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Biomedical subjects

K Katamura

Publications and source records attributed to K Katamura.

At least 19 recordsLinked to original sources

ZAP-70 is required for calcium mobilization but is dispensable for mitogen-activated protein kinase (MAPK) superfamily activation induced via CD2 in human T cells.

Stimulation with specific pairs of anti-CD2 antibodies can induce T cell activation and proliferation. In this study, we investigate the significance of ZAP-70 in CD2 signaling using ZAP-70-deficient T cells derived from a CD8-deficient patient and show that ZAP-70 is necessary for cellular proliferation and cytokine production in T cells stimulated via CD2. Biochemical analyses show that CD2 stimulation induces activation of mitogen-activated protein kinase (MAPK) superfamily in ZAP-70-deficient T cells, indicating that a ZAP-70-independent pathway(s) exists for MAPK superfamily activation via CD2. In contrast, intracellular Ca(2+) mobilization and activation of nuclear factor of activated T cells (NFAT) upon CD2 triggering were impaired in T cells lacking ZAP-70. Furthermore, we found that pharmacological Ca(2+) elevation combined with CD2 stimulation restored NFAT activation and subsequent cytokine production in ZAP-70-deficient T cells. These results indicate that in CD2 signaling, ZAP-70 plays an essential role in Ca(2+) mobilization and NFAT activation.

Animals↗

Characterization of the gammac chain among 27 unrelated Japanese patients with X-linked severe combined immunodeficiency (X-SCID).

X-linked severe combined immunodeficiency (X-SCID) is a rare fatal disease that is caused by mutations in the gene encoding the gammac chain. In this study, 27 unrelated Japanese patients with X-SCID were examined in terms of their genetic mutations and surface expression of the gammac chain. Among 25 patients examined, excluding two patients with large deletions, 23 different mutations were identified in the IL2RG gene, including 10 novel mutations. One patient bearing an extracellular mutation and all three of the patients bearing intracellular mutations after exon 7 expressed the gammac chain on the cell surface. Overall, 84% of patients lacked surface expression of the gammac chain leading to a diagnosis of X-SCID.

Antibodies, Monoclonal↗

Autoimmune-related pancreatitis is associated with autoantibodies and a Th1/Th2-type cellular immune response.

BACKGROUND & AIMS: Although autoimmunity may be involved in some cases of pancreatitis, the mechanism is still unknown. To clarify this, we studied serum autoantibodies, subsets of lymphocytes, and the Th1/Th2 balance of cellular immune responses in patients with autoimmune-related pancreatitis (AIP). METHODS: Seventeen patients with AIP (8 men and 9 women; age, 53.2 +/- 13.0 years) were studied. Autoantibodies including antilactoferrin (ALF) or carbonic anhydrase II antibody (ACA-II) were examined using the enzyme-linked immunosorbent assay (ELISA) or the indirect fluorescein antibody method. Intracellular cytokines (interferon gamma and interleukin 4) and subtypes of peripheral blood lymphocytes were examined by flow cytometry and ELISA. RESULTS: More than one autoantibody was observed in all 17 patients. Serum antinuclear antibody was detected in 13 of 17 patients, ALF antibody in 13, ACA-II antibody in 10, rheumatoid factor in 5, and anti-smooth muscle antibody in 3, but antimitochondrial antibody in none. The serum levels of ACA-II and LF antibody were not correlated. HLA-DR(+)CD8(+) and HLA-DR(+)CD4(+) cells were significantly increased in peripheral blood (P < 0.05). CD4(+) cells producing interferon gamma and the secreted levels were significantly increased compared with those in controls (P < 0.05), but interleukin 4 was not increased. CONCLUSIONS: An autoimmune mechanism against CA-II or LF, and Th1-type immune response, may be involved in AIP.

Adult↗

Regulation of CD31 expression and interleukin-4 production by human cord blood CD4+ T cells with interleukin-4 and interleukin-7.

