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T Tsubata

Publications and source records attributed to T Tsubata.

At least 37 records · Page 2Linked to original sources
PubMed1996

Autoimmune disease of exocrine organs in immunodeficient alymphoplasia mice: a spontaneous model for Sjögren's syndrome.

Mice homozygous for an autosomal recessive mutation aly (alymphoplasia) lack both lymph nodes and Peyer's patches, and show defects in both humoral and cellular immunity. Histopathological analysis revealed chronic inflammatory changes in exocrine organs such as the salivary gland, lacrimal gland, and pancreas of the homozygotes (aly/aly), but not the heterozygotes (aly/+). In these exocrine organs, mononuclear cells consisting mainly of CD4+ T cells infiltrate periductal areas, and, in some cases, the cell infiltration extended to lobules. The inflammatory changes in exocrine organs were transferred by a T cell-enriched fraction of spleen cells from homozygous animals. These results suggest that autoimmune mechanisms mediated by self-reactive T cells may be involved in the inflammatory lesions of various exocrine organs in the homozygous mice, although these mice show immunodeficiency. Inflammatory changes were also observed in the lung of the homozygotes. Since Sjögren's syndrome is characterized by diffuse lymphocyte infiltration in the periductal areas of the lacrimal and salivary glands and is occasionally associated with pulmonary disease, aly/aly mice may serve as a unique spontaneous model of Sjögren's syndrome.

Adoptive Transfer↗
PubMed1996

Expression of the PD-1 antigen on the surface of stimulated mouse T and B lymphocytes.

A mAb J43 has been produced against the product of the mouse PD-1 gene, a member of the Ig gene superfamily, which was previously isolated from an apoptosis-induced T cell hybridoma (2B4.11) by using subtractive hybridization. Analyses by flow cytometry and immunoprecipitation using the J43 mAb revealed that the PD-1 gene product is a 50-55 kDa membrane protein expressed on the cell surface of several PD-1 cDNA transfectants and 2B4.11 cells. Since the molecular weight calculated from the amino acid sequence is 29, 310, the PD-1 protein appears to be heavily glycosylated. Normal murine lymphoid tissues such as thymus, spleen, lymph node and bone marrow contained very small numbers of PD-1(+) cells. However, a significant PD-1(+) population appeared in the thymocytes as well as T cells in spleen and lymph nodes by the in vivo anti-CD3 mAb treatment. Furthermore, the PD-1 antigen expression was strongly induced in distinct subsets of thymocytes and spleen T cells by in vitro stimulation with either anti-CD3 mAb or concanavalin A (Con A) which could lead T cells to both activation and cell death. Similarly, PD-1 expression was induced on spleen B cells by in vitro stimulation with anti-IgM antibody. By contrast, PD-1 was not significantly expressed on lymphocytes by treatment with growth factor deprivation, dexamethasone or lipopolysaccharide. These results suggest that the expression of the PD-1 antigen is tightly regulated and induced by signal transduction through the antigen receptor and do not exclude the possibility that the PD-1 antigen may play a role in clonal selection of lymphocytes although PD-1 expression is not required for the common pathway of apoptosis.

Animals↗
PubMed1996

Antigen receptor-mediated B cell death is blocked by signaling via CD72 or treatment with dextran sulfate and is defective in autoimmunity-prone mice.

Mature B cells undergo programmed cell death when surface (s) Ig is extensively multimerized. A signal that blocks death of B cells is thus required for activation of B cells in response to antigen stimulation. Here we show that only a few diverse transmembrane signals capable of inducing activation and proliferation of B cells blocked sig-mediated death of normal mature B cells, and that there is no correlation between mitogenic activity and the ability to rescue B cells from death. The results suggest that a specific signal is required for abrogating B cell death induced by sig cross-linking. Signaling via IL-4 receptor and CD40, both of which are derived from activated T cells, blocked sig-mediated death, as described previously. Signaling through a B cell antigen CD72, a counter-receptor of the pan-T antigen CD5, also blocked death of anti-Ig-treated mouse spleen B cells. CD72 signal may play a role in survival of B cells at the initial step of T-B interaction, where resting T cells recognize antigens presented by B cells. Moreover, B cell death by anti-Ig was blocked by T cell-independent antigens such as lipopolysaccharide and dextran sulfate, and spleen B cells from New Zealand mice, which are prone to autoantibody-dependent autoimmune diseases, were resistant to sig-mediated death. Mechanisms for blocking sig-mediated death may therefore be required in antibody response to foreign antigens regardless of T independence or T dependence and in autoantibody production.

