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T Tabira

Publications and source records attributed to T Tabira.

At least 145 records · Page 8Linked to original sources
PubMed1987

Suppression of experimental allergic encephalomyelitis by 15-deoxyspergualin.

15-Deoxyspergualin (DSG), a novel antitumor antibiotic, was tested for treatment of acute experimental allergic encephalomyelitis (EAE) in Lewis rats. Clinical and histologic signs of EAE by active sensitization with myelin basic protein were profoundly inhibited by prophylactic administration of DSG in a dose-dependent manner. By the treatment during the inductive phase, the onset of EAE was significantly delayed. Antigen-specific proliferation of lymph node cells and the ability of spleen cells to transfer EAE were suppressed but concanavalin A-induced lymphocyte proliferation was not altered. Passive EAE induced with an encephalitogenic T cell line was also prevented by DSG-treatment, although DSG did not suppress but rather augmented the activation of T cells in vitro. Taken together, DSG is not a non-specific lymphocyte toxin but a unique immunomodulator that can suppress both inductive and effector phases of EAE.

Animals↗
PubMed1987

Recovery mechanisms from experimental allergic encephalomyelitis in rats: analyses by using encephalitogenic T cell line.

The recovery mechanism of acute experimental allergic encephalomyelitis (EAE) in Lewis rats was studied by using an encephalitogenic T cell line specific for myelin basic protein. Antigen-activated line cells were highly encephalitogenic, but unstimulated line cells were not encephalitogenic. The activated line cells returned to the unstimulated state in a few days in culture medium without antigen. This decline of proliferative and encephalitogenic activities of the activated line cells was also observed even if the activated line cells were continuously stimulated with the antigen. In addition, rats during the convalescent stage from acute EAE showed only mild clinical signs of EAE even by transfer of almost a lethal dose of activated line cells. Thus, self-limiting capacity of autoaggressive cells and attenuation of effector cell function during the convalescent stage seem to be involved in the recovery mechanism of EAE.

Acute Disease↗
PubMed1987

Demyelination induced by T cell lines and clones specific for myelin basic protein in mice.

Neuropathological studies were performed in order to investigate experimental allergic encephalomyelitis induced by long-term cultured T cell lines and clones specific for myelin basic protein, which were established from SJL/J and DDD/1 mice. All antigen-activated T line or clone cells induced similar disease in euthymic and athymic mice with a common I-A haplotype. The lesion was characterized by perivascular and parenchymal infiltration of mononuclear cells with abundant polymorphonuclear cells located mainly in the lower spinal cord. Axons were severely affected and decreased in number. However, demyelination was present in all cases and was especially marked when recipient mice were: given whole-body X-ray irradiation, I-A compatible other strains, or were congenitally athymic. Topographically, demyelinated axons were most prominent in the root exit and entry zones of the lower spinal cord. Repeated transfer or relapse did not seem to be the factor responsible for enhancing demyelination. We conclude that: inflammation with axonal damage is the main feature of murine experimental allergic encephalomyelitis induced by myelin basic protein-specific T cell lines and clones, demyelination definitely occurs under certain conditions and in certain areas especially at the root exit and entry zones in nude mice, and a single T cell clone induces experimental allergic encephalomyelitis lesions associated with demyelination without the aid of interaction with another recipient-derived T cell population.

Animals↗
PubMed1986

DM-20, a proteolipid apoprotein, is an encephalitogen of acute and relapsing autoimmune encephalomyelitis in mice.

