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C Linington

Publications and source records attributed to C Linington.

At least 19 recordsLinked to original sources
PubMed1995

Protracted, relapsing and demyelinating experimental autoimmune encephalomyelitis in DA rats immunized with syngeneic spinal cord and incomplete Freund's adjuvant.

Experimental autoimmune encephalomyelitis (EAE) is a model for multiple sclerosis (MS). However, MS is a chronic, relapsing and demyelinating disease, whereas EAE in rats is typically a brief and monophasic disorder showing little demyelination. We demonstrate here that DA rats develop severe, protracted and relapsing EAE (SPR-EAE) after a subcutaneous immunization at the tail base with syngeneic spinal cord and incomplete Freund's adjuvant (IFA). The neurological deficits were accompanied by demyelinating inflammatory lesions in the spinal cord, with infiltrating T lymphocytes and perivascular deposition of immunoglobulins and complement. The induction of SPR-EAE was associated with humoral autoreactivity to myelin oligodendrocyte glycoprotein (MOG) and cellular autoreactivity to the rat myelin basic protein (MBP) peptides 69-87 and 87-101. These two peptides, as well as whole rat MBP, were encephalitogenic. In conclusion, we believe that the presently described demyelinating SPR-EAE represents a useful model for MS.

Amino Acid Sequence↗
PubMed1995

The N-terminal domain of the myelin oligodendrocyte glycoprotein (MOG) induces acute demyelinating experimental autoimmune encephalomyelitis in the Lewis rat.

Using a highly purified recombinant protein, mMOG, we demonstrated that autoimmune responses to the N-terminal domain (a.a 1-125) of the myelin oligodendrocyte glycoprotein (MOG) induce an acute demyelinating variant of experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. Immunisation with 100 micrograms of mMOG in adjuvant at the base of the tail induced mild clinical disease in 9 of 11 animals (mean clinical score 1.1). The disease was characterised histopathologically by the presence of inflammation and focal demyelinating lesions in the central nervous system (CNS). Adoptive transfer experiments suggest that this inflammatory demyelinating pathology is mediated by synergy between a weakly encephalitogenic, MOG-specific T cell response and a demyelinating, MOG-specific autoantibody response. Using in vitro selected mMOG-reactive T cell lines, the encephalitogenic T cell response to this domain of MOG was found to recognise two distinct epitopes, MOG1-20 and MOG35-55; whereas ELISA demonstrated that the immunodominant B cell epitope was located within the amino acid sequence MOG1-25. However although active immunisation with synthetic peptides corresponding to the T cell epitopes, MOG1-20 or MOG35-55, induced an inflammatory response in the CNS, this was not associated with demyelination indicating that the demyelinating antibody response recognises other, possibly conformation dependent epitopes. This study unequivocally demonstrates that MOG-specific autoimmune responses are alone sufficient to induce a demyelinating disease of the CNS and supports the proposal that MOG may play an important role in the immunopathogenesis of multiple sclerosis.

Amino Acid Sequence↗
PubMed1995

Antibody facilitation of multiple sclerosis-like lesions in a nonhuman primate.

In the human disease multiple sclerosis (MS), the immune mechanisms responsible for selective destruction of central nervous system myelin are unknown. In the common marmoset Callithrix jacchus, a unique demyelinating form of experimental allergic encephalomyelitis resembling MS can be induced by immunization with whole myelin. Here we show that the MS-like lesion can be reproduced by immunization against the extracellular domain of a single myelin protein, myelin/oligodendrocyte glycoprotein (MOG). By contrast, immunization against the quantitatively major myelin proteins myelin basic protein or proteolipid protein results in inflammation but little or no demyelination. Furthermore, in the presence of encephalitogenic (e.g., disease-inducing) T cells, the fully demyelinated lesion is reconstructed by systemic administration of IgG purified from whole myelin-, or MOG-immunized animals, and equally by a monoclonal antibody against MOG, but not by control IgG. Encephalitogenic T cells may contribute to the MS-like lesion through disruption of the blood-brain barrier that permits access of demyelinating antibody into the nervous system. The identification of MOG as a major target antigen for autoimmune demyelination in a nonhuman primate should facilitate development of specific immunotherapies for human MS.

