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Biomedical subjects

K Takatsu

Publications and source records attributed to K Takatsu.

At least 109 records · Page 6Linked to original sources
PubMed1994

An IFN-gamma-dependent pathway plays a critical role in the pathogenesis of murine immunodeficiency syndrome induced by LP-BM5 murine leukemia virus.

The murine acquired immunodeficiency syndrome (MAIDS) caused by a defective murine leukemia virus produces severe immunodeficiency with abnormal lymphoproliferation and hypergammaglobulinemia. The presence of both CD4+ T cells and B cells is critical for the development of this disease. Remarkably elevated mRNA expression for IFN-gamma and IL-10 was observed in spleen cells of C57BL/6 mice starting from the early phase of viral infection. IFN-gamma production was induced by spleen cells from virus-infected mice upon stimulation with concanavalin A or lipopolysaccharide in both the early and late phases of MAIDS progression. When mice that had been passively administered anti-IFN-gamma mAb were infected with the virus, the development and progression of lymphadenopathy, immunodeficiency and elevated levels of serum IgG2a associated with MAIDS were delayed. Treatment with anti-IL-4 or anti-IL-10 mAb in place of anti-IFN-gamma mAb did not induce the delayed progression of MAIDS. These data support the concept that IFN-gamma-dependent pathway may be involved in the development of MAIDS.

Animals↗
PubMed1994

A critical cytoplasmic domain of the interleukin-5 (IL-5) receptor alpha chain and its function in IL-5-mediated growth signal transduction.

Interleukin-5 (IL-5) regulates the production and function of B cells, eosinophils, and basophils. The IL-5 receptor (IL-5R) consists of two distinct membrane proteins, alpha and beta. The alpha chain (IL-5R alpha) is specific to IL-5. The beta chain is the common beta chain (beta c) of receptors for IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cytoplasmic domains of both alpha and beta chains are essential for signal transduction. In this study, we generated cDNAs of IL-5R alpha having various mutations in their cytoplasmic domains and examined the function of these mutants by expressing them in IL-3-dependent FDC-P1 cells. The membrane-proximal proline-rich sequence of the cytoplasmic domain of IL-5R alpha, which is conserved among the alpha chains of IL-5R, IL-3R, and GM-CSF receptor (GM-CSFR), was found to be essential for the IL-5-induced proliferative response, expression of nuclear proto-oncogenes such as c-jun, c-fos, and c-myc, and tyrosine phosphorylation of cellular proteins including JAK2 protein-tyrosine kinase. In addition, analysis using chimeric receptors which consist of the extracellular domain of IL-5R alpha and the cytoplasmic domain of beta c suggested that dimerization of the cytoplasmic domain of beta c may be an important step in activating the IL-5R complex and transducing intracellular growth signals.

Amino Acid Sequence↗
PubMed1994

IL-5 and its receptor: which role do they play in the immune response?

IL-5 is a homodimeric glycoprotein that promotes proliferation and differentiation of activated B cells, and controls the production and functions of some other hematopoietic cells, such as Ly-1(CD5)+ B cells, eosinophils and basophils. In humans, IL-5 acts as a differentiation and growth factor for eosinophils, and is the major cytokine involved in the production of eosinophilia. IL-5 acts on its target cells through the specific receptor that is composed of two polypeptide chains, a and b. The alpha-chain is unique to IL-5, while the beta-chain is common to IL-5 receptor, IL-3 receptor and granulocyte-macrophage colony stimulating factor (GM-CSF) receptor.

Amino Acid Sequence↗
PubMed1994

Mechanism of eosinophil infiltration in the patient with subcutaneous angioblastic lymphoid hyperplasia with eosinophilia (Kimura's disease). Mechanism of eosinophil chemotaxis mediated by candida antigen and IL-5.

Kimura's disease is a chronic granulomatous disease of unknown etiology. Although eosinophilia is one of the characteristic features in this disease, little is known about the mechanism of eosinophilia. In the present study it was demonstrated that interleukin-5 (IL-5) was produced and released from the site of a granuloma and lymph nodes after stimulation with candida antigen. It was also shown that peripheral blood eosinophils from patients with Kimura's disease contained a large proportion of hypodense eosinophils and that their viability was prolonged. These results strongly suggest that locally produced IL-5 induced by candida antigen contributes to the eosinophilia in this disease.

Adult↗
PubMed1994

Reconstitution of the functional interleukin-5 receptor: the cytoplasmic domain of alpha-subunit plays an important role in growth signal transduction.