Experimental allergic encephalomyelitis (EAE) was successfully induced in BALB/c mice with DM-20, a protein component of proteolipid apoprotein. DM-20 was separated by ion exchange column chromatography with CM-Trisacryl from proteolipid apoprotein obtained from bovine spinal cords. Its purity was ascertained by SDS-polyacrylamide gel electrophoresis, a dot immunobinding procedure, and amino acid analysis. Nine of 15 animals with a single injection of 100 micrograms of DM-20 and five of seven animals with a booster injection developed hind leg paralysis or axial rotatory movement 16 to 27 days after sensitization (mean 21.3 days). Five of the 14 animals relapsed 2 to 6 wk after the first attack. Histological examination revealed inflammatory lesion, with significant demyelination in the central nervous system. Antibody levels to DM-20 were not related to the clinical signs. Five of 11 BALB/c nude mice reconstituted with T cells developed similar clinical and pathologic signs. This DM-20-induced EAE in mice may provide a valuable model because it is similar to multiple sclerosis and because it can be induced in inbred mice in which immune mechanisms can be easily studied.

Acute Disease↗
PubMed1986

Studies of experimental allergic encephalomyelitis by using encephalitogenic T cell lines and clones in euthymic and athymic mice.

The role of T-T cell interactions in the clinical course of acute experimental allergic encephalomyelitis (EAE) in mice was investigated. Myelin basic protein (MBP)-reactive and encephalitogenic T cell clones were established from long-term lines derived from susceptible strain SJL/J mice and resistant strain DDD/1 mice. The lines and clones from DDD/1 mice were obtained by immunization of congenitally athymic mice of DDD/1 origin, which had been reconstituted with syngeneic Lyt-2+-depleted splenic T cells. The clones derived from both strains bore surface phenotypes of Lyt-1+, 2- and L3T4+, and proliferated well in response to rat, rabbit, bovine, and guinea pig MBP in the presence of antigen-presenting cells with I-As. Passive EAE could be induced in syngeneic normal recipients by these clones as well as by the lines from which the clones were derived. The clinical features of the clone-induced EAE were essentially the same as those of the line-induced EAE. Furthermore, DDD/1 athymic recipients developed signs of acute EAE by the adoptive transfer of I-A-compatible syngeneic and allogeneic T cell clones, in which there was no significant difference in time of onset, maximum severity, or prognosis. These results indicate that the entire clinical course of acute EAE can be elicited by a single population of MBP-reactive T cells in the absence of the thymus and other populations of primed or unprimed T cells.

Animals↗
PubMed1986

Antibodies to proteolipid apoprotein in chronic relapsing experimental allergic encephalomyelitis.

Titers of serum antibodies to proteolipid apoprotein (PLP) were determined in chronic relapsing experimental allergic encephalomyelitis (EAE) of strain 13 guinea pigs sensitized with whole central nervous system tissue. Levels of the antibodies were slightly higher in the animals with relapse than those without relapse during the early chronic stage (days 40-99 postinoculation). The titers were significantly higher in the relapsed animals during the chronic stage (days 100-199). Although the clinical course was polyphasic, the humoral response to PLP was monophasic. Since PLP alone causes chronic EAE with widespread demyelination in guinea pigs (Yoshimura et al. 1985), the high titers of anti-PLP antibodies seem to have something to do with the immunologic mechanisms of chronic relapsing EAE.

Animals↗
PubMed1986

Passive transfer of experimental allergic encephalomyelitis induced by proteolipid apoprotein.

In an attempt to obtain insight into the pathogenesis of proteolipid apoprotein (PLP)-induced experimental allergic encephalomyelitis (EAE) in Lewis rats (Yamamura et al. 1986), PLP-sensitized lymph node cells or spleen cells were passively transferred into normal or irradiated (400 rad) recipients after incubation with concanavalin A or PLP. Clinical EAE manifested by paraparesis was successfully transferred into irradiated recipients with 2 - 2.5 X 10(8) of the primary cultured cells and histologic EAE could be transferred with as few as 5 X 10(7) cells into naive recipients. This is the first demonstration of passive EAE induced with PLP-sensitized lymphoid cells and suggests the pathogenetic importance of cell-mediated immunity to PLP.

Animals↗
PubMed1986

Experimental allergic encephalomyelitis induced by proteolipid apoprotein in Lewis rats.