Animals↗
PubMed1996

Defects of somatic hypermutation and class switching in alymphoplasia (aly) mutant mice.

The alymphoplasia (aly) mutation of mice causes the systemic absence of lymph nodes, Peyer's patches and well-defined lymphoid follicles in the spleen. We found that antibody responses are elicited, albeit weakly, to either T cell-dependent or T cell-independent antigen by aly/aly mutants. However, isotype switching was defective. The T cell-dependent immune response was not elicited in splenectomized aly/aly mice. Neither hypermutation nor germinal center formation was observed in aly/aly mice. These results suggest that T-B collaboration requires either lymph nodes or spleen, and that hypermutation and affinity maturation depend on germinal center formation.

Amino Acid Sequence↗
PubMed1996

T-cell receptor repertoire of infiltrating T cells in lachrymal glands, salivary glands and kidneys from alymphoplasia (aly) mutant mice: a new model for Sjögren's syndrome.

Alymphoplasia (aly) mice are thought to provide a new model for systemic Sjögren's syndrome (SS), since they reveal remarkable infiltration of mononuclear cells into salivary glands, lachrymal glands and kidneys, and show histological findings similar to those in patients with SS. Cell transfer experiments demonstrate that T cells induce the infiltration of mononuclear cells into several tissues in aly mice. To analyse the pathogenesis of cell infiltration in various tissues, we examined T-cell receptor (TCR) V beta usage of T cells in salivary glands, lachrymal glands and kidneys from aly mice, using family-polymerase chain reaction (PCR) and PCR-single-strand conformation polymorphism (SSCP) methods. The results of SSCP demonstrated that the infiltrating T cells in the three organs expanded clonally, suggesting that they proliferate by antigen-driven stimulation. Some TCR V beta genes (V beta 1, 3, 6, 11, 12, 16) were commonly used in salivary glands, lachrymal glands and kidneys, while the V beta 7 gene was specifically expressed in kidneys. SSCP also showed that there were a few shared T-cell clones (V beta 3- and V beta 6-positive cells) among the three tissues. Indeed, sequence analysis of accumulated T cells showed that a conserved amino acid (leucine) at position 98 in the TCR V beta complementary determining region (CDR) 3 was detected in all organs at high frequency (41-57%) and the amino acid sequence motif (LG) was specifically conserved at a frequency of 32% in the three organs. In conclusion, T cells that infiltrate into lachrymal glands, salivary glands and kidneys of aly mutant mice might recognize shared common epitopes in all three organs and a kidney-specific antigen.

Animals↗
PubMed1995

Isolation of Epstein-Barr-virus-transformed lymphocytes producing IgG class monoclonal antibodies using a magnetic cell separator (MACS): preparation of thyroid-stimulating IgG antibodies from patients with Graves' disease.

In autoimmune diseases, IgG class autoantibodies are generally considered to be more pathognomonic than IgM class ones. Although Epstein-Barr virus (EBV)-transformation of lymphocytes is a useful method to obtain human monoclonal autoantibodies, it tends to result predominantly in IgM-producing cells. We depleted IgM+ cells before EBV-transformation with a Magnetic Cell Separator (MACS) in order to increase the chance of acquisition of cells producing IgG class anti-thyrotropin (TSH) receptor antibodies (TRAb). As a result, we obtained four independent B cell clones producing IgG class monoclonal thyroid-stimulating antibodies (TSAb) from three patients with Graves' disease. None of these clones showed any TSH binding inhibitor immunoglobulin (TBII) activity, suggesting independence of TSAb-producing lymphocytes from those producing TBII.

Antibodies, Monoclonal↗
PubMed1995

Administration of interleukin-5 or -10 activates peritoneal B-1 cells and induces autoimmune hemolytic anemia in anti-erythrocyte autoantibody-transgenic mice.

