designated MT-beta 7) which expressed both alpha- and beta-chains simultaneously. We showed 1) MT-beta 7 manifested the high-affinity IL-2 binding, which was completely disrupted by the anti-beta chain mAb (Mik-beta 1), 2) the 125I-IL-2 crosslinking patterns of MT-beta 7 were indistinguishable from those of cells expressing the native high-affinity IL-2R, 3) MT-beta 7, but not parental MT-1, internalized the bound IL-2 and responded to IL-2 with a negative signal, i.e., inhibition of the de novo DNA synthesis. These results clearly demonstrate that the beta-chain not only participates in forming the high-affinity IL-2R with the alpha-chain but also is directly involved in the IL-2 signal transduction.

Cell Line↗
PubMed1989

Interleukin-2 receptor beta chain gene: generation of three receptor forms by cloned human alpha and beta chain cDNA's.

Interleukin-2 (IL-2) binds to two distinct receptor molecules, the IL-2 receptor alpha (IL-2R alpha, p55) chain and the newly identified IL-2 receptor beta (IL-2R beta, p70-75) chain. The cDNA encoding the human IL-2R beta chain has now been isolated. The overall primary structure of the IL-2R beta chain shows no apparent homology to other known receptors. Unlike the IL-2R alpha chain, the IL-2R beta chain has a large cytoplasmic region in which a functional domain (or domains) mediating an intracellular signal transduction pathway (or pathways) may be embodied. The cDNA-encoded beta chain binds and internalizes IL-2 when expressed on T lymphoid cells but not fibroblast cells. Furthermore, the cDNA gives rise to the generation of high-affinity IL-2 receptor when co-expressed with the IL-2R alpha chain cDNA.

Amino Acid Sequence↗
PubMed1989

Involvement of both Tac and non-Tac interleukin 2-binding peptides in the interleukin 2-dependent proliferation of human tumor-infiltrating lymphocytes.

Interleukin 2 (IL-2) receptor expression was examined on recombinant IL-2 (rIL-2)-propagated tumor-infiltrating lymphocytes (TIL) from eight metastatic melanoma and three sarcoma samples. All 11 TIL expanded with similar growth rates. rIL-2 propagated TIL from five of eight metastatic melanoma specimens contained no Tac antigen-positive lymphocytes as determined by immunofluorescence and flow cytometry performed multiple times during the 4 to 8 week culture period. However, "Tac-negative" TIL did express the non-Tac IL-2-binding peptide, p70-75 as determined by [125I]IL-2 cross-linking and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. IL-2-binding assays revealed that these "Tac-negative" TIL expressed only an intermediate affinity IL-2 receptor. In contrast, TIL from the other three of eight melanoma and all three sarcoma contained one-third Tac-positive cells as assessed by flow cytometry analysis, and expressed surface non-Tac (p70-75) and Tac (p55) peptides by [125I]IL-2 cross-linking. These "Tac-positive" TIL displayed both the high and intermediate affinity IL-2 receptors. However, rIL-2-dependent growth of both "Tac-negative" and "Tac-positive" TIL was significantly inhibited by anti-Tac mAb, suggesting a transient Tac expression on the "Tac-negative" TIL. Additionally, due to the limits of our methodology, we cannot rule out the possibility of a constitutive expression of a low level of Tac, with an indicible expression of higher levels. Addition of culture supernatants from phytohemagglutinin- and phorbol myristate acetate-stimulated peripheral blood mononuclear cells to the "Tac-negative" TIL-induced detectable Tac expression within 48 h. These results indicate that both non-Tac and Tac IL-2 receptors play important roles during IL-2-dependent proliferation of TIL.

Antibodies, Monoclonal↗
PubMed1989

Characterization of the interleukin 2 receptor beta chain using three distinct monoclonal antibodies.

The human high-affinity receptor for interleukin 2 (IL-2) has been proposed as being a membrane complex composed of at least two distinct polypeptide chains: p55 (alpha chain), recognized by the anti-Tac monoclonal antibody (mAb), and p75 (beta chain), both of which are capable of binding IL-2. Whereas the alpha chain itself has been shown to be nonfunctional, the beta chain appears to be pivotal in the IL-2 signal transduction, although the beta chain is otherwise poorly characterized. Three beta chain-specific mAbs, designated Mik-beta 1, -beta 2, and -beta 3, were developed. Mik-beta 1 and -beta 2 completely inhibited the IL-2 binding to the beta chain, whereas Mik-beta 3 immunoprecipitated the beta chain crosslinked with 125I-labeled IL-2. The beta chain immunoprecipitated by these mAbs was revealed to have a Mr of 68,000-72,000. High-affinity IL-2 binding was completely abolished by Mik-beta 1. Although IL-2-dependent T-cell growth at high IL-2 concentrations was not inhibited by the anti-Tac, it was almost completely inhibited by Mik-beta 1 in the presence of the anti-Tac. These results clearly indicate that the beta chain is an indispensable component to the high-affinity IL-2 receptor and is responsible for the IL-2 signal transduction. The beta chain was found to be constitutively expressed without the alpha chain on the surface of peripheral blood Leu-19+ natural killer cells.