BACKGROUND: T helper 2 cell type cytokines, such as interleukin (IL)-4 and IL-5, play pivotal roles in the development of allergic diseases. However, the mechanism by which naive CD4+ T cells acquire the ability to produce these cytokines remains unclear. Recently, it was reported that IL-7 induces the ability to produce IL-4 as well as interferon (IFN)-gamma and IL-5 in naive CD4+ T cells without TCR stimulation. To further analyze the mechanism of acquiring IL-4-producing ability by naive CD4+ T cells, the effects of IL-7 on human cord blood CD4+ T cells were compared with those of IL-4, which induced the ability to produce IFN-gamma but not IL-4. RESULTS: Interleukin-7 preserved the population of CD4+CD31- T cells in cord blood and induced their IL-4-producing ability without T cell receptor (TCR) stimulation, while IL-4 induced CD31 on CD31- T cells and could not induce their IL-4-producing ability. Both the CD31-inducing effect and the inhibitory priming effect for IL-4-production by IL-4 were also observed after cord blood CD4+ T cells had been primed with IL-7 and acquired the IL-4-producing ability. CONCLUSIONS: Interleukin-7 induced the IL-4-producing ability in naive CD4+CD31- T cells without TCR stimulation, suggesting that the signal transduction via CD31 may have an inhibitory effect on the acquisition of the IL-4-producing ability by cord blood CD4+ T cells in the absence of TCR stimulation.

CD4-Positive T-Lymphocytes↗

Temperature-sensitive ZAP70 mutants degrading through a proteasome-independent pathway. Restoration of a kinase domain mutant by Cdc37.

CD8 deficiency is an autosomal recessive form of severe combined immunodeficiency diseases characterized by the absence of CD8(+) T lymphocytes and impaired T cell functions. We identified two novel mis-sense mutations in the zap70 genes of a CD8-deficiency patient. One mutation (P80Q) affects a residue in an SH2 domain and another (M572L) in the kinase subdomain XI. Both mutations cause a degradation of ZAP70 protein in a temperature-sensitive manner through an ATP-dependent and proteasome-independent pathway. We further demonstrated that Cdc37, a protein kinase-specific chaperone, bound to M572L but not P80Q mutant and restored the expression of the M572L mutant when overexpressed. The restoration of M572L mutant by Cdc37 required the function of HSP90. These results indicate that Cdc37 in conjunction with HSP90 functions as a molecular chaperone for a temperature-sensitive kinase domain mutant of ZAP70.

Adenosine Triphosphate↗

Hypomethylation of the proximal and intronic regulatory regions of the IFN-gamma gene is not essential for its transcription by naive CD4+ T cells cultured with IL-4.

Recently, long-term preculture with IL-4 or IL-7 has been reported to induce IFN-gamma-producing ability in naive CD4+ T cells without stimulation via TCR. The mechanism of IFN-gamma-transcription in naive CD4+ T cells precultured with IL-4 was analyzed and compared with that in typical Th1 cells by focusing on the TATA proximal and first intronic regulatory regions of the IFN-gamma gene. Both regulatory regions in these IL-4-primed naive CD4+ T cells, which produce a large amount of IFN-gamma upon stimulation with PMA and ionomycin, were completely methylated in contrast to the same hypomethylated regions in Th1 cells. DNase I hypersensitive site analysis suggested that both regulatory regions in IL-4-primed naive CD4+ T cells were not active for IFN-gamma-expression. Moreover, we demonstrated that the composition of transcriptional factors that can bind to the proximal regulatory region is different between IL-4-primed naive CD4+ T cells and Th1 cells. These results indicated that the transcriptional machinery involved in the expression of the IFN-gamma gene by CD4+ T cells varied depending on their modes of differentiation in both the responsive regulatory regions and the specific nuclear factors.

CD4-Positive T-Lymphocytes↗

Further characterization of memory T cells existing in a case of CD8 deficiency.

CD8 deficiency is a rare primary immunodeficiency caused by a defect of ZAP-70, which plays a pivotal role in T cell activation. We previously reported the existence of memory phenotype-CD4+ T cells in a case of CD8 deficiency, which demonstrates that activation signals through ZAP-70 are not essential to the phenotypic conversion of T cells from "naive" to "memory." In this study, we further characterized CD45RO+ T cells in a CD8 deficient patient. We showed that the patient's CD45RO+ T cell population had a wide variety of T cell receptor Vbeta-chain gene usage, and contained few clonally expanded T cells, while many clonally expanded T cells were present in the memory T cell population of age-matched healthy children. These results suggest that various kinds of antigens were involved in the differentiation of the patient's T cells, and that the differentiation into memory T cells was not accompanied by profound T cell proliferation. Moreover, our findings confirmed that the patient's CD45RO+CD4+ T cells had acquired effector-cytokine producing ability, indicating that there exists an alternative activation pathway which is independent of ZAP-70 for the acquisition of effector-cytokine producing ability.