Activation mechanisms of B-1 (Ly-1 B) cells have been suggested to be different from those of conventional B cells. To assess the role of various interleukins (IL) in the activation of B-1 cells, we injected IL-4, IL-5 or IL-10 into nonanemic anti-red blood cells (RBC) autoantibody-transgenic mice, in which conventional B cells are clonally deleted but peritoneal B-1 cells persist without secreting Ig. Intraperitoneal or intramuscular injection of IL-5 or IL-10, but not IL-4, increased the number of antibody-producing peritoneal B-1 cells by four- to five-fold, resulting in increased anti-RBC serum autoantibody and induction of hemolytic anemia. These results suggest that IL-5 or IL-10 may play an important role in the terminal differentiation of B-1 cells into antibody-producing cells in vivo.

Anemia, Hemolytic, Autoimmune↗
PubMed1995

Prevention of autoimmune symptoms in autoimmune-prone mice by elimination of B-1 cells.

Our recent studies on an autoantibody-transgenic mouse line demonstrated that peritoneal B-1 cells are responsible for autoimmune symptoms. However, whether B-1 cells in the peritoneum are generally involved in the pathogenesis of autoimmune disease remains controversial. To test the possible involvement of peritoneal B-1 cells in autoimmune symptoms of autoimmune-prone NZB mice, we eliminated the peritoneal cells by hypotonic shock with repeated i.p. injection of distilled water every 7 days into neonatal or 8-week-old NZB mice. By this treatment, B-1 cells, which self-renew within the peritoneal cavity, are expected to be preferentially eliminated, while other peritoneal cells can be easily supplied from bone marrows after this treatment. Indeed, in distilled water-treated old NZB mice, the number of B-1 cells decreased in spleen as well as in lamina propria of the gut but the numbers of conventional B cells and T cells did not change. Moreover, the production of autoantibodies against erythrocytes significantly decreased and the occurrence of autoimmune hemolytic anemia was reduced in 12-month-old treated NZB mice. Similarly, the elimination of peritoneal cells of NZB/NZW (NZB/W) F1 mice by water injection decreased anti-DNA IgG antibodies in the sera and reduced the pathological changes of the kidney. These results suggest that peritoneal B-1 cells may be a source of autoantibody-producing cells in autoimmune diseases of NZB and NZB/W F1 mice.

Anemia, Hemolytic, Autoimmune↗
PubMed1994

Molecular mechanisms for B lymphocyte selection: induction and regulation of antigen-receptor-mediated apoptosis of mature B cells in normal mice and their defect in autoimmunity-prone mice.

Apoptosis (programmed cell death) has been suggested to be involved in clonal elimination of self-reactive lymphocytes for the normal function of the immune system. By crosslinking the antigen receptor (surface immunoglobulin; sIg) on the peritoneal B cells of normal mice, we found that strong crosslinking of sIg induces apoptosis of mature B cells, suggesting that interaction with membrane-bound self-antigens may eliminate self-reactive mature B cells by apoptosis. Antigen-receptor-mediated B cell apoptosis is blocked when a signal is transduced via the CD40 molecule on the B cell surface. Because the ligand of CD40 (CD40L) is expressed on activated T helper cells, B cells may escape from apoptosis and are activated when the immune system interacts with foreign antigens, which are normally able to activate T helper cells. Moreover, sIg crosslinking fails to induce apoptosis of both bcl-2-transgenic mice and autoimmune-disease-prone New Zealand mice. In these mice, the defect in sIg-mediated apoptosis of mature B cells may allow generation of self-reactive B cells, resulting in pathogenic consequences.

Animals↗
PubMed1994

Oral administration of lipopolysaccharides activates B-1 cells in the peritoneal cavity and lamina propria of the gut and induces autoimmune symptoms in an autoantibody transgenic mouse.