Animals↗
PubMed1988

The role of the multichain IL-2 receptor complex in the control of normal and malignant T-cell proliferation.

Antigen-induced activation of resting T cells induces the synthesis of interleukin-2 (IL-2), as well as the expression of specific cell surface receptors for this lymphokine. There are at least two forms of the cellular receptors for IL-2, one with a very high affinity and the other with a lower affinity. We have identified two IL-2 binding peptides, a 55-kd peptide reactive with the anti-Tac monoclonal antibody and a 75-kd non-Tac IL-2 binding peptide. Cell lines bearing either the p55, Tac, or the p75 peptide alone manifested low-affinity IL-2 binding, whereas cell lines bearing both peptides manifested both high- and low-affinity receptors. Fusion of cell membranes from low-affinity IL-2 binding cells bearing the Tac peptide alone with membranes from a cell line bearing the p75 peptide alone generated hybrid membranes bearing high-affinity receptors. We propose a multichain model for the high-affinity IL-2 receptor in which both the p55 Tac and the p75 IL-2 binding peptides are associated in a receptor complex. The p75 peptide is the receptor for IL-2 on large granular lymphocytes and is sufficient for the IL-2 activation of these cells. In contrast to resting T cells, human T-cell lymphotropic virus I-associated adult T-cell leukemia cells constitutively express large numbers of IL-2 receptors. Because IL-2 receptors are present on the malignant T cells but not on normal resting cells, clinical trials have been initiated in which patients with adult T-cell leukemia are being treated with either unmodified or toxin-conjugated forms of anti-Tac monoclonal antibody directed toward this growth factor receptor.

Antibodies, Monoclonal↗
PubMed1987

Contribution of a p75 interleukin 2 binding peptide to a high-affinity interleukin 2 receptor complex.

There are at least two forms of cellular receptors for interleukin 2 (IL-2); one with a very high affinity and the other with a lower affinity. We identified a non-Tac IL-2 binding peptide with a relative molecular weight of 75,000 (p75). Cell lines bearing either the p55 Tac or the p75 peptide alone manifested low-affinity IL-2 binding, whereas a cell line bearing both peptides manifested both high- and low-affinity receptors. After the internalization of labeled IL-2 through high-affinity receptors, the p75 peptide could not be detected by cross-linking studies. Furthermore, fusion of cell membranes from low-affinity IL-2 binding cell lines bearing the Tac peptide alone with membranes from a cell line bearing the p75 peptide alone generated hybrid membranes bearing high-affinity receptors. These results suggest a multichain model for the high-affinity IL-2 receptor in which high-affinity receptors would be expressed when both Tac and p75 IL-2 binding peptides are present and associated in a receptor complex.

Cell Line↗
PubMed1987

The p75 peptide is the receptor for interleukin 2 expressed on large granular lymphocytes and is responsible for the interleukin 2 activation of these cells.

There are at least two interleukin 2 (IL-2) binding peptides: one is the Mr 55,000 peptide (p55) reactive with the anti-Tac monoclonal antibody, and the other is a Mr 75,000 non-Tac IL-2 binding peptide (p75). Independently existing Tac or p75 peptides represent low-affinity IL-2 receptors, whereas high-affinity IL-2 receptors are expressed when both peptides are present and associated in a receptor complex. It has long been known that normal large granular lymphocytes (LGL) or leukemic cells from the patients with abnormal expansions of LGL can be activated by IL-2 not only to more-potent natural killer cells but also to effectors of lymphokine-activated killer (LAK) activity, although they do not express the Tac peptide. In the present study, using cross-linking methodology, we found that normal LGL and leukemic LGL from all individuals tested expressed the p75 IL-2 binding peptide but did not express the Tac peptide. These LGL leukemia cells made proliferative responses to IL-2 but required a much higher concentration than that required for the proliferation of normal phytohemagglutinin-stimulated T lymphoblasts that express high-affinity receptors. Furthermore, the addition of IL-2 to Tac-negative LGL leukemic cells augmented transcription of the Tac gene and induced the Tac peptide. Neither the IL-2-induced proliferation nor the up-regulation of Tac gene expression was inhibited by the addition of anti-Tac. These results strongly suggest that the p75 peptide is responsible for IL-2-induced activation of LGL and that the p75 peptide alone can mediate an IL-2 signal. Thus, the p75 peptide may play an important role in the IL-2-mediated immune response not only by participating with the Tac peptide in the formation of the high-affinity receptor complex on T cells but also by contributing to the initial triggering of LGL activation so that these cells become efficient natural killer and lymphokine-activated killer cells.

