Delayed-type hypersensitivity response in experimental autoimmune neuritis treated with peptide-coupled spleen cells

Experimental autoimmune neuritis (EAN) is a T cell-mediated autoimmune inflammatory disease of the peripheral nervous system that is characterized by demyelination and mononuclear cell infiltration. It is induced in Lewis rats by administration of myelin P2 protein or a synthetic peptide (SP-26) corresponding to amino acid residues 53-78 of bovine P2 protein. Recently, we showed that SP-26, when coupled to syngeneic spleen cells and administered intravenously, provided an effective means of inducing tolerance by inhibiting the clinical signs, decreased proliferative response of lymphoid cells to SP-26 and histological changes of EAN. However, our current data indicate that, despite tolerance induction in these Lewis rats, the antigen-specific delayed-type hypersensitivity (DTH) response to SP-26 remained intact. Furthermore, interferon (IFN)-gamma production by spleen cells of tolerized rats were unchanged as compared to EAN rats. The in vitro proliferation of T lymphocytes from tolerized rats stimulated by SP-26 was reduced as compared to EAN controls but was enhanced upon addition of exogenous interleukin-2. Thus, reduction in EAN clinical signs does not necessarily indicate a decrease in DTH response and IFN-gamma production in EAN Lewis rats. The implication of this finding in regard to immunoregulatory mechanism of DTH response is discussed.

Induction of peripheral tolerance with peptide-specific anergy in experimental autoimmune neuritis

Neuritogenic T cells specific for SP-26, a synthetic peptide (residue 53-78) of myelin P2 protein that causes experimental autoimmune neuritis (EAN), use the same T cell receptor (TCR) V gene family (V beta 8) that can induce experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Tolerance to autoregulatory T cells may be induced in rats by intravenous (iv) administration of antigen-coupled splenocytes; however, the mechanisms that lead to altered immune reactivity are not well understood. Here we demonstrate that SP-26, when coupled to syngeneic spleen cells and administered iv, either before or after disease induction, markedly inhibited development and expression of clinical signs and histological changes of EAN. The induction of tolerance by this method was peptide-specific and MHC-restricted. We showed previously that T cells involved in EAN utilize the T cell antigen receptor V beta 8, whereas less than 5% of normal rat peripheral T cells express V beta 8. We have examined T lymphocytes from tolerized rats to determine the presence or absence of V beta 8(+)-bearing cells in order to determine the mechanism of tolerance. V beta 8 cells were undetectable by Northern blot analysis in the lymph nodes of unimmunized animals but easily detected in SP-26-primed and tolerized rats. In addition, spleen cells isolated from tolerized animals were anergic and failed to proliferate in response to SP-26, but retained responsiveness to IL-2 and Con A stimulation. Thus, the peptide-specific unresponsiveness that can be induced in rats with EAN, a T-cell-mediated process that is MHC-restricted and utilizes the T cell receptor V beta 8, occurs while V beta 8 transcripts remain readily detectable in spleen and lymph node cells. The detection of V beta 8-bearing T cells requires the development of antibodies specific for this rat surface protein.

Magnetic resonance imaging of the cauda equina in chronic inflammatory demyelinating polyneuropathy

We report a patient with biopsy proven chronic inflammatory demyelinating polyneuropathy whose magnetic resonance imaging demonstrated abnormal enhancement of the cauda equina after administration of gadolinium. Enhancement may reflect alteration of the blood-nerve barrier secondary to inflammation. Magnetic resonance imaging of the cauda equina could be a useful adjunct in the early diagnosis of chronic inflammatory demyelinating polyneuropathy.