Animals↗
PubMed1994

Identification of epitopes of myelin oligodendrocyte glycoprotein for the induction of experimental allergic encephalomyelitis in SJL and Biozzi AB/H mice.

A recombinant protein corresponding to the Ig-like domain of myelin oligodendrocyte glycoprotein (MOG) and synthetic 15-mer peptides of the whole MOG molecule with eight amino acid overlaps were screened for their ability to induce experimental allergic encephalomyelitis (EAE) in Biozzi AB/H (H-2dq1) and SJL (H-2S) mice. Clinical and histologic evidence of EAE developed after sensitization with the recombinant MOG protein in both AB/H and SJL mice. In AB/H mice at least three MOG epitopes within residues 1-22, 43-57, and 134-148 induced clinical and histologic EAE, whereas only the sequence 92-106 was encephalitogenic in SJL mice. Histologically, the inflammatory response in the central nervous system consisted of perivascular accumulations of CD5+ T cells and F4/80+ macrophage/microglia cells equally distributed in the brain and spinal cord. The subpial/meningeal infiltration, characteristic of mouse EAE induced with spinal cord homogenate, was only observed in cases of severe clinical disease in SJL mice in which the cellular infiltrates predominated in the spinal cord. In spite of the presence of histologic lesions in AB/H mice immunized with MOG, clinical disease either rapidly resolved or was clinically silent. In contrast to immunization of SJL mice with recombinant MOG, sensitization to MOG 92-106 induced severe clinical paralysis. After recovery these animals relapsed and exhibited demyelinated lesions. This study is the first to describe encephalitogenic epitopes of MOG that induce both clinical and histologic signs of EAE in mice. These and previous findings implicating MOG as a target Ag for Ab-mediated attack in EAE suggest that such autoreactivity to MOG may be significant in the development of human demyelinating diseases such as multiple sclerosis.

Amino Acid Sequence↗
PubMed1994

Experimental autoimmune panencephalitis and uveoretinitis transferred to the Lewis rat by T lymphocytes specific for the S100 beta molecule, a calcium binding protein of astroglia.

The pathogenic potential of autoimmune T cell responses to nonmyelin autoantigens was investigated in the Lewis rat using the astrocyte-derived calcium binding protein S100 beta, as a model nonmyelin autoantigen. The Lewis rat mounts a vigorous RT1B1 (major histocompatibility complex class II) restricted autoimmune response to an immunodominant S100 beta epitope (amino acid residues 76-91). The adoptive transfer of S100 beta-specific T cell lines induced a severe inflammatory response in the nervous system, but only minimal neurological dysfunction in naive syngeneic recipients. The inability of S100 beta-specific T cell transfer to induce severe disease was associated with a decreased recruitment of ED1+ macrophages into the central nervous system (CNS) in comparison with that seen in severe experimental autoimmune encephalomyelitis (EAE) induced by the adoptive transfer of myelin basic protein (MBP)-specific T line cells. Moreover, unlike encephalitogenic MBP-specific T cell lines, S100 beta-specific T cell lines exhibited no cytotoxic activity in vitro. Histopathological analysis also revealed striking differences in the distribution of inflammatory lesions in MBP- and S100 beta-specific T cell-mediated disease. In contrast to the MBP paradigm, S100 beta-specific T cell transfer induces intense inflammation not only in the spinal cord, but throughout the entire CNS and also in the uvea and retina of the eye. In view of the distribution of lesions throughout the grey and white matter of the CNS we propose to term this new model experimental autoimmune panencephalomyelitis (EAP) to differentiate it from EAE. These experiments demonstrate for the first time that nonmyelin CNS autoantigens can initiate a pathogenic autoimmune T cell response, although the nature of the target autoantigen profoundly influences the clinical and histopathological characteristics of the resulting autoimmune disease. This is not simply a consequence of the distribution of the autoantigen, as both MBP and S100 beta are coexpressed in many areas of the CNS, but reflects differences in the capacity of different regions of the CNS to process and present specific autoantigens. This new model of T cell-mediated autoimmune CNS disease exhibits a number of similarities to multiple sclerosis (MS), such as its mild clinical course and the involvement of areas of the brain and eye, which are absent in myelin-mediated models of EAE. Nonmyelin autoantigens may therefore play an unexpectedly important role in the immunopathogenesis of inflammatory diseases of the CNS.

