INITIAL EVENTS IN CNS INFLAMATION AND MODULATION IN IMMUNE MEDIATED DEMYELINATION

This project will investigate initial changes occurring during CNS inflammation associated with immune-mediated demyelination. The hypothesis under test is that intervention in the cascade of cellular and molecular events leading up to disruption of the blood brain barrier (BBB) in MS, and its laboratory model, EAE, might prevent of block progression of disease and lead to clinical amelioration. The test objects will include a congenic strain of mouse adoptively sensitized for chronic relapsing EAE in the CNS of which we are able to identify donor effector cells on the basis of a T cell marker, Thy-1.2. Using this strain, we shall correlate lymphocyte homing to the CNS with adhesion molecule and cytokine expression at the BBB. We shall characterize the effector T cells phenotypically and functionally (e.g. TH1 versus TH2) in vitro following their isolation from the CNS of animals at different stages of EAE and shall examine the effects of these T cells on myelin and glia in vitro. The overall objective of this aim is to develop a strategy to down-regulate proinflammatory events occurring at the BBB and glia in EAE (and ultimately MS), and to this end, we shall test the effects of injections of antibodies to an adhesion molecule and a cytokine involved in early inflammation (alphaICAM-1 and alphaTNTalpha) and the suppressive cytokine IL-10, upon the course of EAE. Adhesion molecule and cytokine expression in the CNS will be evaluated qualitatively and quantitatively, using Western and Northern blotting and PCR analysis. Parallel experiments will be conducted on fresh frozen and fixed CNS tissue from cases of MS to examine whether lesions of different ages display different adhesion molecule pathways and quantitative differences in adhesion and cytokine molecule expression. Cytokine and growth factor receptors, together with markers for apoptosis, will also be sought on oligodendrocytes in acute MS lesions for evidence of oligodendrocyte regeneration. Finally, mice with EAE will be examined immunocytochemically for a role for TcRgammadelta T cells and heat shock proteins in the CNS (described here in pilot data) since TcRgammadelta T cells have been implicated in oligodendrocyte pathology in MS. This combination of experiments on CNS tissue from MS and EAE to analyze cellular and adhesion molecule-related events may afford information of therapeutic import to the human disease.