Extended survival and function of peripheral nerve allografts after cessation of long-term cyclosporin administration in rats

To determine whether survival and function of peripheral nerve allografts are possible after cessation of long-term cyclosporin (CsA) treatment, we grafted 4.25 cm Lewis rat peripheral nerve allografts (n = 22) into tibial nerve gaps in recipient brown Norway rats. Allograft groups received CsA (15 mg/kg) subcutaneously every day for 20 days and then biweekly for either 5 or 8 months after transplantation. The control group, brown Norway rats with isografts from brown Norway donor rats (n = 2), also received identical CsA treatment. Semimonthly electrophysiologic studies were done from postoperative week 13 until the animals were killed (up to 79 weeks). The corresponding CsA levels in the nerve and blood were recorded from cessation of CsA up to 58 weeks after surgery. No electrophysiologic signs of rejection were observed in any of the 22 allograft recipients treated with CsA for up to 8 months or in 17 of the 22 observed for up to 58 weeks after cessation of CsA. Overall, 5 of 22 allografts were rejected in the first 8 weeks after discontinuation of CsA. Signs of rejection occurred only in the 5-month treatment group and followed the large initial drop in CsA blood level (from 1010 ng/ml to < 25 ng/ml) that occurred within the first 6 weeks after CsA cessation. The two isograft controls demonstrated no electrophysiologic signs of rejection up to 58 weeks after surgery. Peripheral nerve allografts in the rat can regenerate and function on long-term CsA; after cessation of CsA, they can function for extended periods of time without signs of rejection if trace amounts of CsA are present.(ABSTRACT TRUNCATED AT 250 WORDS)

Peripheral nervous system (PNS) expression of mRNAs encoding myelin proteins and Fc gamma RIII during experimental allergic neuritis

Experimental allergic neuritis (EAN) was induced in Lewis rats by injection of 'SP26', a peptide homologous to amino acids 53-78 of bovine myelin P2 protein, in complete Freund's adjuvant. The rats developed signs of EAN which began on day 14, were maximal on day 18, and had subsided by day 30. RNA content of cauda equina and sciatic nerves increased more than 2-fold at the height of EAN. Expression of myelin P0 and P1 mRNAs did not fall during EAN, nor rise during recovery. Fc gamma R mRNA, which encodes Fc gamma RIII, an immunoglobulin-binding protein mediating activation of natural killer cells and macrophages by immune complexes, was transiently, but markedly induced in scattered endoneural cells, presumably macrophages, in cauda equina and sciatic nerves during the period of increasing weakness.

Isolation and characterization of macrophages from rat embryonic muscle culture

We have previously described the wide distribution of resident macrophages in normal rat skeletal muscle. In this study, we investigated the characteristics of the macrophages that occur in rat embryo muscle cultures. We showed that cells of monocyte-macrophage lineage are present in primary muscle cultures of rat embryos (18 days in gestation) and that these cells form morphologically and phenotypically heterogeneous populations, based on their reaction with monoclonal antibodies ED1, ED2, ED3, and OX43. Constitutively Ia+ cells with dendritic appearance were also observed. Furthermore, we established the procedure for isolation of macrophages from the primary muscle cultures. The isolated cells, mostly ED1+, expressed class I and CD4 antigens and bore complement (C3) receptors on their surfaces. The fact that cell of monocyte-macrophage lineage occur in the embryonic muscle suggests that during embryogenesis these cells may enter the developing muscle and give rise to a population of tissue-associated macrophages.

Shared T-cell receptor gene usage in experimental allergic neuritis and encephalomyelitis

Experimental allergic neuritis, an autoimmune disease of the peripheral nervous system, is a model for human Guillain-Barré syndrome. Experimental allergic neuritis is mediated by CD4+ T cells reactive with myelin P2 protein. We demonstrate that these T cells use the same members of T-cell receptor V gene families for both their alpha (V alpha 2) and beta (V beta 8) chains as T cells that cause experimental allergic encephalomyelitis, an autoimmune disease of the central nervous system. Furthermore, these T cells appear to be idiotypically related. Therefore, completely different T-cell lines with different antigen specificities, producing entirely different diseases, share common T-cell receptors.

Evolution of the cellular response in P2-induced experimental allergic neuritis

We examined the development of the inflammatory cellular response and demyelination in P2 protein-induced experimental allergic neuritis (EAN). Collections of inflammatory cells were first identified in nerve roots 14 days after immunization. Ia+ cells predominated in the evolving lesions and T-helper cells were the dominant T-cell type with T-suppressor/cytotoxic cells appearing later in the course of the disease. Vesiculation, the earliest change seen in the myelin sheath, appeared before the wave of cellular infiltration. These results indicate that myelin injury precedes inflammation in P2 protein-induced EAN, and provide further evidence that this disorder is indistinguishable from EAN induced with whole peripheral nerve myelin.