Experimental allergic encephalomyelitis (EAE) was induced in inbred Lewis rats by sensitization with bovine white matter proteolipid apoprotein (PLP). 18-61 days after a single injection of 100 micrograms of PLP, 12 of 31 rats (39%) developed clinical EAE and 18 of 23 (78%) showed pathologic EAE with significant demyelination. Lymphocyte proliferative responses and antibodies to PLP were elevated but did not correlate with the clinical or pathologic state. This is the first demonstration of PLP-induced EAE with significant demyelination in rats and will contribute to the study of autoimmune demyelination.

Animals↗
PubMed1986

Modulation of experimental allergic encephalomyelitis (EAE): suppression of active reinduction of EAE in rats recovered from passively transferred disease.

Lewis rats that have recovered from EAE induced by the passive transfer of in vitro activated lymphocytes sensitized to myelin basic protein showed suppression upon subsequent active reinduction of EAE. This suppression was manifested during the early convalescent stage (up to 30 days after the primary cell transfer) and seemed to be acquired partly idiotype-specifically and partly idiotype-nonspecifically. The convalescent rats were fully susceptible to the transfer of sufficient numbers of effector cells, and they could induce pre-effector cells in response to the encephalitogen in vivo as effectively as in naive rats. This suppression was not transferred to naive rats by lymphoid cells from the convalescent rats. The mechanism of this suppression was thought to be a defect in expansion and/or differentiation of pre-effector cells to effector cells in the convalescent rats.

Animals↗
PubMed1986

A new myelin-deficient mutant hamster: biochemical and morphological studies.

Biochemical and morphological studies were done on a new trembling mutant hamster CBB. The yield of myelin from the mutant was 30 and 40% of the control at 46 and 140 days of age, respectively, but myelin composition and 2',3'-cyclic nucleotide-3'-phosphohydrolase (CNPase) activity were normal. Morphologically, about 18% of the axons were myelinated in the mutant optic nerve at 46 days of age, in which the myelinated fibers were those with larger diameters (more than 0.6 micron), while the control had a peak at 0.4 micron in diameter. The ultrastructure and thickness of compact myelin lamellae in the mutant were normal. Myelination and the structure of peripheral nerve myelin appeared normal. The results indicate that the essential defect is the delay and arrest of myelination in the CNS, which is probably caused by either a decreased rate of synthesis of myelin components in oligodendrocytes or a defect in the oligodendrocyte-axon recognition in smaller axons.

Animals↗
PubMed1986

Activation of effector cells of experimental allergic encephalomyelitis in Lewis rats: comparison of T-cell lines with primary cultured lymph node cells.

We studied the mechanism of activation of effector cells in experimental allergic encephalomyelitis (EAE) by using T-cell lines (EAE/TL) reactive against guinea pig myelin basic protein generated from in vivo primed lymph node cells (LNC) of Lewis rats. EAE-effector cells are activated in the presence of a specific antigen and antigen-presenting cells (APC) with a compatible Ia antigen. The antigen presentation occurs during the first 18 h. EAE-effector cells cannot be activated by allogeneic stimulator cells, but a nonspecific T-cell mitogen, concanavalin A, can activate the effector cells in the presence of syngeneic as well as allogeneic APC.

Animals↗
PubMed1986

Ia expression in chronic relapsing experimental allergic encephalomyelitis induced by long-term cultured T cell lines in mice.

Chronic relapsing experimental allergic encephalomyelitis was induced in SJL mice by adoptive transfer of long-term cultured T cell lines. The T cells which were activated with myelin basic protein (MBP) derived from various species, all induced chronic relapsing experimental allergic encephalomyelitis with a similar high incidence. During the relapsing stage, lymphocytes obtained from the spleen responded well to MBP and were capable of transferring experimental allergic encephalomyelitis, whereas thymus lymphocytes did not respond to MBP. There was no difference in the proliferative response of splenocytes to MBP when splenocytes were isolated either from mice with clinical relapse or from mice that did not relapse. Pathological examination revealed a transient appearance of inflammatory cells during the acute stage. Similar cell infiltrates were also observed at the relapsing stage. The I-region associated (Ia) antigens appeared on vessels and astrocytes in the acute inflammatory lesions which coincided with the appearance of inflammatory cell infiltrates. Ia antigen expression diminished with the disappearance of inflammatory cells. During the relapsing stage, the Ia antigens were also expressed on the vessels and astrocytes in the fresh lesions. Our data indicate that MBP-reactive T cells persist at least in the spleen, for a long time. They may be reactivated by certain mechanisms probably in the central nervous system associated with the Ia-antigen expression, which facilitates the effector phase again. The initial event that triggers the Ia-expression is not known as yet.

