A monoclonal antibody raised to corpus callosum extract reacts with 2',3'-cyclic nucleotide 3'-phosphohydrolase

Monoclonal antibody against 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) was generated by fusing mouse myeloma cells with spleen cells from BALB/c mice immunized with delipidated white matter from rat corpus callosum. The antibody was characterized by solid-phase radioimmunoassay, immunoblot of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoprecipitation from C6 glioma cells, and indirect immunofluorescence staining of monolayer cultures containing oligodendrocytes. The monoclonal antibody bound specifically to an intracellular antigen of oligodendrocytes, but not to Schwann cells, astrocytes, neurons, or fibroblast cytoplasm. The immunoblot of SDS-PAGE of CNS myelin showed that the antibody identified two protein bands at 48,000 and 50,000 molecular weight. These proteins were not identified in peripheral nervous system myelin. The monoclonal antibody immunoprecipitated CNP enzyme activity from extracts of C6 glioma cells. This monoclonal antibody should prove useful in further study of this myelin-specific enzyme in CNS myelin and in cells responsible for myelin production.

Optic nerve demyelination induced by human serum: patients with multiple sclerosis or optic neuritis and normal subjects

We injected guinea pig optic nerves with serum from patients with MS or acute optic neuritis (ON), or normal subjects. Serum from 12 of 17 MS patients, 3 of 3 patients with ON, and 5 of 11 normal age- and sex-matched controls produced myelin vesiculation and demyelination 24 hours after injection. Nerves injected with demyelinating serum contained oligodendrocytes with pyknotic nuclei and edematous, rarefied cytoplasm. Nerves injected with serum that did not cause demyelination did not have these oligodendrocyte changes. Serum from normal subjects or patients with MS may induce in vivo demyelination in mammalian CNS.

Fibroblast growth factor is a mitogen for oligodendrocytes in vitro

The effect of fibroblast growth factor (FGF) on oligodendrocyte development has been studied using dissociated mixed brain cells, cultured in a previously described serum-free medium. A greater number of galactocerebroside-positive oligodendrocytes could be demonstrated after 7 days in the presence of FGF than in control values. Using combined immunofluorescence and autoradiography an increased [3H]thymidine incorporation by galactocerebroside-positive oligodendrocytes was demonstrated after various times of exposure to FGF.

Expression of H-2 antigen on oligodendrocytes is induced by soluble factors from concanavalin A activated T cells

It has been shown that soluble factors from activated T cells, or interferon alone, enhance the expression of major histocompatibility complex (MHC) antigens in several cell types. In this study we have demonstrated, by means of indirect immunofluorescence and radioimmunoassay, that the expression of mouse MHC class I antigen (H-2) on isolated mouse oligodendrocytes is induced by soluble factors from concanavalin A activated T cells. Autoradiographic studies indicate that this induction of H-2 expression is not accompanied by proliferation of oligodendrocytes.

Rat oligodendrocytes have cell adhesion molecules

The aggregation of isolated oligodendrocytes appears to be mediated by cell adhesion molecules. The cell adhesion molecules are inactivated by trypsin. Regeneration of the adhesion molecules is prevented by inhibitors of either protein synthesis or glycosylation. An immunological assay is described to quantitate the molecules involved in oligodendrocyte adhesion based on the following criteria: (a) treatment of oligodendrocytes with rabbit immunoglobulins against oligodendrocyte-conditioned medium prevented their aggregation; and (b) incubation of these immunoglobulins with oligodendrocyte-conditioned medium neutralized their ability to inhibit aggregation.

Requirements for brain cell attachment, survival and growth in serum-free medium: effects of extracellular matrix, epidermal growth factor and fibroblast growth factor

Prolonged survival of dissociated brain cells in serum-free medium has required an incubation in medium containing serum prior to their transfer to serum-free medium. The aim of this study was to eliminate this serum requirement by finding an appropriate substratum for cell survival in a totally serum-free system. Several purified glycoproteins of the extracellular matrix (ECM) and a basal lamina-like ECM produced by corneal endothelial cells were tested for their effect on brain cell attachment and survival. Dissociated brain cells, which had not been exposed to serum, attached well to tissue culture plastic and to the complex ECM (97-98%). Attachment was slightly reduced on fibronectin and type-IV-collagen (90-92%) and inhibited considerably by laminin, type-I-collagen and a surface which had been exposed to serum-containing medium. In each instance, attachment was reduced when cells were seeded in medium containing 2.5% fetal calf serum. The only culture substratum tested which promoted the survival of a mixed population of cells, in the absence of a serum preincubation, was the basal lamina-like ECM. The effect of epidermal growth factor and fibroblast growth factor on cell survival in a serum-free system was investigated. Each hormone stimulated the survival and proliferation of a population of cells which presumably had the appropriate receptors. The relationship between the growth factors and ECM is discussed.