Peptide 53-78 of myelin P2 protein is a T cell epitope for the induction of experimental autoimmune neuritis

We have recently described the clinical and pathological features of experimental autoimmune neuritis (EAN) in Lewis rats inoculated with varying doses of a synthetic peptide corresponding to the amino acid residues 53-78 of bovine P2 protein (SP-26). Immunization with this synthetic peptide was able to induce severe clinical and pathological characteristics of EAN. We are now reporting that, SP-26 T cell lines derived from spleen and lymph node cell populations of such immunized rats, upon being triggered by SP-26, can adoptively transfer severe clinical and histological signs of EAN to naive syngeneic recipients. The disease appears 7-8 days postinoculation of the cells and persist 5-10 days. The pathological features were indistinguishable from SP-26-induced active EAN which appears 12-15 days after sensitization. Examination of the surface phenotype of the cells that were used for the passive transfer of EAN by FACS analysis, showed majority of the cells to be CD4+, Ia+ cells.

Induction of severe experimental autoimmune neuritis with a synthetic peptide corresponding to the 53-78 amino acid sequence of the myelin P2 protein

We generated a synthetic peptide (SP-26), corresponding to the amino acid residues 53-78 of bovine P2 protein, which induced severe clinical and pathological characteristics of experimental autoimmune neuritis (EAN) in Lewis rats. Lymph node cell populations from SP-26-immunized rats elicited a proliferative response to the peptide and to the P2 protein. After 16 cycles of antigen stimulation with the peptide, the SP-26 T cell line shows a decreased response to P2, but not to SP-26. Fluorescence-activated cell sorter (FACS) analysis of a SP-26 T cell line indicated the majority of cells to be of CD4+ CD8-. This report demonstrates that the synthetic peptide SP-26 can induce severe EAN in Lewis rats in a dose-dependent manner. Furthermore, specific T cell lines reactive to SP-26 can be generated from the lymph nodes of SP-26-immunized rats.

Expression of major histocompatibility complex antigens on inflammatory peripheral nerve lesions

The expression of major histocompatibility complex (MHC) antigens by cells of the rat peripheral nervous system (PNS) was studied using a model of peripheral nerve transplantation. Monoclonal antibodies to polymorphic determinants of MHC class I and class II (Ia) molecules were used to determine donor or recipient origin of MHC antigen-bearing cells in nerve allografts. The expression of class I and class II antigens by PNS parenchymal cells was modified during varying alloimmune conditions. Baseline, constitutive expression of class I antigens on endothelial and perivascular cells and class II antigens on interstitial cells were identified. Decreased MHC antigen expression was noted following in vitro culture of nerve allografts prior to implantation. After transplantation, enhanced donor-derived MHC antigen expression was demonstrated by both cultured and untreated allograft endothelial, perivascular and interstitial cells in a pattern which was distinct from isografts. This data supports a concept of perivascular monocytic and/or parenchymal cell (Schwann cell or resident macrophage-like cell) activity as the resident antigen-presenting cell for PNS immune processes.

Perivascular location and phenotypic heterogeneity of microglial cells in the rat brain

Employing immunohistochemical techniques and a panel of monoclonal antibodies that recognize rat cells of monocyte/macrophage lineage, we have demonstrated that cells labeled with these antibodies are widely distributed throughout the parenchyma of the rat brain. These cells have a remarkable microglial morphology and form phenotypically heterogenous populations. Double immunoperoxidase staining with the monoclonal antibody and anti-von Willebrand factor antiserum, which recognizes vascular endothelial cells, revealed that these cells are located exclusively at perivascular sites in the adult brain. These observations indicate that the microglial cells are perivascular cells of the monocyte/macrophage lineage, and may be intimately involved in various immunopathogenic conditions of the central nervous system.

