Sulphatide-specific antibody-mediated effects on the transcriptional profile of myelinating cultures

Semenoff, Tiia Anastasia (2014) Sulphatide-specific antibody-mediated effects on the transcriptional profile of myelinating cultures. MSc(R) thesis, University of Glasgow.

Abstract

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) characterised by the formation of chronically demyelinated plaques of gliotic scar tissue associated with varying degrees of axonal injury and loss. The aetiology of MS remains inexplicit but it is now generally thought of as a ‘complex trait’ in which environmental factors disrupt immunological self-tolerance to myelin antigens in genetically susceptible individuals. The most obvious immunological abnormality associated with MS is a sustained intrathecal synthesis of immunoglobulins within the CNS, manifested by presence of oligoclonal bands of immunoglobulins when cerebrospinal fluid is analysed by isoelectric focusing. These immunoglobulins are derived from clonally expanded B cell populations sequestered in the CNS, but their pathophysiological significance remains obscure.

The specificity profile of this intrathecal antibody repertoire is complex; however, an increasing body of evidence indicates a significant component of this repertoire to be specific for lipids, in particular sulphatide. We therefore used a sulphatide-specific mouse monoclonal antibody (mAb) that mimics the specificity profile of components of the intrathecal response in patients to investigate its effects in myelinating cultures derived from embryonic rat spinal cord in vitro. These experiments focused on exploring the effects of mAb O4 in the absence of serum, a model situation which reproduces that seen in the CNS of patients with progressive forms of MS in which blood brain barrier damage is minimal.

We observed mAb O4 had no immediate effect on myelin integrity, but after 10 days inhibited myelination completely, an effect associated with a 50 % increase in the number of Iba-1+ microglia. To explore the underlying mechanism we performed a gene microarray on cultures treated with mAb O4 in the presence and absence of serum as a source of complement. In the absence of serum mAb O4 induced an unexpected pattern of transcriptional responses characterised by induction of many chemokines (including Cxcl13, Cxcl11, Cxcl10, Cxcl9 and Ccl2) and a large number of interferon sensitive genes (ISGs) more commonly associated in the development of innate and adaptive immunity to pathogens in the CNS. These responses were not seen when cultures were treated with mAbs with no known CNS-specificity, and were abolished when serum was added as a source of complement.

These observations identify a novel antibody-dependent mechanism by which components of the intrathecal antibody repertoire may maintain a pro-inflammatory signalling environment in the CNS in the absence of input from the peripheral immune system. If validated in patients, these findings identify the intrathecal B cell repertoire as an important therapeutic target in MS.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: multiple sclerosis, autoantibodies, sulphatide
• Subjects: Q Science > QR Microbiology > QR180 Immunology
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Supervisor's Name: Linington, Professor Christopher
• Date of Award: 2014
• Depositing User: Miss Tiia Anastasia Semenoff
• Unique ID: glathesis:2014-5867
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jan 2015 11:01
• Last Modified: 30 Jan 2015 11:20
• URI: https://theses.gla.ac.uk/id/eprint/5867