CD8 Antigens↗

Existence of activated and memory CD4+ T cells in peripheral blood and their skin infiltration in CD8 deficiency.

CD8 deficiency is a rare primary immunodeficiency caused by the defect of a tyrosine kinase, ZAP-70, which transduces signals from the T cell receptor. We report here a case of CD8 deficiency, having CD4+ T cells with a unique phenotype. The patient's T cells did not respond to anti-CD3 stimulation in vitro, suggesting that they were naive. However, many CD4+ T cells with activated and memory phenotypes, which expressed CD45RO+, HLA-DR+ and CD25+, were present in the peripheral blood, and these cells accumulated in the perivascular area of his infiltrative erythematous skin lesions. The patient's T cells could be activated by a high concentration of phytohaemagglutinin (PHA), indicating the presence of an alternate signalling pathway which bypasses ZAP-70 and activates CD4+ T cells in vivo. The origin and role of activated CD4+ T cells in the pathogenesis involved in the skin lesions are discussed.

CD4-Positive T-Lymphocytes↗

Ataxia-telangiectasia in the Japanese population: identification of R1917X, W2491R, R2909G, IVS33+2T-->A, and 7883del5, the latter two being relatively common mutations.

We analyzed the data regarding six Japanese ataxia-telangiectasia (A-T) patients from four unrelated families, at the DNA level, to search for possible common mutations in the Japanese population. Among eight mutant alleles in the four families, c. 4612del165 (exon 33 skipping) was identified in two alleles, and c. 5749A to T (R1917X), c. 7471T to C (W2491R), c.7883de15, and c. 8725A to G (R2909G) were identified in one allele each. We found no mutations in the other two alleles. The IVS33 + 2T-->A mutation was identified at the genomic level as the cause of exon 33 skipping. We also identified the IVS33 + 2T-->A mutation in a Japanese patient ATL105 who was previously found to be a homozygote of c. 4612del165. W2491R and R2909G mutations were not detected in more than 100 control Japanese alleles. The latter is located in a highly conserved PI-3 kinase domain and is a completely conserved residue among ATM-related proteins. Taken together with previously documented mutations in five other Japanese A-T patients, IVS33 + 2T-->A and 7883del5 were identified in four and five alleles, respectively, in a total of 18 mutant alleles of Japanese A-T patients. These results suggest that these two mutations are relatively common mutations in the Japanese population.

Adolescent↗

IL-4 and prostaglandin E2 inhibit hypomethylation of the 5' regulatory region of IFN-gamma gene during differentiation of naive CD4+ T cells.

We have previously shown that prostaglandin E2 (PGE2) and IL-4 inhibit the priming of IFN-gamma-production during the differentiation of naive CD4+ T cells from human cord blood by different signal-transducing mechanisms. To compare and analyse the molecular mechanisms by which PGE2 and IL-4 inhibit the priming of IFN-gamma production, we investigated the effects of PGE2 and IL-4 on the methylation of the IFN-gamma gene during the in vitro differentiation of naive CD4+ T cells. In human naive CD4+ T cells, which produce primarily IL-2 and a little amount of IFN-gamma, the IFN-gamma gene was methylated. After stimulation via TCR, CD4+ T cells produced IFN-gamma and the CpG dinucleotide contained within the TATA proximal regulatory element of the IFN-gamma gene was partially hypomethylated. Both IL-4 and PGE2 inhibited the hypomethylation of this site and the acquisition of IFN-gamma-producing ability. In contrast to the SnaBI site in the TATA proximal regulatory element, the HpalI site in the first intron of the IFN-gamma gene of the CD4+ T cells from cord blood was completely methylated even after stimulation via TCR. 5-azacytidine restored the IFN-gamma-producing ability of these cells treated with IL-4 and PGE2. These findings suggest that, although the signal transduction that inhibits the priming of IFN-gamma-production is different for each reagent, the protection from hypomethylation of the regulatory region of the IFN-gamma gene is involved in the molecular mechanisms by which these reagents inhibit the priming of IFN-gamma-production during the differentiation of human naive CD4+ T cells.

Azacitidine↗

Prostaglandin E2 and IL-4 provide naive CD4+ T cells with distinct inhibitory signals for the priming of IFN-gamma production.