Amino Acid Sequence↗
PubMed1994

Animal models.

Different models of experimental autoimmune encephalomyelitis (EAE) have been successfully applied to investigate and manifold aspects of the autoimmune pathogenesis of multiple sclerosis. Studies using myelin-specific T-cell lines that transfer EAE to naive recipient animals established that only activated lymphocytes are able to cross the endothelial blood-brain barrier and cause autoimmune disease within the local parenchyma. All encephalitogenic T cells are CD4+ Th1-type lymphocytes that recognize autoantigenic peptides in the context of MHC class II molecules. In the case of myelin basic protein (MBP) specific EAE in the Lewis rat, the T-cell response is directed against one strongly dominant peptide epitope. The encephalitogenic T cells preferentially use one particular set of T-cell receptor genes. Although MBP is a strong encephalitogen in many species, a number of other brain protein are now known to induce EAE. These include mainly myelin components (PLP, MAG, and MOG), but also, the astroglial S-100 beta protein. Encephalitogenic T cells produce only inflammatory changes in the central nervous system, without extensive primary demyelination. Destruction of myelin and oligodendrocytes in these models requires additional effector mechanisms such as auto-antibodies binding to myelin surface antigens such as the myelin-oligodendrocyte glycoprotein.

Animals↗
PubMed1994

The B cell repertoire in experimental allergic neuritis involves multiple myelin proteins and GM1.

Experimental allergic neuritis (EAN) is a T cell mediated disease associated with inflammation and demyelination of peripheral nerves. EAN is an experimental model of Guillain-Barré syndrome. The peripheral nerve myelin components P2 and P0 represent major neuritogens, but the diversity and quantity of B cell responses in EAN are unknown. Lewis rats were immunized with bovine peripheral nerve myelin (BPM), and levels of B cells secreting IgM and IgG antibodies to BPM, P2 and P0, the glycolipid GM1 and five peptides of myelin-associated glycoprotein (MAG) were determined. Already on day 7 post-immunization (p.i.), i.e. before the onset of clinical EAN, lymph nodes contained elevated levels of cells secreting IgM antibodies of all specificities examined. Maximum numbers of IgG antibodies secreting cells were generally reached at the height of clinical disease. The numbers of cells secreting IgG antibodies to BPM, P2, P0, GM1 and MAG peptides were also elevated before disease onset, but they were mostly higher than those of IgM antibodies and they reached their maximum only after recovery. The results imply that EAN is associated with strong B cell responses to all myelin antigens under study without restriction to any immunodominant myelin component or MAG peptides.

Amino Acid Sequence↗
PubMed1994

T lymphocyte recognition sites on peripheral nerve myelin P0 protein.