Early myelin lesions in experimental allergic neuritis

We examined the evolution of demyelination in spinal roots of Lewis rats immunized with whole nerve and complete Freund's adjuvant. Roots were morphologically normal until 11 days after immunization, when we found endoneurial edema and myelin vesiculation in the absence of mononuclear cell contacts. Macrophage-associated myelin stripping was not detected until day 12. Macrophage infiltrations were extensive by day 14, but lymphocytes were sparse. These observations indicate that in experimental allergic neuritis, myelin injury may occur before macrophage-mediated demyelination, and provide support for an early role of serum factors in the development of this disorder.

Demonstration and phenotypic characterization of resident macrophages in rat skeletal muscle

Using immunohistochemical techniques and a panel of murine monoclonal antibodies that recognize rat cells of the mononuclear/phagocyte lineage, it has been demonstrated that the cells labelled with these antibodies are widely distributed throughout the perimysial and endomysial sites in the rat skeletal muscle. These cells have a distinctive dendritic morphology and form phenotypically heterogenous populations. Double immunoperoxidase staining with the monoclonal antibody and anti-Von Willebrand factor antiserum, which recognize vascular endothelial cells, revealed that most of these resident macrophages are closely associated with microvasculature. The perivascular location of these cells suggests that at least some of the resident macrophages may be pericytes. These observations indicate that the macrophages form an important component of the non-muscle cell population in the muscle tissue, and may be intimately involved in various immunopathological conditions of the skeletal muscle.

Effect of experimental allergic neuritis serum on normal rat peripheral nerve

To study the possible in vivo activity of experimental allergic neuritis (EAN) serum, we injected serum from rats immunized with whole nerve, P2 protein or adjuvant alone into the sciatic nerve of normal Lewis rats. Serum from whole nerve and P2-immunized animals produced demyelination 24 h after injection. Only high-titer anti-P2 serum was active and no control serum had this effect. Anti-P2 antibodies or other serum factors may contribute to the pathogenesis of whole nerve and P2-induced EAN.

Expression of major histocompatibility complex class I antigens in rat muscle cultures: the possible developmental role in myogenesis

The expression of major histocompatibility complex class I antigens was demonstrated on aneurally cultured rat muscle cells. Myoblasts showed constitutive expression of class I antigens on their cell surfaces. The presence of the antigens was transitory, disappearing as myoblasts fused and differentiated into multinucleate myotubes. Furthermore, antibody against rat class I antigens showed an inhibitory effect on the generation of myotubes during muscle development. Although mature myotubes did not show any detectable levels of class I antigens on their cell surface, soluble factors from concanavalin A-activated spleen cells or interferon gamma could induce the expression of class I antigens on muscle fibers. These results suggest that the expression of class I antigens on muscle cells is not only immunologically modulated but also developmentally regulated and that the antigens may play a role in cell recognition and interactions during the fusion process of myogenesis.

Evolution of the responses to exercise in left ventricular aneurysms after anterior wall acute myocardial infarction

The evolution of the heart rate, blood pressure and electrocardiographic responses to exercise in 20 patients (group A) who exhibited echocardiographic evidence of left ventricular (LV) aneurysms after acute myocardial infarction (AMI) were examined. The responses were compared with those seen in 19 patients without LV aneurysms who were matched for age, gender and location of infarct (group B). Patients taking beta blockers were excluded from the study. It was found that the heart rate response to exercise was accentuated in group A at the time of discharge from hospital and that it became attenuated over 9 to 12 months. The blood pressure response was significantly increased over 9 to 12 months in group B. Persistence of ST elevation during exercise, 10 to 12 weeks after AMI, was diagnostic of an LV aneurysm. One year after AMI the sensitivity of ST elevation was 90%, specificity was 95% and the negative predictive value 90%.