We investigated the effects of prostaglandin E2 and IL-4 on the acquisition of cytokine-producing ability by naive CD4(+) T cells in human umbilical cord blood. The presence of PGE2 or IL-4 at primary stimulation inhibited the production of IFN-gamma at secondary stimulation, and the combination of these stimuli resulted in cooperative effects. During primary stimulation with anti-CD3, the intracellular cAMP level was elevated in PGE2-treated cells but not in IL-4-treated or control cells. The signal provided by PGE2, but not by IL-4, was inhibited with RpcAMP, indicating that it was mediated by cAMP. After differentiation into Th2-like cells, cAMP levels in PGE2- and IL-4-treated cells were not different. Our results suggest that both PGE2 and IL-4 play important roles with distinct mechanisms in inhibiting the priming of IFN-gamma production of naive CD4(+) T cells.

CD4-Positive T-Lymphocytes↗

IL-7 induces proliferation, variable cytokine-producing ability and IL-2 responsiveness in naive CD4+ T-cells from human cord blood.

We investigated the effects of IL-7 on the proliferation and acquisition of cytokine-producing ability of naive CD4+ T-cells from human cord blood. Naive CD4+CD45RA+ T-cells from human cord blood expressed CDw127 (IL-7R) at higher levels than adult CD4+ CD45RA+ T-cells and produced IL-2 and a small amount of IFN-gamma upon stimulation with PMA and ionomycin. IL-7 induced IL-2-independent proliferation and both Th1- and Th2-type cytokine-producing abilities in cord blood CD4+CD45RA+ T-cells without stimulation via TCR. These results suggest that this IL-7-induced antigen-independent activation mechanism could contribute to maintaining the clonal size of naive T-cells with the potential to differentiate into either Th1 or Th2 cells at the sites of IL-7-expression.

Adult↗

Clinical courses and thyroid conditions in three infants born to a mother with thyroid stimulating-blocking antibodies.

The clinical courses including thyroid conditions of three infants born to a mother with primary hypothyroidism due to Hashimoto's thyroiditis were studied. The mother was positive for both TSH-binding inhibitor immunoglobulins (TBII) and thyroid stimulating-blocking antibodies (TSBAb) in her serum. The first infant died because of septic shock due to fistula formation between the large intestine and the bladder. Serum thyroid hormone levels during the first pregnancy were extremely low because of incomplete replacement therapy with levothyroxine. The second infant had almost normal thyroid function, so that the replacement therapy was not necessary. The third infant had transient and overt primary hypothyroidism. The replacement therapy was carried out for six months after birth. TSBAb activities in this mother were high in the third pregnancy. In general, these activities gradually increases with the clinical course in TSBAb-positive Hashimoto's patients. From these findings, it was suspected that the thyroid conditions in the second and the third infants reflected the natural course of TSBAb activities in this mother.

Adult↗

X-linked severe combined immunodeficiency with gamma delta T cells.

A patient with X-linked severe combined immunodeficiency (X-SCID) was found to have a deletion mutation of a four base pair in the transmembrane domain of the IL-2 receptor gamma chain gene, a subunit shared by the receptors for IL-4, IL-7, IL-9, and IL-15 (common gamma chain; gamma c). He had very few alpha beta T cells but had a considerable number of gamma delta T cells in his peripheral blood. Fluorescence in situ hybridization (FISH) analysis showed that the gamma delta T cells in his peripheral blood were not of maternal origin. He had received a Bacillus Calmette-Guerin (BCG) vaccination before recognition of the disease, and the BCG infection remained quiescent with no reaction for 19 months. After successful bone marrow transplantation, the site of the BCG vaccination showed a reaction, and live BCG were detected. It is useful to consider the relationship between the existence of gamma delta T cells and BCG in this case, and it is suggested that gamma delta T cells may be, in a given situation, less dependent on the gamma c chain than are alpha beta T cells.

Gene Deletion↗

Negative signaling in B cells by surface immunoglobulins.

