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Title: Autoantibodies in Multiple Sclerosis.
Author: Littleton, Edward Theodore
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2008
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Abstract:
rvIultiple sclerosis (MS) is an inflammatory disease of the central nervous system, characterised by axonal demyelination and degeneration. Hypothesised as autoimmune, antibodies to neuronal and myelin proteins have been reported, but there is little evidence of pathogenic antibodies against cell membrane targets. The aim of this thesis was to investigate whether MS patient sera contain antibodies against neuronal or oligodendroglial cells, and to develop techniques by which protein antigenic targets on cell membranes could be identified. Forty-one MS sera were tested for IgG binding to rat brain. Antibody binding to whlte matter was more frequent amongst relapsing-remitting MS patients compared to healthy controls, but western immunoblotting of myelin and rat brain extracts failed to demonstrate any specific reactivity of MS sera. One hundred MS sera were tested by immunofluorescence for IgG or IgM binding to the cell surface of neuroblastoma and oligodendroglioma cells. The number of sera containing cell-binding antibodies was not significantly greater amongst MS patients than amongst healthy controls. Using muscle specific tyrosine kinase (MuSK) seropositive myasthenia gravis as an experimental paradigm, an immunoprecipitation technique to isolate cell surface antigenic targets of serum antibodies, employing cell surface biotin labelling, was developed. Immunoprecipitated proteins were visualised with great sensitivity after gel electrophoresis and blotting. Two MS sera were found 'which specifically immunoprecipitated certain proteins, but development of an unbiased mass spectrometry technique for identifying immunoprecipitated proteins proved difficult due to immunoprecipitate impurity. Eventually, a new protocol for immunoprecipitate digestion and purification prior to mass spectrometry allowed reliable identification of MuSK exclusively in immunoprecipitates derived from MuSK seropositive patients. Thus, a clinically relevant cell membrane antigen has been identi?ed using a novel, non-candidate, unbiased proteomic approach. The same versatile techruque could be applied to identify proteins in immunoprecipitates derived from patients with MS or other putative antibody-mediated diseases. II Supplied by The British Library - 'The world's knowledge' I II. 11 has been observed on carbon nanotubes than graphite. The adsorption isotherms follow Langmuir isotherm except cytosine. Mathematical adsorption models devised here reveal that adenine binding onto graphite could be explained by the interaction between neutral base molecules and neutral surfaces. The adsorption is suggested to be goyemed by three factors: solubility, basestacking and the 1t-1t electron interactions. The adsorption onto quartz, gibbsite and feldspar show little or no adsorption but adsorption onto 'halloysite' is strong with the molecules containing cytosine or adenine groups, especially cytosine groups. Nucleotides adsorb the most followed by bases and nucleosides in this case. pH dependence of cytosine adsorption onto halloysite has been analysed by mathematical adsorption models as well, which shows that the whole adsorption constituents two types of adsorption. Type I can be ascribed to the binding between =SiO- and protonated cytosine, or the binding between =SiOH and neutral cytosine independently. Type 2 can be designated to the binding between =SiO- and neutral cytosine. Mathematical model analysis of literature data illustrates that the adsorption ofbases/nucleosides onto montmorillonite could be described by two types of bindings independently: =AIOH groups bind protonated bases/nucleosides, and =AIOH2+ groups bind neutral bases/nucleosides.- Graphite could prefer to concentrate nucleosides while halloysite could favour nucleotides accumulation. Carbon nanotubes and halloysite, which are both tubular, could have facilitated biomolecules adsorption from diluted primitive oceans. Although no new ideas have been discovered in the process of origins of life, the adsorption difference onto different minerals have shown the importance of minerals in concentrating, selecdng and possible protecting and storing prebiotic biomolecules.
Supervisor: Not available Sponsor: Not available
Qualification Name: University of Oxford, 2008 Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.491344  DOI: Not available
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