The isolation and long-term culture of oligodendrocytes from newborn mouse brain

Using differential adhesion we successfully isolated relatively pure populations of mouse oligodendrocytes which can be maintained in vitro for more than two months. The highest percentage of galactocerebroside (GalC)-positive oligodendrocytes was 95% at 3 days after isolation. Thereafter, proliferation of astrocytes and fibroblasts occurred more quickly than did oligodendrocyte precursor division. GalC-positive oligodendrocytes rarely incorporate [3H]thymidine so that the use of a mitotic inhibitor (5 X 10(-6)M AraC) reduced the number of non-oligodendrocytes so as to maintain the purity of oligodendrocytes at more than 75% for 14 days in culture. This system will be of use for immunological and virological studies which require viable cultured mouse oligodendrocytes.

Immune responses to myelin antigens in multiple sclerosis

Multiple sclerosis is considered to be a putative immunopathologic disease and there has been considerable effort over the years to prove an autoimmune etiology for it. To date, the evidence is all indirect and there is no proof of either antibody and/or cell-mediated hypersensitivity to any single identifiable CNS constituent whether a constituent of normal CNS or specific to the CNS of MS patients.

The differentiation of oligodendrocytes in a serum-free hormone-supplemented medium

Primary mixed cultures of trypsin-dissociated fetal and newborn rat brain and spinal cord have been grown in a serum-free medium. This medium, containing insulin, selenium, transferrin and triiodothyronine, was optimized for oligodendrocyte survival by determining the number of cells which expressed surface galactocerebroside. Comparison of cultures in serum-containing and serum-free media revealed that galactocerebroside positive (GalC+) oligodendrocytes could be detected earlier in the absence of serum. This early differentiation occurred in the absence of the added hormones and nutrients, whose main function appeared to be to prolong survival of the cells. The effect of serum on the differentiation of oligodendrocytes was studied by comparing the expression of surface GalC in media containing 2.5% or 10% fetal calf serum. At a given time a much greater number of GalC+ oligodendrocytes could be detected at the lower serum concentration. However, when cultures were transferred from 10% serum to serum-free medium (or 1% serum) large numbers of GalC+ oligodendrocytes subsequently appeared, showing that precursors were present in the high-serum medium, but that they were unable to differentiate. Possible explanations of the effect of serum on oligodendrocyte differentiation are discussed.

The mitotic history and radiosensitivity of developing oligodendrocytes in vitro

By use of pulse-chase exposure of dissociated cells of rat fetal spinal cord or brain to [3H]thymidine (TdR) and unlabeled TdR it has been shown that oligodendroglial precursors which do not express galactocerebroside (GalC) divide first and later differentiate to express GalC. The rate of proliferation of more mature GalC+ oligodendrocytes is considerably lower than that of their GalC- precursors. It has been found that oligodendrocyte precursor cells are extremely sensitive to [3H]TdR irradiation. Exposure to as little as 0.03 microCi/ml for 24 hr proved to be harmful, particularly during a critical period before birth. This critical period corresponded to the peak of division of oligodendrocyte precursor cells.

Tissue culture demyelination by normal human serum

Serum from all of 20 normal individuals induced some degree of demyelination when applied to well-myelinated mouse cerebellum cultures. An intact complement sequence through C5 is required. Demyelinating activity was heat labile at 56 degrees C for 30 minutes but was not destroyed at 50 degrees C for 30 minutes (which inhibits properdin factor B and alternate complement pathway activation, but not the classic complement pathway). Sera from patients with agammaglobulinemia, C4 deficiency, or C6 deficiency all induced demyelination. Our results suggest that tissue culture demyelination results from nonimmunoglobulin activation of the alternate complement pathway and is not limited to sera from patients with neurological disease.

Antigalactocerebroside serum demyelinates optic nerve in vivo

Antiserum to the myelin lipid galactocerebroside (GalC) causes rapidly progressive focal demyelination when injected into guinea pig optic nerves. The capacity of anti-GalC to induce central nervous system demyelination is complement-dependent, and demyelinating activity is present in the immunoglobulin fraction of anti-GalC serum. Demyelination appears to result from primary damage to oligodendrocytes.

