Masumi Endoh

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.

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.

No effect of anti-leprosy drugs in the prevention of Alzheimer's disease and β-amyloid neurotoxicity

There is continuing controversy as to whether or not anti-leprosy drugs prevent Alzheimers disease (AD). Therefore, we examined the effect of anti-leprosy drugs on the prevalence of AD in leprosy patients, and also investigated the effect of anti-leprosy drugs on amyloid beta-protein (Abeta)-induced neurotoxicity in vitro. The present study suggests that anti-leprosy treatments do not prevent the onset of AD. None of our data found anti-leprosy drugs (dapsone, rifampicin, clofazimine, minomycin or ofloxacin) had any effect on Abeta neurotoxicity. It is now important to examine the infection of Mycobacterium leprae in the central nervous system to clarify the reason for the low prevalence of senile dementia, and low frequency of Abeta deposition in leprosy patients.

Susceptibility to Proteolipid Apoprotein and Its Encephalitogenic Determinants in Mice

We investigated in mice strain differences in induction of experimental allergic encephalomyelitis by proteolipid apoprotein and studied encephalitogenic determinants. SJL/J, C3H/He, CBA/J and A/J mice were high responders, BALB/c and AKR/J mice were moderately susceptible, and DBA/2, B6 and congenic strains of B10 background were low responders. Synthetic peptide 136-150 was encephalitogenic for SJL/J mice, and 215-232 was encephalitogenic for C3H/He mice. These encephalitogenic derterminants are present in the extracellular portion of proteolipid apoprotein in myelin.

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.

Studies of experimental allergic encephalomyelitis in old mice

In old BALB/c mice susceptibility to experimental allergic encephalomyelitis (EAE) with bovine proteolipid apoprotein (PLP) is reduced significantly. Eleven of 21 8-week BALB/c mice developed clinical signs of EAE following injection of PLP but only two of 18 12-month BALB/c mice and one of 19 24-month BALB/c mice showed clinical signs of EAE. Susceptibility to EAE induced by either PLP or bovine myelin basic protein (MBP) also was reduced in old SJL mice. However, the aging process had no effect on the clinical signs of EAE in both strains, if EAE appeared. Some old BALB/c mice developed histologic EAE with significant demyelination without clinical signs. Lymphocyte proliferative response to mitogens and antigens, and interleukin-2 (IL-2) production, also were depressed in the aged mice (24-month BALB/c and 18-month SJL) probably due to the functional defect of T cells, since the function of macrophages as antigen-presenting cells was not affected in the old mice. PLP-sensitized spleen cells (SPC) from 8-week mice were able to adoptively transfer EAE to young and aged recipients. PLP-sensitized T cells from 8-week mice, reconstituted with young or old monocytes, also were able to transfer EAE into young mice. In contrast, spleen cells from aged mice did not induce EAE, so the reduction of EAE susceptibility was mainly explained by the failure of T cell activity. This T cell defect was not restored by exogenous IL-2.

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.

Immunostimulatory Activity of Major Membrane Protein II from Mycobacterium tuberculosis

ABSTRACT Previously, we observed that both major membrane protein II of Mycobacterium leprae (MMP-ML) and its fusion with M. bovis BCG (BCG)-derived heat shock protein 70 (HSP70) (Fusion-ML) are immunogenic and that recombinant BCG secreting either of these proteins effectively inhibits the multiplication of M. leprae in mice. Here, we purified M. tuberculosis-derived major membrane protein II (MMP-MTB) and its fusion with HSP70 (Fusion-MTB) in a lipopolysaccharide-free condition and evaluated their immunostimulatory abilities. Both MMP-MTB and Fusion-MTB activated monocyte-derived dendritic cells (DC) in terms of phenotype and interleukin-12 (IL-12) production, but Fusion-MTB more efficiently activated them than MMP-MTB did. The IL-12 production was a consequence of the ligation of those recombinant proteins with Toll-like receptor 2. The M. tuberculosis-derived and M. leprae-derived recombinant proteins activated naïve T cells of both CD4 and CD8 subsets, but M. tuberculosis-derived proteins were superior to M. leprae-derived proteins and fusion proteins were superior to MMP, regardless of the origin of the protein. Memory-type CD4+ T cells obtained from BCG-vaccinated healthy individuals seem to be primed with MMP-MTB by the vaccination, and both M. tuberculosis-derived recombinant proteins produced perforin-producing CD8+ T cells from memory-type CD8+ T cells. Further, infection of DC and macrophages with M. tuberculosis H37Ra and H37Rv induced the expression of MMP on their surface. These results indicate that M. tuberculosis-derived MMP, as a sole protein or as part of a fusion protein, may be useful for developing new vaccinating agents against tuberculosis.

Alpha-1-antichymotrypsin is not associated with the increased frequency of apolipoprotein-E-epsilon-4 allele in elderly non-demented leprosy patients.

In our previous study, elderly leprosy patients showed a low prevalence of senile dementia of the Alzheimer type, but the frequency of apolipoprotein E (APO-E) σ4 was elevated in non-demented elderly leprosy patients. Recent study has shown that Alzheimer’s disease risk associated with APO-E σ4 is significantly increased by the α1-antichymotrypsin (ACT) genotype AA. Therefore we examined an association between ACT polymorphism and the APO-E σ4 allele in 350 leprosy patients. None of our data showed an association of ACT genotype and APO-E σ4 allele in leprosy patients. The allelic frequencies of the ACT gene did not differ even between demented patients with leprosy and age-matched controls. Our present data suggest that ACT polymorphism is not associated with the increased frequency of APO-E σ4 in leprosy patients.