About a half of the antierythrocyte autoantibody transgenic (autoAb Tg) mice, in which almost all B cells are detected in the spleen, lymph nodes, and Peyer's patches, but not in the peritoneal cavity, suffer from autoimmune hemolytic anemia. The occurrence of this disease is strongly linked to production of autoAb by activated peritoneal B-1 cells in the Tg mice. In this study, we have shown that oral administration of lipopolysaccharides (LPS) activated B-1 cells in the lamina propria of the gut as well as the peritoneal cavity in the healthy Tg mice and induced the autoimmune symptoms in all the Tg mice. The activation of peritoneal and lamina propria B-1 cells by enteric LPS is found not only in the anti-RBC autoAb Tg mice and normal mice but also in the aly mice which congenitally lack lymph nodes and Peyer's patches. These results suggest that B-1 cells in the two locations may form a common pool independent of Peyer's patches and lymph nodes, and can be activated by enteric thymus-independent antigens or polyclonal activators such as LPS. The induction of autoimmune hemolytic anemia in the Tg mice by enteric LPS through the activation of B-1 cells in the lamina propria of gut and in the peritoneal cavity suggests that B-1 cells and bacterial infection may play a pathogenic role in the onset of autoimmune diseases.

Administration, Oral↗
PubMed1994

Antigen-receptor cross-linking induces peritoneal B-cell apoptosis in normal but not autoimmunity-prone mice.

BACKGROUND: Programmed cell death (apoptosis) is an essential process in the development of various tissues and seems to be involved in the elimination of self-reactive immature T and B lymphocytes when they interact with self antigens. Indeed, signaling through the antigen receptor of immature T cells induces their apoptotic cell death. Immature B cells have also been shown to be eliminated when they interact with antigens, although the involvement of apoptosis has yet to be demonstrated. In contrast, little is known about the elimination of mature lymphocytes upon interaction with antigens. We have previously demonstrated that Ly1 B cells in the peritoneal cavity of transgenic mice undergo apoptotic cell death upon interaction with antigens. As Ly1 B cells constitute a B-cell lineage distinct from conventional B cells, it is important to know whether conventional B cells also undergo apoptosis upon antigen-receptor cross-linking. RESULTS: Our experiments show that, in vivo, strong cross-linking of cell-surface immunoglobulins induced apoptotic death of normal, mature B cells in the peritoneal cavity, regardless of whether they were conventional or Ly1 B cells. The same treatment did not kill, but rather activated, B cells in bcl-2-transgenic, apoptosis-resistant mice. Peritoneal B cells from autoimmune-disease-prone New Zealand mouse strains were also found to be resistant to cell death induced by surface immunoglobulin cross-linking. CONCLUSION: Self-reactive B cells are eliminated by the binding of antigen at both mature and immature stages. B-cell activation appears to require, in addition to antigen binding, a second signal that induces expression of rescue molecules such as the bcl-2 gene product. Resistance to B-cell apoptosis induced by antigen receptor cross-linking may play a crucial role in the production of autoantibodies and in the pathogenesis of the autoimmune diseases found in the strains of mice used here.

Animals↗
PubMed1994

Lineage marker-negative lymphocyte precursors derived from embryonic stem cells in vitro differentiate into mature lymphocytes in vivo.

We induced differentiation of mouse embryonic stem (ES) cells into lymphoid cells by culturing in methylcellulose, followed by the co-culture with a bone marrow stromal cell line ST2 in the presence of IL-7. These lymphoid cells expressed transcripts of the recombination activating genes, RAG-1 and RAG-2, as well as the C mu gene, although the lymphoid cells did not express surface antigens specific to T or B lymphocytes such as T200, CD4, CD8 and B220, or transcripts of B lymphocyte-specific genes such as lambda 5 and mb-1. D-J rearrangement was detectable in the lymphoid cells differentiated from ES cells in vitro and a sizeable number of both B and T lymphocytes were generated in vivo when the ES-derived lymphoid cells were transferred into RAG-2-deficient mice, which contain no B or T lymphocytes. The results indicate that in the in vitro co-culture system, ES cells give rise to immature lymphocyte precursors which have potentials to differentiate into both mature B and T lymphocytes in vivo. The ES-derived lineage marker-negative lymphocyte precursors would thus provide useful materials for studying early events of lymphopoiesis.

Animals↗
PubMed1993

The bcl-2 gene product inhibits clonal deletion of self-reactive B lymphocytes in the periphery but not in the bone marrow.

To test whether the product of the bcl-2 proto-oncogene blocks clonal deletion of self-reactive B cells, we have generated transgenic mice carrying the bcl-2 gene and the immunoglobulin genes for the anti-erythrocyte 4C8 antibody. In these transgenic mice, clonal deletion of self-reactive immature B cells in the bone marrow was not inhibited in spite of expression of the bcl-2 gene. In contrast, self-antigen-induced clonal deletion of mature self-reactive Ly-1 B (B1) cells in the peritoneal cavity was inhibited in the transgenic mice. These results indicate that the mechanism for clonal deletion of immature self-reactive B cells in the bone marrow differs from that of mature self-reactive B cells in the periphery.