Expression of nerve growth factor receptor during human peripheral nerve development

The expression of NGF receptors on human Schwann cells during development and myelination and in culture was analyzed using a murine monoclonal antibody to human NGF receptor. Nonmyelinated femoral nerves from 13- to 14-week fetuses stained strongly for NGF receptor, whereas tissues from later stages of development showed a decrease in the staining intensity. These changes correlated with the initiation of myelination (17-19 weeks), as observed by phase-contrast and electron microscopy, and the reactivity with monoclonal antibody 4C5, a marker of mature Schwann cells. In adult nerves, only the perineurium and few endoneurial cells were stained with anti-NGF receptor antibody. Cultured human fetal Schwann cells were positive for NGF receptor by immunofluorescence irregardless of donor age or length of time in culture. The decreased staining of NGF receptor with nerve maturation may reflect a dependence of antigen expression on Schwann cell differentiation and/or neuron-Schwann cell interaction.

A monoclonal antibody to Schwann cell surface membrane recognizes a cAMP inducible epitope

A monoclonal antibody to the surface membrane of rat Schwann cells was generated. This antibody bound to Schwann cell surface but not to fibroblasts in mixed neonatal sciatic nerve cultures. It did not bind to cells in newborn rat brain or corpus callosum cultures that contained oligodendrocytes, astrocytes, fibroblasts and neurons. The target antigen for this monoclonal antibody disappeared from Schwann cell surface after 5 days in culture. At this time, addition of 10(-3) M 8-bromo cyclic AMP or 10(-3) M dibutyryl cyclic AMP resulted in the reappearance within 2 days, of the target antigen on Schwann cell surface membrane. The reappearance of this epitope parallels that of surface galactocerebroside on Schwann cells when incubated with cAMP analogues. Re-expression of the target antigen for this monoclonal antibody in the presence of cAMP is evidence that cAMP may be a signal for synthesis of a variety of myelin molecules and as such could be a signal for myelination of axons by Schwann cells.

Astrocytes, oligodendrocytes, and Schwann cells share a common antigenic determinant that cross-reacts with myelin basic protein: identification with monoclonal antibody

We have produced a monoclonal antibody against myelin basic protein that reacts with astrocytes, oligodendrocytes, and Schwann cells. This antibody was generated by fusion of mouse myeloma cells with spleen cells from BALB/c mice immunized with delipidated white matter from adult rat corpus callosum. The antibody was characterized via solid-phase radioimmunoassay, immunoblot of SDS-PAGE, and by indirect immunofluorescence staining of monolayer cultures containing oligodendrocytes, astrocytes, and Schwann cells. Myelin basic protein (MBP) was shown previously to be present only in myelin producing cells in CNS and PNS (oligodendroglia and Schwann cells) and not in astrocytes. The binding of this monoclonal antibody to all 3 cell types suggests that these cells share a common epitope. This epitope may be related to a common progenitor cell.

Isolation of P2 protein--reactive T-cell lines from human blood

Human T-cell lines reactive with the peripheral nerve myelin protein, P2 protein, were isolated from the peripheral blood of 4 normal persons and 1 patient with Guillain-Barré syndrome. These predominantly helper phenotype T-cell lines were isolated and maintained in vitro by antigen stimulation followed by culture with interleukin 2. Myelin basic protein-reactive T cells were also isolated in parallel from the same subjects as antigen specificity controls. T cells recognizing myelin basic protein did not respond to P2 protein, nor did P2-reactive cells respond to myelin basic protein. These findings suggest that a potential for autoimmune reactivity with peripheral nervous system myelin antigens may exist for both normal persons and some patients with neurological disease.

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.

Transfer of experimental allergic neuritis with P2-reactive T-cell lines

Experimental allergic neuritis (EAN) was induced in normal Lewis rats by systemic passive transfer of T-cell lines responding to P2 protein. These cells had predominantly helper phenotype and could induce EAN within 7 days following adoptive transfer. There was no anti-P2 antibody response in the recipients of the P2-reactive cells recovered from donors with high anti-P2 antibody levels. This study provides direct evidence that T cells are important for the induction of EAN. Furthermore, there was no evidence of a pathogenic role for anti-P2 antibody in passive EAN.

