myelin-oligodendrocyte-glycoprotein-(35-55) and Optic-Neuritis

Optical neuritis (ON) is characterized by inflammation of the optic nerve, and is one of the first clinical signs of multiple sclerosis (MS). Experimental autoimmune encephalomyelitis (EAE) is the animal model used to study MS and ON. The present study evaluated the induction, development and progression of ON using an EAE model induced by 100 μg or 300 μg of MOG35-55. An EAE model was induced in C57BL/6 mice by tail base injection of 100 μg or 300 μg of MOG35-55 in complete Freund's adjuvant, supplemented with Mycobacterium tuberculosis. On the day of injection and 48 h later, animals received intraperitoneally 300 ng of pertussis toxin. On days 7, 10, 14, 21 and 58 the optic nerve was dissected for histological analysis, production of CCL5 and immunohistochemical detection of CD4 and CD8. The histological changes observed in the optic nerves consisted of inflammatory cell infiltrates showing varying degrees of ON in the two groups. The onset of ON in the 300 μg of MOG35-55 group was coincident with higher production of CCL5, on day 10 after induction. However, the 100 μg MOG35-55 group showed more intense inflammatory infiltrate on day 14 after induction, with higher amounts of CD4 and CD8, reaching an excessive demyelination process on days 21 and 58 after induction. The results suggest that two different concentrations of MOG35-55 lead to different forms of evolution of optic neuritis.

Topics: Animals; CD4 Antigens; CD4-Positive T-Lymphocytes; CD8 Antigens; CD8-Positive T-Lymphocytes; Chemokine CCL5; Disease Models, Animal; Dose-Response Relationship, Drug; Encephalomyelitis, Autoimmune, Experimental; Female; Humans; Inflammation; Inflammation Mediators; Mice; Mice, Inbred C57BL; Multiple Sclerosis; Myelin-Oligodendrocyte Glycoprotein; Optic Neuritis; Peptide Fragments

Optic neuritis (ON) is a condition involving primary inflammation, demyelination, and axonal injury in the optic nerve and leads to apoptotic retinal ganglion cell (RGC) death, which contributes to the persistence of visual loss. Currently, ON has no effective treatment. The goal was to determine the effectiveness of immunotherapy with recombinant T-cell receptor ligand (RTL) in preventing ON in humanized HLA-DR2 transgenic mice.. Experimental autoimmune encephalomyelitis (EAE) was induced with myelin oligodendrocyte glycoprotein in humanized HLA-DR2 (DRβ1*1501) transgenic mice. Five consecutive doses of RTL342M were administrated at the onset of ON. The development of autoimmune ON was assessed by histopathology at different time points. The levels of myelin loss, axonal loss, and RGC damage were examined by immunofluorescence.. HLA-DR2 mice developed chronic ON 2 days before EAE characterized by progressive neurodegeneration in both organs. RTL342M significantly suppressed inflammation in the optic nerve and spinal cord and provided protection for at least 30 days. Examination of myelin loss showed a marked suppression of demyelination and an increase in myelin recovery in the optic nerve. Moreover, RTL342M treatment revealed a neuroprotective effect on optic nerve axons and RGCs in retinas at postimmunization (PI) day 62.. RTL342M suppressed clinical and histologic signs of EAE/ON by preventing the recruitment of inflammatory cells into the optic nerve and showed neuroprotective effects against ON. However, to achieve full therapeutic benefit, more doses may be needed. These findings suggest a possible clinical application of this novel class of T-cell-tolerizing drugs for patients with optic neuritis.

Topics: Animals; Axons; Encephalomyelitis, Autoimmune, Experimental; Female; Fluorescent Antibody Technique, Indirect; Glycoproteins; HLA-DRB1 Chains; Immunotherapy; Ligands; Male; Mice; Mice, Transgenic; Myelin Sheath; Myelin-Oligodendrocyte Glycoprotein; Optic Neuritis; Peptide Fragments; Receptors, Antigen, T-Cell; Recombinant Fusion Proteins; Retinal Ganglion Cells; Transgenes

To elucidate the correlation between visual threshold of optokinetic tracking (OKT), visual evoked potential (VEP), and histopathology at different time points after induction of experimental autoimmune optic neuritis (EAON).. EAON was induced in C57BL/6 mice by subcutaneous immunization with an emulsified mixture of myelin oligodendrocyte glycoprotein (MOG)(35-55) peptide. OKT and VEP were measured on days 7, 14, 21, 28, and 42 postimmunization. After VEP measurements, the mice were killed and their eyes were enucleated for histopathological studies. Immunohistochemical staining was performed using cell-specific markers for characterization of cells in the optic nerve: CD3 (T cells), Iba-1 (microglia), MBP (myelin basic protein), and neurofilament (axons).. Functionally, OKT threshold decreased as early as day 7, and VEP latency was significantly prolonged on day 21. Axon degeneration was observed as early as day 14. Activated microglia infiltration was also observed on day 14, before T cell infiltration, which peaked on day 21. Demyelination, confirmed by MBP staining, was observed on day 21.. Microglial infiltration in the optic nerve coincided with decline in OKT threshold and preceded VEP latency prolongation, while VEP latency prolongation coincided with T cell infiltration and demyelination of the optic nerve. These findings may contribute to understanding of the pathophysiology of optic neuritis and future development of more effective therapeutic strategy for refractory optic neuritis.

