A sulfatide-reactive human monoclonal antibody obtained from a multiple sclerosis patient selectively binds to the surface of oligodendrocytes

IgM to phosphatidylcholine in multiple sclerosis patients: from the diagnosis to the treatment

Multiple sclerosis (MS) is a demyelinating and neurodegenerative disease of the central nervous system. It affects young people, and a considerable percentage of patients need the help of a wheelchair in 15 years of evolution. Currently, there is not a specific technique for the diagnosis of MS. The detection of oligoclonal IgG bands (OIgGBs) is the most sensitive assay for it, but it is not standardizable, only reference laboratories develop it, and uses cerebrospinal fluid. To obtain this sample, a lumbar puncture is necessary, an invasive proceeding with important side effects. It is important to develop and implement standard assays to obtain a rapid diagnosis because the earlier the treatment, the better the evolution of the disease. There are numerous modifying disease therapies, which delay the progression of the disease, but they have important side effects, and a considerable percentage of patients give up the treatment. In addition, around 40% of MS patients do not respond to the therapy and the disease progresses. Numerous researches have been focused on the characterization of predictive biomarkers of response to treatment, in order to help physicians to decide when to change to a second-line treatment, and then the best therapeutic option. Here, we review the new biomarkers for the diagnosis and response to treatment in MS. We draw attention in a new assay, the detection of serum IgM to phosphatidylcholine, that showed a similar sensitivity as OIgGBs and predicts the response to disease modifying treatments.

The structural and functional role of myelin fast-migrating cerebrosides: pathological importance in multiple sclerosis

A family of neutral glycosphingolipids containing a 3-O-acetyl-sphingosine galactosylceramide (3-SAG) has been characterized. Seven new derivatives of galactosylceramide (GalCer), designated as fast-migrating cerebrosides (FMCs) by TLC retention factor, have been identified. The simplest compounds - FMC-1 and FMC-2 - of this series have been characterized as the 3-SAG containing nonhydroxy and hydroxy fatty acyl, respectively. The next two - FMC-3 and FMC-4 - add 6-O-acetyl-galactose and the most complex glycosphingolipids, FMC-5, -6 and -7, are 2,3,4,6-tetra-O-acetyl-3-SAG. These hydrophobic myelin lipid biomarkers coappear with GalCer during myelinogenesis and disappear along with GalCer in de- or dys-myelinating disorders. Myelin lipid antigens, including FMCs, are keys to myelin biology, opening the possibility of new and novel immune modulatory tools for treatment of autoimmune diseases including multiple sclerosis.

Lipid autoreactivity in multiple sclerosis

Lipids comprise over 70% of the myelin sheath but have been largely underinvestigated as autoantigens in multiple sclerosis (MS). This paper cites evidence for the involvement of lipid autoreactivity in MS and details how self lipid cross-reactivity may also contribute to the development of type 1 diabetes and autoimmune thyroid disorders (both of which have been associated with MS). A further analysis of myelin chemistry suggests several mechanisms by which infection may contribute to etiology and trigger lipid autoreactivity via molecular mimicry. This analysis may aid the development of new therapies for autoimmune diseases.

Molecular and immunogenic features of myelin lipids: incitants or modulators of multiple sclerosis?

Myelin lipids have long been thought to play intriguing roles in the pathogenesis of multiple sclerosis (MS). This review summarizes current understanding of the molecular basis of MS with emphasis on the: (i.) physico-chemical properties, organization and accessibility of the lipids and their distribution within the myelin multilayer; (ii.) characterization of myelin lipid structures, and structure-function relationships relevant to MS mechanisms, and; (iii.) immunogenic and other features of lipids in MS including molecular mimicry, lipid enzyme genetic knockouts, glycolipid-reactive NKT cells, and monoclonal antibody-induced remyelination. New findings associate anti-lipid antibodies with pathophysiological biomarkers and suggest clinical utility. The structure of CD1d-lipid complexed with the lipophilic invariant T cell receptor (iTCR) may be crucial to understanding MS pathogenesis, and design of lipid antigen-specific therapeutics. Novel immuno-modulatory tools for treatment of autoimmune diseases including MS in which there is both constraint of inflammation and stimulation of remyelination are now emerging.

Monoclonal MOG-reactive autoantibody from progressive EAE has the characteristics of a natural antibody

A.SW mice sensitized with myelin oligodendrocyte glycoprotein (MOG)92-106 is an animal model for progressive multiple sclerosis (MS). We isolated MOG-reactive monoclonal antibodies that were immunoglobulin (Ig)M and polyreactive, similar to natural autoantibodies. Upon analysis of the variable (V) light chains and the diversity (D) and joining (J) regions of V heavy chains, we found they were identical to germ line Vkappa19/28, Jkappa5, DFL16.1e and JH4, respectively. The sequence of the VH region had 99.7% and 100% identity at the nucleotide and amino acid levels, respectively, compared with the germ line encoded antibody, P3, of the Q52 family. Although A strain mice have been reported to have an insertion in BAFF-R, the receptor for BAFF (B cell activation factor from the tumor necrosis factor family), which could explain our results, A.SW mice have no mutations in BAFF-R.

Primary structure of the antigen-binding domains of a human oligodendrocyte-reactive IgM monoclonal antibody derived from a patient with multiple sclerosis

Several murine IgM monoclonal antibodies (mAbs) promoting remyelination in mice were shown to be germline gene-encoded natural autoantibodies that react with oligodendrocytes and intracellular antigens. Here, we show that human oligodendrocyte-reactive IgM mAb DS1F8 derived from a patient with multiple sclerosis targets microtubule-like structures similar to the murine mAbs. Sequencing of the cDNAs of the variable regions revealed that the antigen-binding domains are also encoded by germline genes. These similarities of mAb DS1F8 to the murine mAbs promoting remyelination suggest that this human mAb is a natural autoantibody. This may imply that the engineering of human autoantibodies for therapy of demyelinating diseases is feasible.

Structural analysis of leech galactocerebrosides using 1D and 2D NMR spectroscopy, gas chromatography-mass spectrometry, and FAB mass spectrometry

Cerebrosides were isolated from the leech species, Hirudo medicinalis, and purified to homogeneity by silicic acid chromatography, followed by preparative thin-layer chromatography. Their structure was determined by spectroscopic and chemical methods. 1D and 2D 1H NMR spectroscopy, DQF-COSY and HMQC indicated that the head group consists of a single galactose residue in the beta configuration. The galacto configuration was determined by the characteristic chemical shift, the spin-spin splitting and the multiplicity of the characteristic resonance of its equatorial H-4 proton, as well as by the splittings of the other ring protons. GC, GC-MS and fast-atom-bombardment mass spectrometry studies indicated that C24:0 and C22:0 are the major saturated fatty acid species. Unsaturated fatty acids present were C25:2, C27:2, C27:3, C28:3, C29:3, C30:3, C33:3. GC-MS indicated the presence of hydroxylated C27:2 and one other unidentified hydroxylated fatty acid. The cerebroside contained an unusual polyunsaturated sphingosine analogue, namely 2-amino-1,3-dihydroxydocsatriene.