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K Takatsu

Publications and source records attributed to K Takatsu.

At least 91 records · Page 5Linked to original sources
PubMed1995

Evaluation of airway hyperreactivity in interleukin-5 transgenic mice.

Interleukin-5 (IL-5) transgenic mice constitutively produce IL-5 and show massive eosinophilia in peripheral blood as well as infiltration of eosinophils into various tissues. This study investigated whether airway hyperreactivity occurs in the airways of IL-5 transgenic mice. These mice showed marked eosinophilia in bronchoalveolar lavage fluid, but no increase in reactivity to acetylcholine. IL-5 transgenic mice actively sensitized with ovalbumin displayed more profound airway hyperreactivity in response to acetylcholine 24 h after inhalation challenge with ovalbumin. Wild-type mice treated the same way showed little, if any, airway hyperreactivity. These findings indicate that this mouse model of airway hyperreactivity is useful in understanding the mechanism underlying pulmonary eosinophilia and the consequent inflammation.

Acetylcholine↗
PubMed1995

Adhesion molecules on eosinophils in acute eosinophilic pneumonia.

We describe the clinical features, eosinophil surface analysis, and concentration of interleukin-5 (IL-5) in bronchoalveolar lavage (BAL) and in peripheral blood (PB) of a young male patient with acute eosinophilic pneumonia. Eosinophilic pneumonia was diagnosed by BAL and by its clinical course. There was no evidence of an infectious etiology, and the patient showed rapid improvement with methylprednisolone pulse therapy (1 gm/d for 3 d). Significant differences in the expression of surface molecules such as CD54, HLA-DR, and CD69 were observed between BAL and PB eosinophils; IL-5 concentrations in BAL and in PB before treatment were 450 pg/ml and 700 pg/ml, respectively. After treatment, IL-5 concentration in PB was reduced to below 100 pg/ml. The patient has shown no recurrence after treatment.

Acute Disease↗
PubMed1995

Increase in respiratory resistance after exercise in conscious guinea pigs. As a model for exercise-induced asthma.

We have developed an experimental model for exercise-induced asthma (EIA) using conscious guinea pigs. Respiratory resistance (Rrs) was measured before and after exercise (running). When a 0.05% lipopolysaccharide (LPS) was inhaled by guinea pigs which had been pretreated with a corticosteroid biosynthesis inhibitor metyrapone (50 mg/kg, i.v.), Rrs significantly increased 24 h after exercise. Metyrapone had no effect, however, on the LPS-induced increase in the numbers of macrophages, eosinophils, neutrophils and lymphocytes in bronchoalveolar lavage fluid (BALF). In order to examine the role of airway inflammation, the effects of murine recombinant interleukin-5 (mrIL-5) and platelet activating factor (PAF) were investigated in guinea pigs. The exercise-elicited increase in Rrs was observed 24 h later than the treatment with mrIL-5 in metyrapone-treated animals. The number of macrophages, eosinophils and neutrophils increased in the BALF of mrIL-5-treated animals. In contrast, a 0.05% PAF aerosol caused an increased number of eosinophils in BALF, but did not affect Rrs after exercise in either metyrapone-treated or non-treated animals. Moreover, to evaluate the value of this model as a pharmacological tool, the effect of ketotifen and prednisolone on the exercise-induced increase in Rrs was investigated. Prior administration of ketotifen and prednisolone showed a tendency to prevent, or clearly inhibited, the exercise-induced increase in Rrs in animals treated with the combination with LPS and metopyrone.

Airway Resistance↗
PubMed1995

[Structure and function of IL-5 receptor].

Interleukin-5 (IL-5) regulates the production and function of B cells, eosinophils and basophils. In particular, IL-5 plays a critical role in the development of CD5-positive B (B-1) cells. The pleiotropic activity of IL-5 on target cells is directly dependent on the initial binding to IL-5 specific cell-surface receptor (IL-5R). The IL-5 signals are mediated through the high affinity IL-5R which is composed of two different polypeptide chains, alpha and beta. The alpha chain is a membrane-penetrated glycoprotein that specifically binds IL-5 and retains features common to the cytokine receptor superfamily. The beta chain by itself does not bind IL-5, but it can convert the low affinity IL-5R into the high affinity IL-5R and in indispensable for IL-5 signal transduction. The beta chain is shared among receptors for IL-5, IL-3 and GM-CSF and is called beta c. The cytoplasmic comains of both IL-5R alpha and beta c are essential for signal transduction. The membrane proximal proline-rich sequence of the cytoplasmic domain of IL-5R alpha 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 activation of Bruton's tyrosine and JAK2 kinases. Furthermore, JAK2 activation correlates with proline residues in Pro-Pro-X-Pro motif in the cytoplasmic domain of IL-5R alpha. These results indicate that activation of JAK2 and its substrate is critical to coupling IL-5-induced tyrosine phosphorylation and ultimately mitogenesis. I will discuss about molecular mechanisms of IL-5 signaling and B cell defect in X-linked immunodeficient mice in relation to IL-5 signaling.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1995

