Tadashi Namikawa

Chronic experimental allergic encephalomyelitis in guinea pigs induced by proteolipid protein

A chronic experimental allergic encephalomyelitis (EAE) was produced in Hartley guinea pigs with bovine white matter proteolipid protein (PLP), in which the levels of myelin basic protein (MBP) and galactocerebroside (GC) were less than 0.014% and 0.13%, respectively, by our method of purification. Cells of an MBP-specific T-cell line did not proliferate in the presence of 100 micrograms of PLP and antigen-presenting cells. Eleven animals were sensitized with 250 micrograms of PLP in Freunds complete adjuvant. Three guinea pigs developed paraplegia about 45 days after sensitization. Histological examination of the three animals revealed marked demyelinating lesions in the spinal cord, particularly in the dorsal columns and subpial regions of the lateral and anterior columns. Another guinea pig without apparent clinical symptoms had demyelinating plaques in the dorsal columns of the spinal cord and periventricular white matter of the brain. Antibodies to PLP were highly elevated in the animals with demyelinating plaques but antibodies to MBP and GC were not elevated in the serum samples. Skin response to PLP was positive in sensitized animals, but was not related to the clinical state. Since none of four strain 13 guinea pigs developed chronic EAE, it seems to be strain specific. These results suggest that PLP is encephalitogenic and produces demyelination in the central nervous system without contamination by MBP or GC in Hartley guinea pigs.

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.

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.

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.

Lewy body-like inclusions in Onuf's nucleus from two cases of sporadic amyotrophic lateral sclerosis

Lewy body-like inclusions in Onufs neurons from two sporadic cases with amyotrophic lateral sclerosis (ALS) were reported. These inclusions in Onufs neurons as well as those found in the anterior horn cells were immunostained with an anti-ubiquitin antibody. Neuropathological examination of these two cases revealed neuronal loss and associated gliosis in the anterior horn of the spinal cord and hypoglossal nuclei, and degeneration of the corticospinal tract. In addition to Lewy body-like inclusions, ubiquitinated skein-like inclusions, Bunina bodies, or both were observed in the cytoplasm of the remaining neurons in the anterior horn of the spinal cord, and, to a lesser degree, in Onufs nucleus. Spheroids and cord-like thickening of cell processes were also found in the anterior horn of the spinal cord. Histometrical study of Onufs nucleus revealed atrophy and loss of Onufs neurons from Case 1 with a long clinical course. Similar cases of motor neuron disease with or without tract degeneration have been reported, but the presence of Lewy body-like inclusions in Onufs nucleus is reported here for the first time. It is suggested that Onufs nucleus is more or less involved in the degenerative process characteristic of ALS.

Modulation of experimental allergicencephalomyelitis (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.

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.

Failure of serum from recovered rats to prevent enhanced adoptive transfer of experimental allergic encephalomyelitis

The rat is unique among species used for research on experimental allergic encephalomyelitis (EAE) because of the spontaneous recovery which occurs routinely after severe, almost fatal disease. The mechanism of recovery has never been adequately explained although it has been suggested that suppressor cells might play a role in this phenomenon. In another immune system (contact sensitivity) anti-idiotypic antibodies obtained during the recovery phase have been shown to have a protective effect. Adoptive transfer of EAE, which can be markedly enhanced by incubation of sensitized cells with antigen in vitro, offers a convenient tool for investigating mechanisms of recovery. With this system, we have attempted to suppress transfer of disease with serum obtained from recovered rats. In spite of various manipulations of the experimental protocol, including the use of serum plus complement before and after incubation of cells with antigen, we have been unable to demonstrate suppression of disease. We and others recently reported that cells from recovered rats are also capable of enhanced transfer. This permitted the use of autologous serum from individual cell donors. Even in this strictly autologous system, however, no inhibitory effect of serum could be detected.

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.