Acute Disease↗
PubMed1985

Electron microscopic demonstration of polysaccharides in central and peripheral myelin by thiosemicarbazide-protein-silver staining.

Thin sections of glutaraldehyde-fixed central and peripheral nerve myelin were stained with thiosemicarbazide and protein-silver after oxidation with periodic acid on thin sections. In compact CNS myelin, staining was observed exclusively on intraperiod lines. In peripheral myelin, both intraperiod and major dense lines were stained. In addition, dense staining was observed on plasma membranes of oligodendrocytes and Schwann cells, especially periaxonally on tongue processes and in Schmidt-Lanterman incisures. The observed staining was most prominent on glycogen granules in unfixed and freeze-substituted tissues. Therefore, the results strongly suggest that polysaccharides of glycoproteins and glycolipids are visualized in both CNS and PNS compact myelin as well as on surface membranes of oligodendrocytes and Schwann cells.

Animals↗
PubMed1985

Humoral immune responses to myelin basic protein, cerebroside and ganglioside in chronic relapsing experimental allergic encephalomyelitis of the guinea pig.

Titers of serum antibodies to myelin basic protein, cerebroside and ganglioside were determined in chronic relapsing experimental allergic encephalomyelitis in strain 13 guinea pigs at various intervals after inoculation with whole central nervous system (CNS) tissue. Levels of antibodies to cerebroside and ganglioside were higher in the animals with paralysis than those without paralysis during the early chronic stage. In the late chronic stage, these antibodies were still at high levels, but none of the levels correlated with clinical activity. Levels of antibody to cerebroside were significantly related to the amount of demyelination. The humoral response to the CNS antigens was monophasic, although the clinical course was polyphasic. Another factor seems to be required for clinical relapses in this animal model.

Animals↗
PubMed1985

Ia restriction of murine encephalitogenic T-cell lines in vitro and in vivo.

To clarify the functional role of the I region-associated (Ia) antigen in autoimmune central nervous system disorders, we generated long-term cultured lines of encephalitogenic T cells responsive to myelin basic protein from SJL strain mice (H-2s) and investigated genetic restriction in proliferative and encephalitogenic activities of the lines. These cell lines bear a Lyt 1+,2- phenotype, and show antigen-specific and I-As restricted proliferative responses in vitro. These lines induced full-blown experimental allergic encephalomyelitis (EAE) in immuno-compromised recipients carrying the I-As genotype. These data demonstrate that encephalitogenic T lymphocytes recognize the antigen in combination with the Ia antigen to induce EAE.

Animals↗
PubMed1984

Necessity of continuous antigenic stimulation by the locally retained antigens in chronic relapsing experimental allergic encephalomyelitis.

Chronic relapsing experimental allergic encephalomyelitis has been induced in juvenile strain 13 guinea pigs with isologous spinal cord in Freund's complete adjuvant. Retention of antigen at the injection site and in the draining lymph nodes was studied by immunocytochemical staining with antiserum to myelin basic protein (BP). Antigen was detected in the skin more than 370 days after immunization, whereas it could be detected in the nodes only 200 days postinjection. Amputation of the hind feet to remove the antigenic depots prevented subsequent episodes of clinical EAE. Therefore, continuous antigenic stimulation by the antigen at the local skin site is more important in the induction of relapses than antigen in the draining lymph nodes.

Animals↗