IL-5 predominant in bronchoalveolar lavage fluid and peripheral blood in a patient with acute eosinophilic pneumonia.

We describe an acute eosinophilic pneumonia (AEP) patient with bronchoalveolar lavage fluid (BALF). Eosinophil cell number (47%), content of interleukin (IL)-5 (8.22 x 10(2) pg/ml) and eosinophil cationic protein (9.25 micrograms/ml) were high in BALF. No eosinophilia was seen in peripheral blood on admission; however, content of IL-5 was 9.47 x 10(2) pg/ml. After methylprednisolone pulse therapy, he improved rapidly with a reduction in eosinophil cell number (7%) and the content of IL-5 (< 100 pg/ml) in BALF. However, a high content of IL-5 (6.9 x 10(2) pg/ml) and transient eosinophilia (17.5%) were seen in peripheral blood. It is important to distinguish between AEP and infectious pneumonia, because of the differing treatments. If the diagnosis of AEP is doubtful, BALF should be performed early.

Acute Disease↗
PubMed1995

A monoclonal antibody against a murine CD38 homologue delivers a signal to B cells for prolongation of survival and protection against apoptosis in vitro: unresponsiveness of X-linked immunodeficient B cells.

A novel monoclonal antibody (mAb) was established in an attempt to look for a cell-surface molecule that delivered a signal regulating apoptotic cell death of B cells. Because spleen cells in resting culture die from apoptosis, mAb were looked for that were able to prolong spleen cell survival in vitro. This screening selected mAb CS/2. CS/2 not only prolonged spleen cell survival in vitro, but also protected spleen cells from apoptotic cell death brought about by irradiation or dexamethasone. Moreover, stimulation of spleen cells with CS/2 mAb induced changes of cells to blastoid morphology, and a significant uptake of [3H]thymidine ([3H]TdR). The antigen recognized by CS/2 mAb (CS/2 Ag) was expressed on preB cells, B cells, and Mac-1+ cells. The cells surviving in vitro culture or irradiation in response to ligation with CS/2 mAb were mostly B cells expressing the CS/2 Ag. In addition, B cells from X-linked immunodeficient (XID) mice did not respond to CS/2 mAb. These results indicate that CS/2 mAb is agonistic to B cells, and that XID mice are deficient in this CS/2 mAb-mediated activation pathway. Determination of the amino-terminal 24 amino acid residues revealed that the CS/2 Ag appears to be identical to the CS/2 mAb is directed against a murine CD38 homologue, and suggest a possible role of the murine CD38 homologue in controlling apoptotic cell death of B cells.

ADP-ribosyl Cyclase↗
PubMed1995

Occurrence of interleukin-5 production by CD4- CD8- (double-negative) T cells in lungs of both normal and congenitally athymic nude mice infected with Toxocara canis.

We studied cells in the lungs of BALB/c and BALB/c-nu/nu (nude) mice infected with Toxocara canis, which produced interleukin-5 (IL-5) in in vitro culture with larval excretory-secretory antigen (ESAg). The proportion of CD4+/CD8+/CD4- CD8- cells in lungs of both BALB/c and nude mice was unchanged before and after infection with T. canis. Panning and complement-mediated lysis using monoclonal antibody (mAb) to CD4 showed that CD4+ cells in the lung from both mice produced IL-5. Anti-CD4 mAb suppressed ESAg-stimulated IL-5 production in vitro. In vitro depletion or inhibition of CD8+ cells reduced IL-5 production significantly in some cases, suggesting involvement with IL-5 production. Anti-CD3 mAb enhanced IL-5 production when incubated with or without ESAg. Production of IL-5 was reduced by in vivo depletion of CD4+ cells only and both CD4+ and CD8+ T cells, by intraperitoneal injection with appropriate mAb; IL-5 production was stimulated by anti-CD3 mAb. In contrast, IL-5 production by lung cells of BALB/c mice decreased by more than 90% after simultaneous injection with anti-CD4, anti-CD8 and anti-CD3 mAb, and was not enhanced by anti-CD3 mAb. Similar results were obtained in nude mice. These results suggest that CD4- CD8- T cells, as well as CD4+ T cells, produce IL-5.