Topics: Animals; Axons; Calcium-Binding Proteins; CD3 Complex; Evoked Potentials, Visual; Immunoenzyme Techniques; Mice; Mice, Inbred C57BL; Microfilament Proteins; Microglia; Myelin Basic Protein; Myelin-Oligodendrocyte Glycoprotein; Neuritis, Autoimmune, Experimental; Nystagmus, Optokinetic; Optic Nerve; Optic Neuritis; Peptide Fragments; T-Lymphocytes

Autoimmune optic neuritis is a common early manifestation of multiple sclerosis (MS), yet early therapeutic interventions for MS often have high ocular toxicity associated with increased risks for glaucoma, cataract, or retinopathy. This need to discover better early treatment options prompted our development of a sensitive and reliable means to quantify the broad range of pathologies that potentially develop very early in autoimmune optic neuritis. Tissue microfluorimetry was used to measure seven established markers for human MS pathology in normal and autoimmune optic nerves 13 days after antigen exposure, in a Brown Norway rat model of myelin oligodendrocyte glycoprotein (MOG) peptide (35-55)-induced autoimmune optic neuritis. Optic neuritis rats demonstrated early and significant pathologic changes in five established indices for neuroinflammation, immune infiltration, and demyelination that accurately modeled pathologies characteristic of MS. Two indices of MS-like axon damage advanced significantly within 13 days of antigen exposure. Fluorimetrically measured immunoreactivity (-ir) was significantly decreased for paranodin (PN, the requisite axonal paranodal junction protein) and significantly increased for amyloid precursor protein (APP), indicating loss of paranodal junctions and impaired fast axonal transport, respectively. Measurements showing decreased PN-ir with increased APP-ir quantitatively defined a pattern of early axonal damage in autoimmune optic neuritis.

Topics: Amyloid beta-Protein Precursor; Animals; Axons; Cell Adhesion Molecules, Neuronal; Disease Models, Animal; Endothelin-1; Female; Flow Cytometry; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Glycoproteins; Mast Cells; Myelin-Oligodendrocyte Glycoprotein; Optic Neuritis; Peptide Fragments; Rats

Previous strategies to ameliorate experimental autoimmune encephalitis (EAE) include the treatment of autoreactive T cells with altered peptide ligands, which contain amino acid substitutions at TCR contact residues. We recently showed that a variant of myelin oligodendrocyte glycoprotein (MOG) 35-55 possessing low affinity for MHC (45D) induced anergy in MOG 35-55-specific T cells and reduced their encephalitogenicity upon adoptive transfer. Here we investigate the characteristics of the primary immune response to this MHC anchor-substituted peptide. Overall, we observed that immunization with 45D resulted in the production of IFN-gamma and anti-MOG 35-55 autoantibodies at levels similar to those of MOG 35-55-immunized mice with active EAE. However, no symptoms of clinical or histological EAE or overt histological optic neuritis were observed in 45D-immunized mice. Consistent with this finding, 45D-immunized mice did not exhibit CD4(+) infiltrates into the CNS. Therefore, MOG 35-55-specific precursors stimulated with a weak ligand (45D) mediate some EAE-associated effector functions but are unable to fully initiate the inflammatory process in the central nervous system that leads to clinical manifestation of EAE.

Topics: Animals; Autoantibodies; Brain; CD4-Positive T-Lymphocytes; Cell Division; Encephalomyelitis, Autoimmune, Experimental; Enzyme-Linked Immunosorbent Assay; Female; Glycoproteins; Histocompatibility Antigens; Immunoglobulin G; Interferon-gamma; Interleukin-2; Interleukin-4; Mice; Mice, Inbred C57BL; Myelin-Oligodendrocyte Glycoprotein; Optic Neuritis; Peptide Fragments; Peptides; Spinal Cord

The optic nerve is a common site of tissue damage in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). To determine the relationship between optic neuritis (ON) and EAE, we examined the incidence of ON in C57BL/6 (B6) mice immunized with a myelin oligodendrocyte/glycoprotein (MOG)-derived peptide or injected with MOG-specific T cells, which are known to induce EAE.. Mice were immunized with MOG35-55 or MOG40-54 peptides emulsified in complete Freund's adjuvant (CFA). Pertussis toxin (PTX) was injected intraperitoneally 1 day before and after immunization. For disease induction by adoptive transfer of primed cells, donor C57BL/6 mice were received with T-cell blasts (1-6 x 10(6)/mouse). Both EAE and ON were observed by either clinical signs or histology.. ON developed in a high proportion of B6 mice treated with either protocol. The most severe inflammation was observed in the adoptively transferred mice. The induced ON was most frequently bilateral. In either actively or adoptively transferred diseases, both association and dissociation of EAE and ON was observed.. Different MOG-specific T-cell subsets might be involved in the pathogenesis of EAE and ON. A better understanding of the pathogenesis of ON after induction by MOG may have important diagnostic and therapeutic implications.

Topics: Adoptive Transfer; Animals; Encephalomyelitis, Autoimmune, Experimental; Glycoproteins; Immunization; Injections, Intraperitoneal; Mice; Mice, Inbred C57BL; Myelin Proteins; Myelin-Associated Glycoprotein; Myelin-Oligodendrocyte Glycoprotein; Optic Neuritis; Peptide Fragments; T-Lymphocytes