The receptor for interleukin-5 (IL-5) is composed of two distinct subunits, alpha and beta. The cDNAs that encode the mouse and human alpha-subunit were transfected into the mouse IL-3-dependent cell line, FDC-P1 expressing the mouse beta-chain intrinsically. The resulting transfectants became responsive to human and mouse IL-5, respectively. Using the mutant alpha-subunits, we found that the alpha-subunit as well as the beta-subunit participated in IL-5-mediated growth signal transduction. The FDC-P1 transfectants expressing the alpha-subunit which lacks its whole cytoplasmic domain did not respond to IL-5, though the interaction of the mutant alpha- and beta-subunits was not impaired. The transfectants expressing the alpha-subunit which lacks the C-terminal half of its cytoplasmic domain proliferated in the presence of IL-5. These results indicate that the transmembrane-proximal cytoplasmic portion of the alpha-subunit plays an important role in IL-5-mediated growth signal transduction.

Animals↗
PubMed1993

Comparative analysis of the kinetics of binding and internalization of IL-5 in murine IL-5 receptors of high and low affinity.

The high affinity IL-5R consists of at least two chains, alpha and beta. IL-5R alpha binds IL-5 with low affinity. IL-5R beta is required to construct the high affinity IL-5R, although IL-5R beta does not bind IL-5 by itself. To characterize the roles of IL-5R alpha and IL-5R beta on the association, dissociation, and internalization of IL-5, we compared the binding kinetics and the internalization of 35S-labeled IL-5 by high affinity IL-5R (dissociation constant approximately 150 pM) bearing T88-M with those by low affinity IL-5R (dissociation constant approximately 30 nM) bearing MOPC104E. We found that association kinetics of IL-5 to either natural receptor were similar. The maximal binding of IL-5 to both high and low affinity IL-5R was rapid (within 10 min). The dissociation of IL-5 from low affinity IL-5R was rapid (t1/2 < 30 min), but that from the high affinity IL-5R was remarkably slower (t1/2 > 120 min). The internalization of IL-5 was observed only in T88-M, but not in MOPC104E, suggesting that IL-5 internalization is mediated via high affinity IL-5R. Association and dissociation kinetics observed in natural cell line were mostly reproduced by the kinetic analysis of reconstituted IL-5R on transfectants with either the IL-5R alpha or the IL-5R alpha and IL-5R beta genes. However, transfectants that expressed IL-5R alpha significantly internalized IL-5, although the level was much lower than observed with IL-5R alpha beta transfectants. These results suggest that IL-5R alpha may be involved in the internalization of IL-5, whereas IL-5R beta is responsible for slowing the dissociation and the efficient internalization of IL-5 by stabilizing the ligand-receptor complex.

Animals↗
PubMed1993

Reconstitution of the functional receptors for murine and human interleukin 5.

The murine interleukin 5 receptor (mIL-5R) is composed of two distinct subunits, alpha and beta. The alpha subunit (mIL-5R alpha) specifically binds IL-5 with low affinity. The beta subunit (mIL-5R beta) does not bind IL-5 by itself, but forms the high-affinity receptor with mIL-5R alpha. mIL-5R beta has been revealed to be the mIL-3R-like protein, AIC2B which is shared with receptors for IL-3 and granulocyte/macrophage colony-stimulating factor. We demonstrated here the reconstitution of the functional receptors for murine and human IL-5 on the mouse IL-2-dependent cell line, CTLL-2. CTLL-2 was transfected with the cDNAs for mIL-5R alpha and/or AIC2B. Only CTLL-2 transfectant expressing both mIL-5R alpha and AIC2B expressed the high-affinity receptor and proliferated in response to murine IL-5. Then CTLL-2 was transfected with the cDNAs for hIL-5R alpha and/or KH97 (beta c), the human homologue of AIC2B. Though beta c did not contribute much to binding affinity of hIL-5R, only CTLL-2 transfectant expressing both hIL-5R alpha and beta c proliferated in response to human IL-5. These results showed that the beta subunit is indispensable in IL-5 signal transduction. We further investigated the function of IL-5-specific alpha subunit in transmitting IL-5 signals. Mutant mIL-5R alpha, which lacks its whole cytoplasmic domain, was transfected into mouse IL-3-dependent cell line, FDC-P1 expressing AIC2B intrinsically. The resulting transfectant did not respond to IL-5, though the transfectant expressed the high-affinity IL-5R, indicating that the cytoplasmic portion of the alpha subunit also has some important role in IL-5-mediated signal transduction.