Generation and biological properties of a monoclonal antibody to galactocerebroside

Galactocerebroside ( GalC ) is a major glycolipid of myelin and myelin-forming cells. We have generated a mouse IgM monoclonal antibody to GalC (M-anti- GalC ) which bound only to oligodendrocytes in rat and bovine central nervous system cultures as assessed by immunofluorescence. Double staining with rabbit anti-glial fibrillary acidic protein and anti-fibronectin antisera revealed no binding of M-anti- GalC to astrocytes or fibroblasts. Schwann cells, but not fibroblasts, were stained in short-term cultures of rat Schwann cells. M-anti- GalC exhibited in vitro cytotoxicity to rat and bovine oligodendrocytes in the presence of complement. This monoclonal antibody with its monospecificity, consistent titer, and capacity to induce cell lysis should be useful for in vitro and in vivo investigations concerning myelination and demyelination.

Human alpha-fetoprotein-rich fraction inhibits galactocerebroside antibody-mediated lysis of oligodendrocytes in vitro

Polyclonal rabbit antiserum to galactocerebroside (anti-GalC) produces titer-dependent lysis of cultured Percoll-isolated bovine and rat oligodendrocytes. In this study anti-GalC produced complement-dependent lysis of 76% of the bovine cells and 65% of the rat cells maintained for 3 to 6 days in vitro. With the concomitant addition of human umbilical cord serum fractions containing fetal alpha-fetoprotein (AFP), lysis was decreased to 31% and 39%, respectively. Control antisera (anti-complete Freund's adjuvant/albumin) showed a cytotoxicity index of 15% for bovine cells and 23% for rat cells. Neither albumin, nor normal human serum, nor any of several pregnancy-associated hormones reduced the lysis produced by anti-GalC. AFP-rich fraction reduced oligodendrocyte lysis when mixed with anti-GalC or complement, but not when first incubated with the cells. Similar findings were obtained when AFP was assayed in specific oligodendrocyte radioimmunoassays utilizing anti-GalC antibody. Our experiments indicate that AFP activity may result from its binding to anti-GalC antibody; it is possible that the Fc portion of the antibody is involved. These data provide in vitro evidence of a possible immunosuppressive role of AFP in the central nervous system.

Cultured human and rat oligodendrocytes and rat Schwann cells do not have immune response gene associated antigen (Ia) on their surface

In order to determine if oligodendrocytes or Schwann cells had surface immune response gene associated antigen (Ia), we studied the binding of: (a) mouse monoclonal antibodies to rat Ia, to cultures of rat oligodendrocytes and Schwann cells; and, (b) mouse monoclonal antibodies to human Ia, to cultures of human oligodendrocytes employing radioimmunoassay and indirect immunofluorescence. Cells were identified using phenotypic markers; rabbit anti-galactocerebroside (GalC) for oligodendrocytes; rabbit anti-GalC and rabbit anti-Schwann cell for Schwann cells; rabbit anti-glial fibrillary acidic protein for astrocytes; rabbit anti-fibronectin for fibro-blasts and leptomeningeal cells, and the capacity to ingest latex particles for macrophage-microglia. Ia could not be detected on the surface of oligodendrocytes, Schwann cells, astrocytes, fibroblasts, or leptomeningeal cells. A small number of latex ingesting cells bound anti-Ia even after blocking of surface Fc receptors.

Long-term culture of human oligodendrocytes. Isolation, growth and identification

Oligodendrocytes were isolated from adult human brains obtained at autopsy. The cells were prepared by Percoll density gradient centrifugation, seeded on plastic coverslips and were cultured for a period up to 6 months. The oligodendrocytes in culture expressed cell-type specific markers, galactocerebroside and myelin basic protein and revealed the ultrastructure of mature oligodendrocytes.

Absence of expression of OKT8 antigen on cultured human, calf and rat oligodendrocytes

Monoclonal antibodies which recognize human suppressor T cells (OKT8) have been reported by Oger and co-workers to bind to cultured sheep oligodendrocytes. These authors speculated that an immune response directed at determinants shared by suppressor lymphocytes and oligodendrocytes could explain the decrease in both circulating blood suppressor T cells and oligodendrocytes in patients with multiple sclerosis. In view of the vital issue of potential cross-reactivity between oligodendrocytes and lymphocytes, we studied the binding of viable cultured calf, rat and human oligodendrocytes using monoclonal antibodies to human T cells and monocytes. We report here that we were unable to confirm the presence of shared determinants among oligodendrocytes and any leukocytes, including human T cells or monocytes. As the reported observations of lymphocyte-oligodendrocyte shared determinants could not be identified in three other species, including man, we found no evidence to support the hypothesis that such shared determinants are of importance in the pathogenesis of multiple sclerosis.