Synthetic peptides corresponding to the extracellular and cytoplasmic domain of bovine (b) or rat (r) peripheral myelin P0 protein were used to establish a total of 50 short-term T cell lines (TCL) from blood of eight healthy subjects. Despite expressing different HLA-DR and HLA-DQ specificities, one or more TCL (range 1-16) specific for peptide bovine P0 19-38 could be isolated from the blood of each donor. Therefore, this peptide covers an immunodominant T cell recognition site in humans. However, when testing seven bP0-19-38-specific TCL derived from blood of two healthy subjects for recognition of the corresponding human P0 sequence, no TCL showed any proliferative response. Bovine P0-19-38 differs in only two amino acid residues from the human peptide. This observation stresses the necessity for using homologous antigens when screening for T cell-mediated autoreactivity to myelin antigens in humans. Unexpectedly, we failed to establish a single P0 peptide-specific TCL from blood of four patients with acute Guillain-Barré syndrome (GBS), in which P0 is considered a putative target autoantigen. As already suggested by others, this could indicate that T cell responses to P0 do not play a pathogenic role in all GBS cases. Alternatively, in these four patients neuritogenic P0-specific T lymphocytes may have been sequestrated to peripheral nerves.

Adult↗
PubMed1993

Production and characterization of monoclonal antibodies to the extracellular domain of P0.

Seven monoclonal antibodies were raised against the immunoglobulin-like extracellular domain of P0 (P0-ED), the major protein of peripheral nervous system myelin. Mice were immunized with purified recombinant rat P0-ED. After fusion, 7 clones (P01-P07) recognizing either recombinant, rat, mouse, or human P0-ED were selected by ELISA and were characterized by Western blot, immunohistochemistry, and a competition assay. Antibodies belonged to the IgG or IgM class, and P04-P07, reacted with P0 in fresh-frozen and paraffin-embedded sections of human or rat peripheral nerve, but not with myelin proteins of the central nervous system of either species. Epitope specificity of the antibodies was determined by a competition enzyme-linked immunosorbent assay (ELISA) and a direct ELISA using short synthetic peptides spanning the entire extracellular domain of P0. These assays showed that P01 and P02 exhibiting the same reaction pattern in Western blot and immunohistochemistry reacted with different distant epitopes of P0. Furthermore, the monoclonal antibodies P05 and P06 recognized 2 different epitopes in close proximity within the neuritogenic extracellular sequence of P0. This panel of monoclonal antibodies, each binding to a different epitope of the extracellular domain of P0, will be useful for in vitro and in vivo studies designed to explore the role of P0 during myelination and in demyelinating diseases of the peripheral nervous system.

Animals↗
PubMed1993

T cells specific for the myelin oligodendrocyte glycoprotein mediate an unusual autoimmune inflammatory response in the central nervous system.

Myelin oligodendrocyte glycoprotein (MOG)-specific T cells mediate an autoimmune inflammatory response in the central nervous system (CNS) that differs radically from conventional models of T cell-mediated experimental allergic encephalomyelitis (EAE). Using synthetic peptides an encephalitogenic T cell epitope of MOG for the Lewis rat was identified within the extracellular IgG V-like domain of the protein, amino acids 44-53 (FSRVVHLYRN). The adoptive transfer of CD4+ T cells specific for this epitope induce an intense, dose-dependent inflammatory response in the CNS of naive syngeneic recipients. However, unlike the inflammatory response induced by myelin basic protein (MBP)-specific T cell lines, inflammation mediated by the MOG peptide-specific T cells failed to induce a gross neurological deficit. This unexpected observation was not due to a reduction in the overall inflammatory response in the CNS, but was specifically associated with a decrease in the extent of parenchymal (as opposed to perivascular) inflammation, a selective decrease in the number of ED1+ macrophages infiltrating the CNS, and a total lack of peripheral nerve inflammation. The decreased recruitment of macrophages into the CNS could not be ascribed to deficiencies in the synthesis of interferon-gamma, tumor necrosis factor-alpha, interleukin (IL)-6 or IL-2 by the T cell line. Moreover, this sub-clinical inflammatory response induced severe blood-brain barrier dysfunction as demonstrated by the induction of severe clinical disease following intravenous injection of a demyelinating MOG-specific monoclonal antibody. The neurological deficit in EAE thus exhibits an unexpected dependence on the identity of the target autoantigen, which determines the extent and nature of the local inflammatory response and ultimately the extent of the neurological deficit.