Animals↗
PubMed1995

Mechanisms of eosinophilia in BALB/c-nu/+ and congenitally athymic BALB/c-nu/nu mice infected with Toxocara canis.

We studied the mechanism of eosinophilia in BALB/c-nu/+ (nu/+) and BALB/c-nu/nu (nu/nu) mice infected with Toxocara canis. Eosinophilia with two peaks on days 11 and 21 of infection was observed in infected nu/+ mice, and with a peak on day 11 in nu/nu mice. Interleukin-5 (IL-5) mRNA was expressed on day 5 of infection in the lung and spleen of nu/+ mice and in the lung of nu/nu mice, but not in the spleen of nu/nu mice. Large numbers of eosinophils and lymphocytes infiltrated the lung of both mice 1 week after infection. The number of larvae in the lung was the largest on day 5. Anti-IL-5 monoclonal antibody (mAb) treatment completely inhibited eosinophilia of both mice, with no change of larval distribution. Administration of anti-CD4 or anti-CD3 mAb markedly reduced the second peak of eosinophilia on day 21 of infection in nu/+ mice, and slightly reduced the first peak of eosinophilia on day 11 in both mice. Anti-CD8 mAb had no effect on the eosinophilia. These results suggest that eosinophilia in both mice is caused by IL-5, and that IL-5 is produced by cells other than CD4+ T cells, in addition to CD4+ T cells.

Animals↗
PubMed1995

Elevated innate peripheral blood eosinophilia fails to augment irradiated cercarial vaccine-induced resistance to Schistosoma mansoni in IL-5 transgenic mice.

Numerous factors contribute to host resistance to infection with Schistosoma mansoni. Although several studies have investigated the eosinophil as an effector cell of protective responses, its true role remains unclear. In vitro, human, but not mouse, eosinophils can kill schistosomula. Studies on schistosome infection susceptibility in naive or vaccinated eosinophil-deficient mice have yielded conflicting results. Using the gamma-irradiated cercariae (irr-cerc) model, we vaccinated interleukin (IL)-5 transgenic mice in parallel with background-matched controls (C3H/HeN) to examine whether innate eosinophilia contributes to increased protection from a challenge infection. In our laboratory, mean peripheral blood eosinophil (PBE) levels in IL-5 transgenic mice were 21,000 mm3, whereas in naive C3H/HeN mice this value was 240 mm3. In 3 separate experiments, both groups of vaccinated mice showed significant resistance to challenge infection. However, there was no significant difference in the percent worm reduction between transgenic IL-5 C3H mice (mean % protection = 44.3; range = 42-45%) and the control C3H/HeN mice (mean % protection = 51.7; range = 41-64%). Our findings indicate that high levels of innate PBE due to constitutive production of IL-5 do not augment irr-cerc-stimulated immunity.

Animals↗
PubMed1994

IL-5 receptor-mediated tyrosine phosphorylation of SH2/SH3-containing proteins and activation of Bruton's tyrosine and Janus 2 kinases.

Interleukin 5 (IL-5) induces proliferation and differentiation of B cells and eosinophils by interacting with its receptor (IL-5R) which consists of two distinct polypeptide chains, alpha and beta (beta c). Although both IL-5R alpha and beta c lack a kinase catalytic domain, IL-5 is capable of inducing tyrosine phosphorylation of cellular proteins. We investigated the role of IL-5R alpha in tyrosine phosphorylation of molecules involved in IL-5 signal transduction, using an IL-5-dependent early B cell line, Y16 and transfectants expressing intact or mutant IL-5R alpha together with intact beta c. The results revealed that the transfectants expressing truncated IL-5R alpha, which entirely lacks a cytoplasmic domain, together with beta c, showed neither protein-tyrosine phosphorylation nor proliferation in response to IL-5. This confirms that IL-5R alpha plays a critical role in protein-tyrosine phosphorylation which triggers cell growth. IL-5 stimulation results in rapid tyrosine phosphorylation of beta c and proteins containing Src homology 2 (SH2) and/or SH3 domains such as phosphatidyl-inositol-3 kinase, Shc, Vav, and HS1, suggesting their involvement in IL-5-mediated signal transduction. IL-5 stimulation significantly enhanced activities of Janus 2 and B cell-specific Bruton's tyrosine kinases (JAK2 and Btk) and increased the tyrosine phosphorylation of JAK2 kinase. These results and recent data on signaling of growth factors taken together, multiple biochemical pathways driven by tyrosine kinases such as JAK2 and Btk are involved in IL-5 signal transduction.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1994