Long-term culture of oligodendrocytes isolated from rat corpus callosum by Percoll density gradient. Lysis by polyclonal antigalactocerebroside serum

Oligodendrocytes isolated from the corpus callosum of four-week-old rats by trypsimization and Percoll density gradient centrifugation were cultured on poly-1-lysine coated coverslips. Some cells extended short processes within 24 hours (h), and at that time up to 95% of the cells showed surface binding of rabbit antiserum to galactocerebroside (anti-GalC) as demonstrated by indirect immunofluorescence. Oligodendrocytes survived up to two months in culture, extending processes with membranous elaborations. Exposure of living oligodendrocytes to varying dilutions of rabbit anti-GalC serum in the presence of complement produced cytotoxicity which was directly proportional to the concentration of antiserum and duration of exposure, as assessed by a nigrosin dye exclusion test. This system of isolating and culturing rat oligodendrocytes will permit further developmental and immunologic studies related to demyelinating diseases.

The ultrastructure of isolated rat oligodendroglial cell cultures

Cultured rat oligodendrocytes were studied by transmission electron microscopy. Cells were identified by an immunocytochemical stain for galactocerebroside, a specific cell surface marker for oligodendroglial cells. Oligodendroglial cell perikarya contained numerous ribosomal rosettes, microtubules, prominent networks of cisternae of the Golgi apparatus and residual bodies. Glycogen and intermediate filaments were absent. Oligodendrocytes gave rise to numerous processes. Pentalaminar and heptalaminar profiles, consistent with tight and gap junctions, were seen between plasma membranes of processes and between perikarya and processes. The cell surface of processes showed numerous gross ruffles which stained for galactocerebroside. Similar membranous profiles appeared in the vicinity of oligodendroglial processes and suggested to us that the plasma membrane of certain of its components may be released into the medium. We concluded that cultured rat oligodendrocytes maintain many similarities with oligodendrocytes in situ and, therefore, are valid models for morphologic, physiologic and biochemical studies.

Acute conduction block associated with experimental antiserum-mediated demyelination of peripheral nerve

Intraneural injection of antisera from rabbits with high antigalactocerebroside antibody levels into rat sciatic nerve produced acute nerve conduction block. This was first apparent in some motor axons between 30 and 60 minutes after injection and progressed to completion within 2 to 4 hours. Concurrent morphological evidence of demyelination was present, but structural changes at the time of onset of block were mild and were restricted to the myelin and Schwann cell, particularly at the paranodal areas and Schmidt-Lanterman clefts. It is suggested that paranodal lesions could account for the observed conduction block.

In vivo demyelinating activity of sera from patients with Guillain-Barré syndrome

The in vivo demyelinating capacity of sera from 27 patients with Guillain-Barré syndrome (GBS) and 47 other individuals was studied by intraneural injection into rat sciatic nerves. The morphological features of the nerves in cross section taken just proximal to the site of needle insertion was assessed 48 hours after injection and the extent of demyelination was quantitated. All 27 GBS serum samples were obtained in the first three weeks of clinical disease. Of these, 11 (41%) produced demyelination. Demyelinative activity of GBS sera correlated only with severity of clinical disease (p less than 0.01). The extent of demyelination after intraneural injection of human sera was less intense on average than that produced by sera from animals with experimental allergic neuritis. Three of 40 (7.5%) sera obtained from normal subjects and patients with other neurological diseases also caused in vivo demyelination, although the activity was weaker and occurred less often than with GBS serum.

Long term culture of bovine oligodendroglia isolated with a Percoll gradient

Oligodendroglia were isolated from calf central nervous system (CNS) white matter by trypsinization in phosphate buffered saline and separation by centrifugation through Percoll. Using antisera to phenotypic markers and double labelling experiments we were able to identify essentially all cells in the cultures. The cells obtained were: (1) viable; (2) had intact plasma membranes and well preserved organelles, ribosomes and mitochondria; and (3) were greater than or equal to 95% oligodendroglia 16-20 h after isolation as determined by ability to bind antigalactocerebroside antibodies (anti-GalC). Oligodendroglia could be cultured for several weeks to months. Oligodendroglia established and maintained processes which bound anti-GalC. Myelin basic protein could be demonstrated in the cytoplasm of 40-60% of oligodendroglia cell bodies but not in the processes.

Radioimmunoassay for detection of anti-oligodendrocyte antibodies

A solid phase radioimmunoassay (RIA) for detection and quantitation of rabbit anti-oligodendrocyte antibody has been developed using bovine oligodendroglia preparation. The assay is simple, rapid, reproducible and economical. It is approximately 150 x as sensitive as immunofluorescence. Specificity has been established by using different bovine tissue antigens as substrate and absorption studies. This assay represents a potentially powerful tool for the detection and quantitation of anti-oligodendroglial antibodies and oligodendroglial antigens in serum and CSF of man and experimental animals.