Amino Acid Sequence↗
PubMed1993

Microglial involvement in experimental autoimmune inflammation of the central and peripheral nervous system.

Microglial cells form a network of potential antigen presenting cells throughout the nervous system. Much progress has recently been made towards a better understanding of their immunological properties. This study examines their activation in 2 models of T cell-mediated autoimmune inflammation of the nervous system, experimental autoimmune encephalomyelitis (EAE) and its peripheral counterpart, experimental autoimmune neuritis (EAN), induced by the transfer of antigen-specific T cell lines. In both models microglial activation occurs at early stages of the disease. Activated microglial cells show an increased expression of MHC class I and II antigens. In EAE ultrastructural analysis revealed that MHC antigen expression is pronounced on perivascular microglial cells, suggesting this cell population may be important for antigen presentation at a site close to the blood-brain barrier. In contrast to EAE, the microglial reaction in EAN occurs at sites remote from the inflammatory response in the peripheral nerve, not only in the spinal cord but also in the terminal projection fields of primary sensory neurons in the lower brainstem. This early microglial activation in EAN suggests that a rapid and remote signaling mechanism can operate following peripheral inflammation. Immuno-electron microscopy revealed that activated microglial cells are also involved in the synaptic deafferentation of spinal cord motoneurons during autoimmune reactions. The rapid involvement of microglial cells in experimental autoimmune inflammation of the nervous system further points to their role as the main intrinsic immuneffector cell population of the central nervous system.

Animals↗
PubMed1993

The demyelinating potential of antibodies to myelin oligodendrocyte glycoprotein is related to their ability to fix complement.

A panel of 13 monoclonal antibodies (mAbs) has been raised to the central nervous system-specific glycoprotein, myelin oligodendrocyte glycoprotein; five of these mAbs recognize a carbohydrate epitope on the molecule. Although all of the mAbs recognized surface epitopes on cultured oligodendrocytes and stained central nervous system tissue sections in a similar manner, marked differences were seen in their ability to induce demyelination in experimental allergic encephalomyelitis in the Lewis rat. This variation in pathogenic potential was not related to the specificity of a given mAb for carbohydrate or peptide epitopes of myelin oligodendrocyte glycoprotein, but correlated with its ability to fix complement.

Animals↗
PubMed1992

Interferon-gamma potentiates antibody-mediated demyelination in vivo.

The pathogenetic events leading to demyelination in experimental allergic encephalomyelitis and in human multiple sclerosis are still unclear. The involvement of anti-myelin antibodies and activated macrophages as effector cells has been postulated. We investigated the synergistic action of the monoclonal antibody 8-18C5 against myelin/oligodendrocyte glycoprotein and recombinant interferon-gamma on demyelination after simultaneous injection into the subarachnoid space of Sprague-Dawley rats. After combined injection of anti-myelin/oligodendrocyte glycoprotein antibody and interferon-gamma, electrophysiological and morphological evidence for demyelination was found. Cervical somatosensory evoked potentials and cervical short-latency somatosensory evoked potentials were significantly delayed, and the demyelinated area in the spinal cord was significantly enlarged when compared to control rats injected with either compound alone. Injection of either an irrelevant antibody and interferon-gamma or of peritoneal macrophages without anti-myelin/oligodendrocyte glycoprotein antibody and interferon-gamma did not induce demyelination. Our data suggest that the deleterious effect of interferon-gamma on multiple sclerosis may be not only due to its effect on antigen presentation but also due to potentiation of demyelination.

Animals↗
PubMed1992

Cell adhesion molecules of the immunoglobulin supergene family as tissue-specific autoantigens: induction of experimental allergic neuritis (EAN) by P0 protein-specific T cell lines.