Murine B cell proliferation and protection from apoptosis with an antibody against a 105-kD molecule: unresponsiveness of X-linked immunodeficient B cells.

We established a novel monoclonal antibody, RP/14, that can protect B cells from apoptosis induced by irradiation or dexamethasone. A molecule recognized by RP/14 (the RP antigen) was expressed on B cells with B220bright, IgMdull, and IgDbright. Immunoprecipitation experiments revealed that RP/14 recognized a monomeric protein with an approximate molecular mass of 105 kD. Stimulation of B cells with RP/14 for 48 h induced B cell proliferation and blastogenesis. In contrast to B cells of wild-type mice, X-linked immunodeficient (XID) B cells did not proliferate upon stimulation with RP/14, although the RP antigen was expressed to the same extent as that of wild-type B cells. These results suggest that the RP antigen-mediated signaling pathway is important for rescuing B cells from apoptosis and is deficient in XID B cells.

Animals↗
PubMed1994

Biochemical and functional characterization of soluble form of IL-5 receptor alpha (sIL-5R alpha). Development of ELISA system for detection of sIL-5R alpha.

Interleukin-5 (IL-5) mediates pleiotropic functions in various types of cells through its specific receptor (IL-5R) which is composed of two distinct subunits, alpha and beta. In mice, the alpha subunit (IL-5R alpha) specifically binds IL-5 with low affinity. The beta subunit (IL-5R beta) does not bind IL-5 by itself, but constructs the high affinity receptor with IL-5R alpha. We have isolated cDNA encoding the soluble form of IL-5R alpha (sIL-5R alpha). To elucidate the biochemical and functional properties of sIL-5R alpha, we developed an expression system for sIL-5R alpha cDNA in insect cell line Sf21 using baculovirus expression vector and obtained conditioned medium containing large quantities of mouse sIL-5R alpha. Mouse sIL-5R alpha was purified from the conditioned medium by using anti-IL-5R alpha mAb-coupled beads. Immunoaffinity-purified sIL-5R alpha with an approximate molecular mass of 42 kDa inhibited the binding of 125I-labeled IL-5 to IL-5R. By using purified sIL-5R alpha, we prepared rabbit anti-sIL-5R alpha antibody and developed a sandwich ELISA for detection of sIL-5R alpha. Significant amounts of sIL-5R alpha were detected in sera and ascitic fluids of mice bearing tumors (BCL1 and MOPC104E) that responded to IL-5 for DNA synthesis, but not in sera of normal mice. Interestingly, elevated levels of serum sIL-5R alpha were observed in NZB and NZW mice. The sIL-5R alpha may, therefore, have an immunoregulatory role in vivo.

Animals↗
PubMed1994

Regulatory effect of anti-interleukin-5 monoclonal antibody on intestinal worm burden in a primary infection with strongyloides venezuelensis in mice.

The intestinal worm burden in Strongyloides venezuelensis-infected mice was influenced by treatment with anti-interleukin-5 (IL-5) monoclonal antibody (NC17) when NC17 was given to mice 3-7 days before infection. The present study has examined the involvement of IL-5 in susceptibility at different in the development of the parasite in the host. The results show that the number of tissue-migrating larvae recovered from the lungs in a primary infection was not affected by anti-IL-5 monoclonal antibody treatment, whereas intestinal worm counts increased in mice treated with 0.25-1 mg of NC17. In mice treated with 0.1 mg of NC17, adult worm recovery was not significantly different from non-treated controls. Peripheral and tissue eosinophilia were not observed in the early phase of infection (days 4-8). Six days after transfer of lung-stage larvae to NC17-treated mice, adult worm recovery was higher than that of control mice. These results suggest that non-eosinophil response(s), which were dependent on IL-5, were involved in the initial establishment of the intestinal stage of S. venezuelensis in mice. We discuss the mechanisms that control the susceptibility to the parasite from the viewpoint of host defence.

