MS Abstracts: 3b-2g

Previous studies illustrated the influence of T-Cell subsets on susceptibility or resistance to DeMyelination in the Theiler's Murine EncephaloMyelitis Virus (TMEV) model of Multiple Sclerosis.

Genetic segregation analysis showed a correlation with disease phenotype in this model with particular Vß Genes. In this study we investigated the contribution of specific Vß TCR to the PathoGenesis of virus-induced DeMyelinating Disease.

Spectratype analysis of cells infiltrating the CNS early in infection demonstrated an over-representation of Vß8⁺ T-Cells in mice expressing a susceptible H-2 haplotype.

We infected transgenic mice expressing the Vß8.2 TCR directed against a non-TMEV Antigen and found an increase in DeMyelinating Disease in mice of either susceptible or resistant background compared with littermate controls.

In addition, depletion studies with an anti-Vß8-specific AntiBody in both susceptible (B10.Q) and resistant (C57BL/6) mice resulted in increased DeMyelination.

TCR analysis of VP2-specific cytotoxic T-Cell clones from mice with a resistant genotype identified only the Vß8.1 TCR, suggesting that limited T-Cell diversity is critical to TMEV clearance.

Together, these results support a protective role for Vß8⁺ T-Cells in Virus-induced DeMyelinating Disease.

High-dose IntraVenous ImmunoGlobulin (IVIg) treatment has become a promising Immune therapy that can modulate the Immune System at several levels, including the Complement Cascade.

In relation to Inflammatory DeMyelinating Disease, there is some clinical evidence for the suppression of disease activity by IVIG, while a role in promoting ReMyelination after experimental Myelin damage has been described.

AntiBody and Complement deposition have been implicated in the Immune attack in some cases of Multiple Sclerosis (MS), and to investigate the mechanisms of action of IVIg, we studied the effect of IVIg using the model of Complement-mediated Cell Injury on Oligodendroglia in vitro.

There was no effect on direct Complement Lysis of the Oligodendroglial Cell Line CG4, but AntiBody-dependent Complement damage was inhibited in a dose-dependent manner by IVIg.

These results were confirmed with primary cultures of Oligodendrocyte Precursor Cells (OPC) and Oligodendrocytes.

The addition of excess C1, C3, and C4 did not influence the inhibitory effect of IVIG, implying that binding of these Complement components does not play a role, in contrast to other experimental models of Complement damage.

F(ab')2 ImmunoGlobulin fragments were at least partially responsible for the effect.

We conclude that IVIg may be protective in AntiBody-mediated Complement Injury of Oligodendrocytes and their Progenitors, and that this effect is likely to be mediated via AntiBody binding, rather than interference with Complement activation.

Inhibition of inflammatory mechanisms, as opposed to a direct effect on ReMyelinating Cells, may underlie the role of IVIg in promoting Myelin repair in experimental models.

Sunlight, which is required for Vitamin D biosynthesis, may be protective in Multiple Sclerosis (MS), due to the ImmunoRegulatory Functions of 1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3), the Hormonally active Vitamin D metabolite.

This hypothesis provided the impetus for the experiments reported here investigating mechanisms whereby 1,25-(OH)2D3 may inhibit murine Experimental AutoImmune EncephaloMyelitis (EAE).

Severe EAE was induced, 1,25-(OH)2D3 or mock treatment was administered, and clinical disease, HistoPathological Disease, and EncephalitoGenic Cells in the Central Nervous System (CNS) were analyzed within 24-72 h of the treatment.

The mock-treated mice remained paralyzed (stage 3 EAE) while most Hormone-treated animals regained the partial use of both hind limbs (stage 2 EAE) within 72 h of treatment.

A HistoPathological examination showed the Hormone-treated mice had a 50% decrease in White Matter and Meningeal Inflammation at 72 h post treatment.

A flow cytometric analysis of cell surface markers on Spinal Cord Cells recovered 24 h post treatment showed the mock-treated mice with EAE had about 7.0 +/- 2.3 million Mac-1+ Cells/Cord, whereas the Hormone-treated mice had about 2.1 +/- 2.6 million Mac-1+ Cells/Cord, which was not significantly different from the unmanipulated control mice.

Otherwise, the flow cytometric analysis detected no significant differences between the groups with respect to CD4⁺ or CD8⁺ T-Cells or B-Cells or Macrophages in draining Lymph Nodes or Spinal Cords.

These results are discussed with regard to possible fates for the 5 million Mac-1+ Cells that were rapidly lost from the inflamed CNS in the 1,25-(OH)2D3-treated mice, and the possible beneficial effect of Hormone treatment in resolving acute MS.

A role for 4 Integrins in different forms of the Multiple Sclerosis-like disease Experimental AutoImmune EncephaloMyelitis (EAE) has been demonstrated.

But, the individual contributions of 4ß1, 4ß7, and the related Eß7 Integrin have not been determined.

The P7 Integrins 4ß7 and Eß7 play a central role in Chronic Inflammation, mediating the trafficking, entry, and/or adhesion of Lymphocytes in the inflamed Pancreas and Gut.