Animals↗
PubMed1993

In vitro anti-tumor activity of eosinophils from cancer patients treated with subcutaneous administration of interleukin 2. Role of interleukin 5.

Interleukin 2 (IL-2) administration is known to induce marked eosinophilia. To evaluate the potential role of eosinophils as anti-tumor effectors and to understand the direct or indirect effects of IL-2 on eosinophils, the physical and functional characteristics of eosinophils obtained during IL-2 therapy were compared with those of eosinophils obtained from the same patients before IL-2 administration, or from healthy donors. The treatment schedule consisted of subcutaneous (s.c.) injections of IL-2, and was performed in 7 patients with small-cell lung cancer (SCLC) in advanced stage. A marked increase of hypodense cells in peripheral blood was found to correlate with eosinophil activation in patients undergoing IL-2 therapy. Cytotoxic activity of eosinophils against allogeneic tumor cells (SCLC, K562 and melanoma lines), as assessed by direct and antibody (Ab)-dependent cellular cytotoxicity (ADCC), was markedly increased during IL-2 therapy. Conversely, eosinophils obtained before treatment, like those of healthy donors, lacked any activity against tumor cells. Sera from IL-2-treated, but not from untreated, patients, significantly improved the in vitro survival and anti-tumor cytotoxicity of eosinophils from healthy donors. Comparable effects were obtained with eosinophils cultured with interleukin 5 (IL-5), granulocyte-macrophage colony-stimulating factor (GM-CSF) and, to a lesser extent, by tumor necrosis factor-alpha (TNF alpha), while no direct activity was mediated by IL-2. A 91% inhibition of eosinophil ADCC was found after pre-incubation of the sera of IL-2-treated patients with anti-IL-5 but not with anti-GM-CSF or anti-TNF alpha Ab. IL-5 mRNA expression was detected in peripheral-blood lymphocytes (PBL) obtained 4 hr after IL-2 injection during the second and third week of IL-2 therapy. Phenotypic analysis of eosinophils from IL-2-treated patients showed enhanced expression of activation markers, including Fc gamma RII (CD32), HLA-DR, CR3 (CD11b) and CRI (CD35). These findings suggest that a significant cytotoxicity against tumor cells can be mediated by eosinophils after indirect, IL-5-mediated in vivo activation by IL-2, and that eosinophils may be involved in the anti-tumor response(s) induced in vivo by IL-2.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1993

Delayed progression of a murine retrovirus-induced acquired immunodeficiency syndrome in X-linked immunodeficient mice.

The murine acquired immunodeficiency syndrome (MAIDS) caused by defective LP-BM5 murine leukemia virus (MuLV) is a disease that shows severe immunodeficiency with abnormal lymphoproliferation, and hypergammaglobulinemia in susceptible C57BL/6 (B6) mice. To examine the cellular mechanisms of development of MAIDS, we injected LP-BM5 MuLV intraperitoneally into B6 mice bearing the X chromosome-linked immunodeficiency (xid). xid mice lack functionally mature B cells including Ly-1 B cells (also known as B-1 cells). All B6 mice died by 20 wk after LP-BM5 MuLV inoculation. In marked contrast, xid mice have continued to survive without any sign of MAIDS-related symptoms till at least 20 wk after the inoculation. The delayed progression of MAIDS in xid mice appears to depend on xid mutation, according to our experiments using both sexes of (B6.xid x B6)F1 and (B6 x B6.xid)F1 mice. Furthermore, Ly-1 B cells, enriched by a FACS, were shown to integrate the defective genome and appeared to be a major virus-infected B cell population. Our data corroborate that Ly-1 B cells play an important role in the induction and progression of MAIDS.

Animals↗
PubMed1993

Interleukin-5 induces tumor suppression by peritoneal exudate cells in mice.