Cross-linking of surface immunoglobulins generates negative signals that cause B-cell death unless appropriate rescue signals are provided. Surface IgM is the main transducer of the negative signaling, but surface IgD and IgG may also transduce negative signaling when cross-linked intensively. In the surface IgM+, IgD+ human malignant B lymphoma cell lines B104 and DND-39, cross-linking of surface IgM by anti-IgM antibodies induced cell death. Anti-IgM antibody-induced B104 cell death was inhibited by stimulation with alpha- and beta-interferons but not stimulation with anti-CD40 antibody or IL-4, whereas anti-IgM antibody-induced DND-39 cell death was inhibited by stimulation with anti-CD40 antibody but not stimulation with alpha- and beta-interferons. Anti-IgM antibody-stimulated B104 cells had morphologic features compatible with necrosis, whereas anti-IgM antibody-stimulated DND-39 cells showed morphologic features of apoptosis. CD11a/CD54-dependent cell adhesion induced by stimulation with anti-CD40 antibody was involved in anti-CD40 antibody-mediated inhibition of anti-IgM antibody-induced DND-39 cells. In normal human mature B cells, cross-linking of surface IgM induced different signaling consequences, including DNA synthesis or cell division (positive signaling) or cell cycle arrest or death (negative signaling). In this system, too, CD40-transduced signal inhibited anti-IgM antibody-induced negative signaling, and CD11a/CD54-dependent cell adhesion played a role in the rescue process. It is suggested that quantitatively different intensities of surface IgM cross-linking induce qualitatively different signaling consequences; relatively weak cross-linking may induce DNA synthesis; moderate cross-linking may induce DNA synthesis with cell cycle arrest at the G2/M interphase; and intense cross-linking may induce apoptotic cell death. The reasons for this difference are not yet known. Further elucidation of the molecular mechanisms responsible for surface IgM-mediated negative signaling and its rescue signaling may contribute toward development of therapy for allergic disorders by artificial modulation of specific immunoglobulin production.

Animals↗

Prostaglandin E2 at priming of naive CD4+ T cells inhibits acquisition of ability to produce IFN-gamma and IL-2, but not IL-4 and IL-5.

We investigated the effect of prostaglandin E2 on the acquisition of cytokine-producing ability by naive CD4+ T cells in human cord blood. Naive CD4+ T cells were stimulated for 3 days with mouse monoclonal anti-CD3 Ab, then washed and expanded in IL-2-containing medium for 3 more days. These activated T cells produced IL-2, IL-4, IL-5, and IFN-gamma upon stimulation with PMA and ionomycin. PGE2 added at priming of naive T cells inhibited the production of IL-2 and IFN-gamma, but not of IL-4 and IL-5, in a dose-dependent manner. This change in the cytokine production profile induced by PGE2 was maintained in T cells restimulated with anti-CD3 in the absence of PGE2, expanded by IL-2, and stimulated with PMA and ionomycin. The mRNA expression of IFN-gamma and IL-2, but not that of IL-4, was also decreased in these cells. Forskolin and dibutyryl cAMP had a similar effect. PGE2 must exist at an early stage of T cell activation to inhibit priming for IL-2 and IFN-gamma production. PGE2 also showed this effect, even in the presence of exogenous IFN-gamma, at the primary stimulation. These results indicate that PGE2 inhibits the acquisition of the ability to produce IL-2 and IFN-gamma by acting directly on naive T cells. Our results suggest that PGE2 plays a role in facilitating the development of the Th2-type cytokine production profile.

Animals↗

Serum levels of interleukin 4 and soluble CD23 in children with allergic disorders.

UNLABELLED: In order to clarify the clinical significance of serum interleukin 4 (IL-4) levels, we measured serum IL-4 concentrations in allergic and non-allergic children using a highly sensitive sandwich ELISA. The limit of detection of the assay was 0.15 pg/ml in serum samples. Serum IL-4 was detected in 96.3% (53/55) of non-allergic controls, in 92.9% (183/197) of allergic children, in 70% (7/10) of cord blood samples and in 86.7% (26/30) of neonates. The IL-4 levels in sera from non-allergic controls were relatively constant during the ages examined and all samples were under 1.5 pg/ml. In allergic children, the serum levels of IL-4 were significantly elevated, particularly at age 13-24 months. The serum levels of IL-4 did not differ in children with different clinical manifestations of allergy, such as bronchial asthma, and atopic dermatitis. The serum level of soluble CD23 (sCD23) showed an age-dependent change in allergic and non-allergic children and was significantly higher in allergic than in non-allergic infants aged 7 to 12 months, but not in other age groups. There was no significant correlation among serum levels of IL-4, sCD23 and IgE. CONCLUSION: It is suggested that the measurement of serum IL-4 and sCD23 is helpful in the examination of allergic patients in infancy and early childhood, but neither the serum level of IL-4 nor sCD23 directly reflects in vivo IgE production.

Asthma↗