And, their Ligands MAdCAM-1, VCAM-1 and E-Cadherin are expressed on Brain Endothelial Cells and/or on MicroVessels in the inflamed Central Nervous System.

Here, we show that an AntiBody directed against the ß7 subunit greatly attenuates a Non-Remitting form of EAE, induced by adoptive transfer of Myelin Oligodendrocyte peptide (MOG35-55)-stimulated T-Cells.

Combinational treatment with both anti-ß7 and 4 Integrin subunit AntiBodies led to more rapid and complete remission than that obtained with anti-4 AntiBody alone.

Potentially implicating a role for Eß7 in disease progression.

Remission correlated with the down-regulation of the Vascular Addressins VCAM-1. MAdCAM-1, and ICAM-1 on Cerebral blood vessels.

Attenuated forms of disease were induced by adoptive transfer of either wild-type EncephalitoGenic T-Cells to ß7-deficient Gene knockout mice, or of ß7-/-EncephalitoGenic T-Cells to wild-type recipients.

The former finding indicates that ß7 + ve recruited cells contribute to disease progression.

Thus 4ß1, 4ß7, and Eß7 Integrins may all play a contributory role in the Progression of Chronic Forms of DeMyelinating Disease.

And, together with their Ligands could represent potential targets for improved treatment of some forms of Multiple Sclerosis.

The Myelin-associated protein, alphaB-Crystallin, is considered a candidate AutoAntigen in Multiple Sclerosis (MS). In the present study, we examined the potential of alphaB-Crystallin to induce Experimental AutoImmune EncephaloMyelitis (EAE) in Lewis rats.

Attempts to induce EAE with either bovine, rat or murine alphaB-Crystallin or alphaB-Crystallin peptides consistently failed. Immunization with either autologous rat or murine alphaB-Crystallin did not trigger any Antigen-specific T-Cell Response.

Immunization with bovine alphaB-Crystallin or a synthetic peptide representing the cryptic Epitope 49-64 did trigger T-Cell responses but these failed to crossreact with autologous rat alphaB-Crystallin.

Examination of Lymphoid tissues of the Lewis rat revealed constitutive expression of alphaB-Crystallin in Thymus, Spleen, and Peripheral Lymphocytes.

Our data show that in Lewis rats, constitutive Lymphoid expression of alphaB-Crystallin is associated with a state of nonresponsiveness to autologous alphaB-Crystallin that effectively controls the development of EAE in response to this Myelin Antigen.

To test the hypothesis that a lower Mean Arterial Pressure (MAP) response during voluntary isometric exercise in Multiple Sclerosis (MS) is related to a dampened muscle metabolic signal.

9 MS and 11 control subjects performed an Isometric Dorsiflexor contraction at 30% maximal voluntary contraction until target failure (endurance time).

We made continuous and noninvasive measurements of Heart Rate and MAP (Finapres) and of intramuscular pH and P(i) (phosphorus Magnetic Resonance Spectroscopy) in a subset of 6 MS and 10 control subjects.

Endurance times and change in Heart Rate were similar in MS and control subjects. The decrease in pH and increase in P(i) were less throughout exercise in MS compared with control subjects, as was the change in MAP response.

Differences in muscle strength accounted for some of the difference in MAP response between groups.

CardioVascular responses during Valsalva and Cold Pressor Tests were similar in MS and control subjects, suggesting that the blunted MAP response during exercise in MS was not due to a generalized DysAutonomia.

The dampened metabolic response in MS subjects was not explained by inadequate central muscle activation.

These data suggest that the blunted Pressor Response to exercise in MS subjects may be largely appropriate to a blunted muscle metabolic response and differences in contracting muscle mass.

High-dose ImmunoAblative ChemoTherapy with Autologous Haematopoietic Cell support might be beneficial in the treatment of intractable forms of MS.

We mobilized PBPC in 11 patients with Secondary/Progressive MS and finally eight patients were grafted after high-dose BEAM ChemoTherapy with either in vitro or in vivo T cell depletion.

Median EDSS and SNRS scores at the time of inclusion were 6.5 (6.5-7.5) and 56 (44-65), respectively.

PBPC mobilization was safe with no serious adverse effects, and without significant aggravation of disability. One patient improved significantly (by 1.0 point on EDSS) after the mobilization.

Two mobilization failures were observed. No life-threatening events occurred during the transplantation.

All grafted patients, except one, at least stabilized their disability status. One patient improved significantly (by 1.5 points on EDSS), two patients improved slightly (by 0.5 points on EDSS), one patient worsened by 1.0 point on the EDSS in 10 months.

Improvement occurred with a delay of 2-4 months. Median EDSS and SNRS of grafted patients at the last follow up were 6.5 (5.5-8.5) and 64 (39-73), respectively with median follow-up of 8.5 months.

Further follow-up is needed to determine the disease course after complete Immune Reconstitution.

Bone Marrow Transplantation (2000) 25, 525-531