Cell Division↗
PubMed1987

Establishment of an interleukin 2-dependent human T cell line from a patient with T cell chronic lymphocytic leukemia who is not infected with human T cell leukemia/lymphoma virus.

We established an interleukin 2 (IL-2)-dependent human T cell line, Kit 225, from a patient with T cell chronic lymphocytic leukemia (T-CLL) with OKT3+, -T4+, -T8- phenotype. Southern blot analysis showed that Kit 225 is not infected with human T cell leukemia/lymphoma virus (HTLV) type I or II, and is probably derived from the major clone in the fresh leukemic cells. Kit 225 cells express a large amount of IL 2 receptors constitutively and their growth is absolutely dependent on IL 2. No other stimuli, such as lectins or antigens, are required for maintaining the responsiveness to IL 2. As abnormal IL 2 receptor expression was also seen originally in the fresh leukemic cells, the establishment of this cell line with IL 2 suggests that IL 2-mediated T cell proliferation is involved in the leukemogenesis of some cases of HTLV-negative T-CLL.

Antigens, Surface↗
PubMed1986

Dissociation of interleukin-2-mediated cell proliferation and interleukin-2 receptor upregulation in adult T-cell leukemia cells.

We studied cell proliferation and interleukin-2 (IL-2) receptor upregulation mediated by exogenous IL-2 in leukemic cells from adult T-cell leukemia (ATL) patients to characterize some aspects of abnormal IL-2 receptor expression in ATL. Leukemic cells from 7 ATL patients examined showed no or very poor proliferative response to IL-2 though they expressed IL-2 receptors without any stimulation. In contrast, ATL leukemic cells cultured with IL-2 for 2 days expressed about twice as many IL-2 receptors as those of cells cultured without IL-2. Thus, in ATL leukemic cells, there seems to be a dissociation between the signal(s) for two different effects mediated by IL-2, cell proliferation and IL-2 receptor upregulation.

Adult↗
PubMed1986

Demonstration of a non-Tac peptide that binds interleukin 2: a potential participant in a multichain interleukin 2 receptor complex.

The interleukin 2 (IL-2) receptor system plays a key role in the T-cell immune response. Although IL-2 binding was reported to be restricted to the Tac peptide, we have identified an IL-2 binding peptide that does not react with anti-human IL-2 receptor monoclonal antibodies, including anti-Tac on MLA 144, a gibbon ape T-cell line. The MLA 144 cell line expressed 6800 IL-2 binding sites per cell with a low (Kd = 14 nM) affinity for human recombinant IL-2. Using cross-linking methodology, we demonstrated that the IL-2 binding peptide on MLA 144 is larger (Mr 75,000) than the Tac peptide, which has a Mr of 55,000. An IL-2 binding peptide of similar size (Mr 75,000) was also identified in addition to the Tac peptide (Mr 54,000-57,000) on Hut 102, a human T-cell lymphotrophic virus I-induced T-cell leukemia line, and phytohemagglutinin-activated normal human and gibbon ape lymphoblasts. Anti-Tac antibody did not block the binding of 125I-labeled IL-2 to MLA 144 cells. However, this antibody abolished the binding of 125I-labeled IL-2 not only to the Tac peptide on Hut 102 cells and normal lymphoblasts but also to the Mr 75,000 IL-2 binding peptide, suggesting that this latter peptide is associated with the Tac peptide to form the high-affinity IL-2 receptor complex.

Animals↗
PubMed1986

Expression of interleukin-2 receptor on T cell chronic lymphocytic leukemia cells and their response to interleukin-2.

We analyzed peripheral blood leukemic cells from six patients with T cell chronic lymphocytic leukemia (T-CLL) with monoclonal antibodies including the anti-Tac antibody, which recognizes the receptor for interleukin 2 (IL 2). The patients were divided into two groups according to the reactivity of the monoclonal antibodies. Leukemic cells from three patients with T-CLL reacted with OKT3 and T4 but not T8, whereas those from the remaining three patients reacted with OKT3 and T8 but not T4. IL 2 receptor, which is expressed on activated T cells but not on resting T cells, was preferentially expressed on T4+ T-CLL cells. The IL 2 receptor on T4+ T-CLL cells was indistinguishable from that on normal activated T cells with respect to molecular weight and downregulation by the anti-Tac antibody. Moreover, fresh T4+ T-CLL cells, but not T8+ T-CLL cells, proliferated in response to exogenous IL 2 without prior activation, and this proliferation was inhibited by the anti-Tac antibody. These results suggest that malignant growth of T4+ T-CLL cells can be regulated by IL 2 not only in vitro but also in vivo.