Animals↗
PubMed1993

B-cell apoptosis induced by antigen receptor crosslinking is blocked by a T-cell signal through CD40.

In mice transgenic for an autoantibody, self-reactive B cells have been shown to be eliminated upon interaction with membrane-bound self-antigens in the periphery as well as in the bone marrow, suggesting that both immature and mature B cells are eliminated by multimerization of surface immunoglobulins (sIg). Activation of mature B cells by antigens may thus require a second signal that inhibits sIg-mediated apoptosis. Such a second signal is likely to be provided by T helper cells, because B-cell tolerance is more easily induced in the absence of T helper cells. To assess the molecular nature of the signal that inhibits sIg-mediated apoptosis, we used anti-IgM-induced apoptotic death of WEHI-231 B lymphoma cells as a model system. Here we report that the signal for abrogating sIg-mediated apoptosis is generated by association of the CD40L molecule on T cells with the CD40 molecule on WEHI-231 cells. T-cell help through CD40 may thus determine whether B cells are eliminated or activated upon interaction with antigens.

Animals↗
PubMed1993

Further analyses of epitopes for human monoclonal anti-basement membrane zone antibodies produced by stable human hybridoma cell lines constructed with Epstein-Barr virus transformants.

We previously established Epstein-Barr virus (EBV)-transformed bullous pemphigoid (BP) patient lymphoblastoid cell lines, which produced human monoclonal anti-basement membrane zone antibodies. In the present study, we established two independent human-human hybridomas by fusion of these EBV transformants with a human B-cell line. These hybridomas, designated 5E-HY-4B and 10D-HY-8B, were very stable and showed a high yield of monoclonal antibody (MoAb) secretion. Each cell line was tetraploid and showed combined rearranged segments of immunoglobulin heavy-chain gene derived from both an EBV transformant and a parent cell. Immunoblot analysis showed that the 5E-HY-4B MoAb recognized the 230-kDa BP antigen but that the 10D-HY-8B MoAb did not show any reactivity. In contrast, both MoAbs precipitated the 230-kDa BP antigen with immunoprecipitation. These results indicate that the two MoAbs reacted with different epitopes on the 230-kDa BP antigen: a continuous epitope for the 5E-HY-4B MoAb and a conformation-dependent epitope for the 10D-HY-8B MoAb. This speculation was confirmed at the molecular level by the result that the fusion protein produced by a partial cDNA for the 230-kDa mouse BP antigen reacted with the 5E-HY-4B MoAb but not with the 10D-HY-8B MoAb. Furthermore, the study of the reactivity with fusion proteins of a series of deleted clones restricted the epitope for the 5E-HY-4B MoAb within the region with 114 amino acid residues in the C-terminal domain of the 230-kDa BP antigen.

Antibodies, Monoclonal↗
PubMed1992

Antigen-induced apoptotic death of Ly-1 B cells responsible for autoimmune disease in transgenic mice.

Studies on transgenic mice expressing immunoglobulins against self-antigens have shown that self-tolerance is maintained by active elimination (clonal deletion), functional inactivation (clonal anergy) of self-reactive B cells, or a combination of both. We have established and characterized a transgenic mouse line expressing an anti-erythrocyte autoantibody. In contrast to other autoantibody transgenic lines, about 50% of the animals of this transgenic line suffer from autoimmune disease, indicating a loss of self-tolerance. Here we show that peritoneal Ly-1 B cells (also known as B-1 cells) are responsible for this autoimmune disease in our transgenic mice. A few self-reactive Ly-1 B cells that have somehow escaped the deletion mechanism expand in the peritoneum because of the absence of self-antigen. These Ly-1 B cells are eliminated in vivo by apoptosis once exposed to self-antigen. On the basis of these results we propose a novel autoantibody production mechanism whereby self-reactive B cells sequestered in compartments free of self-antigens may survive, proliferate and be activated for generation of pathogenic autoantibodies in autoimmune diseases.

Anemia, Hemolytic, Autoimmune↗