William F. Hickey, MD, University of Vermont - US grants

In this proposal for competitive renewal of award RO1-NS-27321, there are two broad goals: (a) define the lymphocyte surface molecules responsible for permitting T-lymphoblasts rapid entry into the CNS (and other sites); and (b) characterize the changes occurring in areas of the CNS which are rendered susceptible to inflammation. These aims are established based upon observations made under the present award. Two of these observations are: (a) T-cells readily enter the CNS regardless of MHC compatibility, antigen specificity, or phenotype if they are in the lymphoblast phase - resting/memory cells are excluded; and (b) a site specific model of Wallerian degeneration will alter a specific site in the CNS from be inflammation resistant to being inflammation susceptible within 24 hours. In reaching the stated goals, many convergent avenues of investigation of both T-cell membrane antigens and tissue molecular changes will be used. These will include both in vivo and in vitro studies. The methods to be employed are: in situ hybridization, monoclonal antibody production, T-cell tissue culture, FACS analysis, and in vivo systems of cytokine infusion, experimental allergic encephalomyelitis, Wallerian degeneration, Graft vs. Host disease, and T-lymphoblast transfer. The results of these studies should be readily applicable to any human illness in which the CNS is damaged by inflammation mediated by T-cells. Examples of such diseases are multiple sclerosis, viral encephalitis and post vaccinial encephalomyelitis.

In this proposal for competitive renewal of award RO1-NS-27321, there are two broad goals: (a) define the lymphocyte surface molecules responsible for permitting T-lymphoblasts rapid entry into the CNS (and other sites); and (b) characterize the changes occurring in areas of the CNS which are rendered susceptible to inflammation. These aims are established based upon observations made under the present award. Two of these observations are: (a) T-cells readily enter the CNS regardless of MHC compatibility, antigen specificity, or phenotype if they are in the lymphoblast phase - resting/memory cells are excluded; and (b) a site specific model of Wallerian degeneration will alter a specific site in the CNS from be inflammation resistant to being inflammation susceptible within 24 hours. In reaching the stated goals, many convergent avenues of investigation of both T-cell membrane antigens and tissue molecular changes will be used. These will include both in vivo and in vitro studies. The methods to be employed are: in situ hybridization, monoclonal antibody production, T-cell tissue culture, FACS analysis, and in vivo systems of cytokine infusion, experimental allergic encephalomyelitis, Wallerian degeneration, Graft vs. Host disease, and T-lymphoblast transfer. The results of these studies should be readily applicable to any human illness in which the CNS is damaged by inflammation mediated by T-cells. Examples of such diseases are multiple sclerosis, viral encephalitis and post vaccinial encephalomyelitis.

DESCRIPTION (Adapted from Applicant's Abstract): Multiple sclerosis (MS) is a chronic CNS disease which produces disability in 0.1% of Caucasian population. No consistently effective therapy is currently available. While immunosuppressive cytokines offer great promise as therapy for MS, the use of these substances is limited because of unacceptable side- effects, inability to get the agents across the blood-brain barrier, or "undesirable effects of the (EAE) is the standard animal model of MS". The investigators propose to use the proprietary encapsulated cell technology of CytoTherapeutics, Inc., to treat rat EAE with the cytokine IL-10. IL-10 has the ability to inhibit EAE, but is most probably not optimal for chronic systemic therapy. Continuous intrathecal delivery of IL-10 should be effective in inhibiting EAE, and should also obviate the problems associated with systemically administered cytokines. The investigator will also examine the effects of long-term IL-10 production in the immune status and function of the CNS. If successful, the first phase of this project will demonstrate the therapeutic efficacy of, and host response to, chronic intrathecal suppression of autoimmune inflammation in the CNS by encapsulated cells secreting recombinant cytokines and will lead to development of an important new medical therapy by US Employers. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE

DESCRIPTION (provided by applicant): For over 15 years the central importance of "perivascular cells" in a variety of neuroimmunological reactions has been recognized. Despite the roles they apparently play in a spectrum of physiological and neuropathological conditions, their exact nature and range of functional possibilities has not been extensively analyzed. Depending on the situation, the perivascular cell can exhibit properties resembling microglial cells, dendritic cells or regular macrophages. This laboratory has a longstanding and productive interest in this resident CNS cell type. In this proposal we wish to define the nature of the perivascular cell more completely. In doing so we will test two hypotheses: (a) that perivascular cells are facultative dendritic cells and possess potential not found in differentiated tissue macrophages; and (b) that these cells are central control elements in governing neural inflammation and CNS immunological activation. Another important and recent discovery is the important, central role of IL-23 in the production of tissue specific inflammation mediated by T cells. In the CNS perivascular cells have receptors for this cytokine and may synthesize it when stimulated. Thus, the role of IL-23 vis-a-vis perivascular cells will also be studied. The proposed investigations will be done through experiments under three specific aims. #1 is to examine the phenotype and products of perivascular cells isolated from the rat CNS. #2 is to determine if PVCs function in distinct ways between divers rat strains that differ relative to their ability to develop CNS inflammation. I1-23 may change this phenotypic difference, or underlie it. #3 is to study the response of PVCs when they confront and present antigen to fully activated T lymphocytes. This is the situation that actually occurs when T cell mediated inflammation is caused in the CNS. As a group, these investigations should more completely elucidate the role of perivascular cells in health and disease, and their relationship to IL-23.