Animals↗
PubMed1994

Detection of interleukin-5 messenger RNA and interleukin-5 protein in bronchial biopsies from asthma by nonradioactive in situ hybridization and immunohistochemistry.

Recently direct evidence for the role of interleukin-5 (IL-5) in eosinophilic inflammation in the airways of persons with asthma has been provided by an in situ hybridization study that used radioisotope-labeled IL-5 complementary RNA probes. Radioisotope-labeled probes, although sensitive, require autoradiographic detection, which is time-consuming. In the most recent study we attempted to detect IL-5 messenger RNA in the bronchial biopsy specimens from patients with asthma using nonradioactive in situ hybridization, which gives rapid results. Bronchial biopsy specimens were obtained from eight patients with asthma and seven diseased control subjects. IL-5 complementary DNA probes were labeled with digoxigenin-deoxyuridine triphosphate and hybridized to permeabilized sections. Hybridization signals were visualized by an immunohistochemistry technique. Positive hybridization signals were observed in six of the eight biopsy specimens from patients with asthma. Pretreatment with ribonuclease or hybridization with an unrelated probe produced negative results. Immunohistochemical staining of serial sections with a monoclonal antibody to IL-5 revealed that a few cells within the mucosa positively stained, suggesting active synthesis of IL-5. Biopsy results from the seven diseased control subjects did not show any hybridization signal. These results confirm and extend previous observations of IL-5 messenger RNA expression in the airways of patients with asthma, and suggest that digoxigenin-labeled IL-5 complementary DNA probes would be a powerful research tool.

Adult↗
PubMed1994

Functional analysis of thymic B cells.

The expression of low- and high-affinity interleukin-5 receptors (IL-5Rs) on thymic B cells and reactivity of thymic B cells to IL-5 was investigated. Thymic B cells consist of two populations (CD5+ and CD5- B cells), as previously described. Three-color FACS analyses using anti-CD5, anti-IgK, and anti-IL-5R mAbs reveal that approximately 60% of both populations (CD5+ and CD5-) in the thymus possess IL-5R, detected by mAb H-7. In Scatchard plot analyses, IL-5Rs on thymic B cells are observed as low affinity receptors; the high-affinity IL-5R, which is known to be expressed on some IL-5-activated splenic B blasts or some IL-5-dependent cell line cells, is not clearly detected on thymic B cells. The reactivity of thymic B cells to IL-5 is found to be significantly lower than that of splenic B cells both in proliferative responses and LPS-induced IgM and IgA antibody responses. These findings are compatible with the expression of the low-affinity IL-5R on thymic B cells. The responsiveness of thymic B cells to either IL-6 or the combination of IL-4, IL-5 and IL-6 is also lower than that of splenic B cells. Furthermore, the thymic B cells are found to induce neonatal tolerance. Therefore, thymic B cells act as antigen-presenting cells in the negative selection of thymocytes, rather than as antibody-producing cells under the influence of foreign antigens and/or regulatory cytokines.

Animals↗
PubMed1994

The murine interleukin-5 receptor alpha-subunit gene: characterization of the gene structure and chromosome mapping.

To understand better the regulation of interleukin-5 receptor alpha-subunit (IL-5R alpha) expression, we have isolated the genomic clones of mouse IL-5R alpha (mIL-5R alpha) and analyzed the structure of the gene. The gene spans more than 35 kb and is composed of 11 exons. We found that two mRNAs encoding secreted forms of mIL-5R alpha result from differential splicing events. We identified the transcriptional start site by primer extension analysis of mIL-5R alpha mRNA. Nucleotide sequence of the 5'-flanking region contains potential binding sites for transcription factor Ap1, AP-1, GATA-1, and PU.1. About 260 bp sequence of the 5'-flanking region exhibited promoter activity when it was linked to a promoterless bacterial chloramphenicol acetyltransferase (CAT) gene. The promoter activity was seen not only in the IL-5-dependent pre-B-cell line Y16, but also in fibroblast cell line NIH-3T3. Comparison of the exon-intron boundaries of mIL-5R alpha genes with those of other members of the cytokine receptor family reveals a conserved evolutionary structure. By fluorescence in situ hybridization analysis, the mIL-5R alpha gene has been assigned to chromosome 6.

Animals↗