The P0 glycoprotein is a homophilic cell adhesion molecule of the immunoglobulin supergene family which is responsible for maintaining the structure of compact internodal myelin in the peripheral nervous system (PNS). Utilizing a panel of synthetic P0 peptides two distinct T cell epitopes have been identified that can induce T cell-mediated experimental autoimmune neuritis (EAN) in the Lewis rat. One T cell epitope (amino acid residues 56-71), is located within the extracellular, immunoglobulin-like domain of P0, while the other disease-inducing T cell epitope (residues 180-199) is located within the proteins cytoplasmic carboxyterminal domain. The adoptive transfer of 10(6) CD4+ T line cells specific for either of these peptide antigens induced EAN in syngeneic recipients. However, while the pathogenic response induced by both peptide-specific T cell lines was identical, their epitopes differ markedly in their immunologic properties in vivo. In particular while the response to peptide p180-199 was immunodominant in animals immunized with either purified P0 protein or the native membrane-bound P0 protein in autologous rat peripheral nerve myelin, no response to peptide p56-71 was detected, indicating that this epitope is cryptic. This study provides the first experimental evidence that the immunoglobulin-like domains of members of the immunoglobulin supergene family can function as target autoantigens in T cell-mediated autoimmune disease.

Amino Acid Sequence↗
PubMed1992

Myelin/oligodendrocyte glycoprotein is a unique member of the immunoglobulin superfamily.

Myelin/oligodendrocyte glycoprotein (MOG) is a primary target autoantigen in experimental autoimmune encephalomyelitis, a widely used animal model for autoimmune demyelinating diseases such as multiple sclerosis. We have isolated several rat MOG cDNAs and confirmed their identity by comparison with MOG N-terminal peptide sequence. As expected, MOG mRNA expression is CNS-specific and peaks during active myelination. Our studies show that full length MOG mRNA is approximately 1.6 kb and encodes a signal peptide of 27 amino acids, followed by 218 residues for mature MOG (24,962 MW). A single site for N-glycosylation is found at Asn-31. Rather than the ubiquitous AAUAAA polyadenylation signal, a series of three overlapping, rare poly A signals were identified. The N-terminal half of mature MOG shares 52% identity with bovine butyrophilin, a possible lipid receptor. This same region has 39% identity with chicken B-G antigen, a major histocompatibility complex antigen involved in B cell selection and immune repertoire development. We show that both MOG and butyrophilin, each exhibiting a single Ig-like variable region domain, meet criteria for inclusion in the immunoglobulin superfamily. Moreover, MOG appears to represent a unique member of this superfamily in that it possesses two potential transmembrane domains, in contrast to a single membrane-spanning domain or glycophospholipid anchor found in all other members of Ig superfamily members.

Animals↗
PubMed1992

Molecular mimicry and the autoimmune response to the peripheral nerve myelin P0 glycoprotein.

In the Lewis rat immunisation with the myelin P0 glycoprotein can induce an inflammatory demyelinating disease of the peripheral nervous system, experimental allergic neuritis (EAN), which has many clinical and histopathological parallels with the human disease the Guillain-Barre syndrome. In view of the reported association of GBS with a number of infectious agents we have investigated whether "molecular mimicry" may occur between microbial antigens and the P0 protein that could possibly trigger a similar pathogenic autoimmune response in man. A computer search of the available protein sequence data bases identified several absolute sequence homologies between P0 and viral proteins that involve five or more consecutive amino acid residues. Four of these sequence homologies involved viral pathogens previously associated with the Guillain-Barre syndrome, namely Epstein-Barr virus (EBV), cytomegalovirus (CMV), Varicella zoster virus (VZV) and human immunodeficiency virus I (HIV I). Although, sequence homologies were also found between viral peptides and the neuritogenic determinants of P0, residues 56-71 and 180-199, these homologies proved incapable of eliciting EAN in the Lewis rat. These observations are discussed with reference to the role that molecular mimicry between T cell epitopes on pathogen derived antigens and the P0 protein may play in the pathogenesis of the Guillain-Barre syndrome.

Amino Acid Sequence↗