The antitumor activity of peritoneal exudate cells (PEC) induced by murine interleukin-5 (mIL-5) was examined using Meth-A sarcoma cells transplanted into the peritoneal cavity of mice. Although in vitro treatment of Meth-A sarcoma cells with mIL-5 did not result in inhibition of their growth, treatment of mice intraperitoneally with mIL-5 (1 microgram/day) from day -5 to +5 (tumor cells were inoculated on day 0) led to a significant increase in survival or even rejection of tumor cells. This antitumor effect depended on the dose of mIL-5. Interestingly, there was identical therapeutic activity when the protocol of days -10 to -1 was used as opposed to -5 to +5. In addition, post-treatment with mIL-5 from day +1 to +10 was ineffective. This suggests that the therapeutic activity of IL-5 is largely prophylactic. Under the former condition, the number of PEC was found to increase over 50-fold when compared to levels in control mice. Moreover, the antitumor effect of mIL-5 was completely abolished by subcutaneous injection of anti-mIL-5 monoclonal antibodies. The treatment of mice injected intraperitoneally with human IL-2 also resulted in an increase in survival. Winn assay experiments using PEC recovered from mIL-5-treated mice (1 microgram/day, from day -10 to -1) revealed that these PEC could mediate antitumor activity against Meth-A sarcoma cells. Furthermore, when the cured mice were re-injected with Meth-A sarcoma cells or syngeneic MOPC104E cells, they could reject Meth-A sarcoma cells but not MOPC104E cells, indicating that immune memory had been generated. These results suggest that IL-5 augmented the PEC tumoricidal activity but we have no indication that the tumoricidal activity was mediated through a mIL-5-dependent mechanism.

Animals↗
PubMed1993

Effect of anti-IL-5 monoclonal antibody on allergic bronchial eosinophilia and airway hyperresponsiveness in mice.

The effect of pretreatment with rat anti-murine interleukin-5 (IL-5) antibody on antigen-induced bronchial eosinophilia and bronchial reactivity to acetylcholine in mice were studied. Three inhalations of an antigen by actively sensitized animals resulted in an increase in airway reactivity to acetylcholine. Twenty-four hours after the final inhalation, the number of leukocytes (mononuclear cells and eosinophils) and the amount of IL-5 in BALF increased significantly. Anti-IL-5 monoclonal antibody inhibited the antigen-induced increase of eosinophils with little effect on bronchial hyperreactivity.

Animals↗
PubMed1993

IL-5 receptor positive B cells, but not eosinophils, are functionally and numerically influenced in mice carrying the X-linked immune defect.

Mouse IL-5 (mIL-5) acts on B cells and eosinophils to induce growth and differentiation through the mIL-5 specific receptor (mIL-5R). The functional high-affinity mIL-5R is a heterodimer composed of alpha and beta chains. We investigated the expression of mIL-5R and the responsiveness of B cells and eosinophils to mIL-5 in X-linked immunodeficient (xid) mice. mIL-5R expression analyzed by using mAbs specific for alpha and beta chains revealed that xid B cells had fewer mIL-5R alpha +mIL-5R beta + than BALB/c B cells. In particular, a decrease in the number of peritoneal mIL-5R+ B cells among Ly-1 B cells (known as B-1 cells) was remarkable. Furthermore, the frequency of precursors of mIL-5 responsive B cells in xid mice was approximately 100-fold lower than that of BALB/c mice. Interestingly, sorted mIL-5R+ peritoneal B cells from xid mice displayed a low response to mIL-5. Intraperitoneal injection of mIL-5 into BALB/c mice induced polyclonal IgM production and an increase in the number of eosinophils. The same regimen failed to induce an increase in the same parameters in xid mice. However, xid mice showed mIL-5-induced eosinophilia in peripheral blood to a similar extent as BALB/c mice. Eosinophils from mIL-5-injected xid mice expressed both alpha and beta chains of mIL-5, and responded to mIL-5 with prolonged in vitro survival.

Animals↗
PubMed1993

CD4 T-lymphocyte activation in asthma is accompanied by increased serum concentrations of interleukin-5. Effect of glucocorticoid therapy.

Peripheral blood mononuclear cells (PBMC) and serum were obtained, on two occasions, from 15 asthmatic patients who required oral glucocorticoid therapy for moderate to severe disease exacerbations. Samples were obtained immediately before commencement of oral glucocorticoids (Day 1) and again after 7 days of treatment (Day 7), when lung function had significantly improved. Samples were also isolated on two occasions 7 days apart from a group of seven untreated volunteers. Expression of CD25, human lymphocyte antigen (HLA-)DR, CD45RA, and CD45RO on CD4 and CD8 T lymphocytes was measured by flow cytometry, and serum concentrations of interleukin-5 (IL-5) were measured using an enzyme-linked immunosorbent assay technique. On Day 1 the asthmatic patients showed significantly higher percentages, as compared with the control subjects of CD4 T lymphocytes expressing the markers CD25, HLA-DR, and CD45RO and significantly lower percentages of CD4 T cells expressing CD45RA. After glucocorticoid therapy, the percentages of CD4 T cells expressing CD25, HLA-DR, and CD45RO were significantly reduced in the asthmatic patients, and the percentages of those expressing CD45RA significantly increased so that by Day 7 expression of all four markers was no longer significantly different from that of the control subjects. By contrast, the percentages of CD8 T cells expressing HLA-DR, CD45RA, and CD45RO in the PBMC of the asthmatic patients on Day 1 were not significantly different from those in control subjects, whereas the percentages of CD25 expressing CD8 T cells were only marginally elevated. Glucocorticoid therapy resulted in no significant change in the expression of all four markers on CD T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Novel monoclonal antibodies specific for human cardiac myosin light-chain 1: useful tools for analysis of normal and pathological hearts.