Adult↗
PubMed1985

Interleukin-2 receptor (Tac antigen) expressed on adult T cell leukemia cells.

We studied the expression of the interleukin-2 (IL-2) receptor and the proliferative response to exogenous IL-2 of peripheral blood leukemic cells from patients with adult T cell leukemia (ATL) in order to see whether IL-2 receptor expressed on ATL cells is different from normal IL-2 receptor and whether it plays a role in the neoplastic growth in ATL. Peripheral blood leukemic cells from 42 patients with ATL examined expressed IL-2 receptors that were detected by anti-Tac monoclonal antibody when examined immediately after the separation of cells or after the culture for 24 or 48 h. The number of anti-Tac binding sites ranged from 3,100 to 11,400 in fresh cells and from 3,600 to 96,000/cell in short-term cultured leukemic cells, whereas phytohemagglutinin-P (PHA-P)-stimulated normal T cells exhibited 6,900-35,000 anti-Tac binding sites per cell. ATL-derived and human T cell leukemia/lymphoma virus, type I (HTLV-I)-infected cell lines such as MT-1 and Hut102 expressed a much higher number of anti-Tac binding sites. Leukemic cells from 15 patients with ATL examined showed no or very poor proliferative response to various concentrations of immunoaffinity-purified IL-2, although they expressed Tac antigen (Ag). Radiolabeled IL-2 binding experiments demonstrated that ATL leukemic cells could bind IL-2, and they expressed both high and low affinity IL-2 receptors, although the number of high affinity IL-2 receptor was much less than that of low affinity IL-2 receptor and that of anti-Tac binding sites. In contrast, leukemic T cells from a patient with T cell chronic lymphocytic leukemia (CLL), in whom HTLV-I infection was not demonstrated, responded as well as PHA-P-stimulated normal T cells, and their IL-2 receptors, unlike ATL cells, were modulated (down regulated) by anti-Tac antibody. No differences were noted between ATL cells and normal activated T cells in one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the IL-2 receptor. Thus, leukemic cells in ATL spontaneously and continuously express IL-2 receptor, which appears to be abnormally regulated and unresponsive to IL-2. These results, taken together with those on normal IL-2 receptors on HTLV-I-negative T-CLL cells, suggest that abnormal expression of the IL-2 receptor in ATL is closely associated with HTLV-I infection and may play a role in the neoplastic growth of ATL cells.

Adult↗
PubMed1985

TCGF (IL 2)-receptor inducing factor(s). I. Regulation of IL 2 receptor on a natural killer-like cell line (YT cells).

A continuous cell line (YT cells) with inducible receptor for T cell growth factor (TCGF)/interleukin 2 (IL 2) was established from a 15-yr-old boy with acute lymphoblastic lymphoma and thymoma. YT cells were tetraploid, having 4q+ chromosomal markers, and proliferated continuously in vitro without conditioned medium (CM) or IL 2. They were weakly positive for OKT9, OKT11, and Tac antigen (Ag), a determinant closely associated with the receptor for IL 2 (IL 2-R), and were negative for OKT1, OKT3, OKT4, and OKT8 Ag. YT cells also expressed HNK-1 Ag and Fc receptors for IgG, which are expressed on natural killer (NK) cells. They retained a killing activity against human cell lines, including K562 (myeloid), T, and B cell lines. Unlike Tac Ag/IL 2-R(+) cell lines derived from adult T cell leukemia (ATL), YT cells were negative for HTLV, as proved by Southern blotting with cDNA for viral DNA. The expression of Tac Ag was markedly enhanced in 18 hr, when YT cells were incubated with CM from PHA-stimulated peripheral blood leukocytes (PBL) or spleen cells, as determined by immunofluorescence by using flow cytometry and binding assay with 125I-anti-Tac antibody (Ab). The binding study with 125I-labeled recombinant IL 2 showed 3.2 X 10(4) IL 2 receptor sites on YT cells precultured with CM. PHA-P and Con A neither agglutinate nor enhance the expression of IL 2-R/Tac antigen on these non-T cell line cells. Furthermore, neither recombinant IL 2 nor gamma-interferon could induce IL 2-R on YT cells, suggesting the presence of a unique IL 2-R inducing factor in PBL or spleen CM. Unlike Tac Ag on HTLV(+), ATL-derived cell lines (Hut-102, MT-1, ATL-2), the expression of Tac Ag on YT cells was down-regulated by anti-Tac Ab. The induction of Tac Ag/IL 2-R on YT cells seemed specific, because the enhancement of Tac Ag expression was not associated with that of Ia Ag and T9/transferrin receptor.

Adolescent↗