To investigate the developmental, physiological and pathophysiological roles of human cardiac myosin light-chain 1 (LC1s), we developed two novel monoclonal antibodies (KA1 and KB1) against human cardiac LC1s and examined LC1s in normal and pathological hearts immunohistochemically. KA1 and KB1 were specific only for atrial LC1 (ALC1) and for both ALC1 and ventricular LC1 (VLC1), respectively, in human hearts. Among human tissues tested, including skeletal muscle, vascular smooth muscle, and liver, KA1 did not crossreact with proteins in any other tissues than atria, whereas KB1 crossreacted with the slow-type LC1 of skeletal muscle. Among adult mammalian hearts of several other species including pig, dog, hamster, and rat, KA1 and KB1 crossreacted only with ALC1 and with both ALC1 and VLC1, respectively. ALC1 was strongly and uniformly observed in human fetal atria and ventricles and in normal adult human atria, but sporadically in normal adult human ventricles. In the overloaded ventricle (dilated cardiomyopathy), ALC1 was highly augmented but not uniform. These results suggest that the fetal VLC1 is immunohistochemically identical to the adult type of ALC1 and that ALC1 is expressed homogeneously in human fetal ventricles and sporadically in normal adult ventricles, and is re-expressed heterogeneously and in an increased amount in the overloaded ventricle.

Antibodies, Monoclonal↗
PubMed1993

[Cytokine and inflammation: role of IL-5 and its receptor system in inflammation].

The inflammatory response is mediated by various cytokines. IL-5 is one of the inflammatory cytokines. The study of IL-5 has its origins in the search for one of the B-cell differentiation factors, named T-cell-replacing factor (TRF), that induces antigen-stimulated B cells to differentiate into antibody-forming cells. Eosinophil-differentiation factor, EDF, is a factor produced by thoracic duct lymphocytes of parasite-infected rats. cDNA cloning and mAb against IL-5 enable us to identify this molecule as a cytokine (TRF/EDF) that has pleiotropic activity on various target cells besides B cells and eosinophils. The pleiotropic activity of IL-5 is directly dependent on the initial binding to the IL-5 receptor (IL-5R) on the target cell surface. IL-5 transduces its signals through high affinity IL-5R which is constructed by two distinct polypeptides, alpha and beta. IL-5R alpha binds IL-5 with low affinity and associates with the beta chain which can convert low affinity IL-5R to high affinity IL-5R. IL-5R beta that does not bind IL-5 by itself is essential for the IL-5 signaling and is shared among IL-5R, IL-3R, and GM-CSFR. These results imply why IL-5, IL-3, and GM-CSF are eosinophylopoietin. The truncated IL-5R alpha and IL-5R beta complexes can not transduce IL-5 signals, although they bound IL-5 with high affinity, suggesting that IL-5-specific signaling may be transduced through IL-5R alpha.

Animals↗
PubMed1993

[Growth and differentiation of eosinophils--special reference to IL-5 and its receptor].

IL-5 is a 46 KDa glycoprotein secreted from activated T cells, and plays an important role both in the growth and production of eosinophils. Murine eosinophils have been reported to express high and low affinity receptors. The IL-5 receptor is composed of two membrane protein subunits, alpha and beta subunits. Both alpha and beta chain of mouse and human IL-5 receptor have been identified and sequenced. The alpha subunit is a 60 KDa protein which binds to IL-5 with low affinity. The beta subunit is a 130 KDa protein which does not bind to IL-5 by itself, but forms the high affinity IL-5 receptor in the presence of the alpha subunit. On the other hand, only a high affinity receptor population has been identified on human eosinophils. Affinity cross-linking experiments resulted in the identification of human IL-5 receptor on eosinophils with a molecular mass of 55-60 KDa.

Animals↗