The role of myelin P2 protein in the production of experimental allergic neuritis

Myelin P2 protein has been proposed as the primary antigen in whole myelin-induced experimental allergic neuritis (EAN). We investigated the neuritogenic properties of P2 by sensitizing Lewis rats with complete Freund's adjuvant (CFA) containing P2, P2 plus phosphatidyl serine, or whole myelin containing an equivalent amount of P2. Animals were examined using a battery of clinical, electrophysiological, immunological, and morphological methods. Myelin-immunized rats developed the characteristic features of EAN. P2-sensitized rats developed a similar but much less intense disorder. When rats were sensitized with P2 in the presence of phosphatidyl serine, however, they developed radiculoneuropathy that was indistinguishable from myelin-induced EAN. Inoculation with phosphatidyl serine plus complete Freund's adjuvant or complete Freund's adjuvant alone had no detectable effect on peripheral nerves. These studies demonstrate that sensitization of rats with a single myelin antigen, P2 protein, is sufficient to induce the clinical, electrophysiological, and neuropathological features of EAN.

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.

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.

Immune reactions to P2 protein in human inflammatory demyelinative neuropathies

The significance of immune reactions against peripheral nervous system antigens in the human inflammatory polyneuropathies is still uncertain. Using a very sensitive assay, we found greatly increased levels of anti-P2 antibodies in sera of animals with experimental allergic neuritis (EAN) but no increases in humans with acute Guillain-Barré syndrome (GBS), chronic relapsing polyneuritis (CRIP), axonal neuropathy, or normals. P2 protein and CNS basic protein did not induce any increased proliferation in lymphocytes of GBS or CRIP patients. We conclude that P2 and BP appear unlikely to be targets for humoral or cellular immune reactivity in GBS or CRIP.

Antibodies to P2 and P1 myelin antigens in experimental allergic neuritis and allergic encephalomyelitis

We confirmed earlier observations that experimental allergic neuritis (EAN) in Lewis rats induced by injection of bovine peripheral nerve myelin in complete Freund's adjuvant is not accompanied by development of experimental allergic encephalomyelitis. However, sera of these animals contained elevated titers of antibodies against central nervous system myelin basic protein (BP), likely induced by peripheral nerve P1 protein. Anti-BP antibodies were not seen in sera of rats with EAN induced by peripheral nerve P2 protein. Lack of encephalogenicity of bovine myelin in Lewis rats does not reflect simply lack of immune responses induced against BP.

Oligoclonal IgG in the cerebrospinal fluid of guinea pigs with acute experimental allergic encephalomyelitis

The cerebrospinal fluid (CSF) of guniea pigs with experimental allergic encephalomyelitis was examined for the presence of oligoclonal IgG using polyacrylamide gel electrophoresis. Oligoclonal IgG (greater than or equal to 2 bands) was seen in the CSF obtained from 3/4 animals with experimental allergic encephalomyelitis induced by myelin basic protein and 2/3 with spinal cord-induced disease. It was not seen in CSF of 3 non-sensitized, 4 adjuvant-sensitized and 7 liver-sensitized guinea pigs. Scanning of stained gels confirmed the oligoclonal pattern. The bands were found in the region of gels which bound [125I]Staphylococcal Protein A. The data demonstrate that a non-infectious inflammatory reaction within the central nervous system can result in an oligoclonal IgG pattern in the CSF.

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.

Respiration in conscious dogs at rest and during exercise

25 mongrel dogs (average b.w. 24.6 kg) were studied on several occasions at rest and during treadmill exercise of up to 10 mph (15% incline). Minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), tidal volume (VT) and respiratory frequency (f) were determined at rest and at each level of exercise. Individual variability in resting VO2 was considerable (71--695 ml/min). Most often the dogs panted, with VE's above 25 liters/min and f's above 100 min-1. The averate VE/VO2 was 109 at rest. VO2 was linearly related to VE (VO2 = 9.17 VE + 66.9; r = 0.80). Differences in resting VE were largely due to differences in f (f = 3.57 VE + 21.2; r = 0.82). Considerable individual variability in VO2 for a given work load was also observed during exercise. Some dogs showed significant differences in VO2 from experiment to experiment while running at a given treadmill speed. These differences were largely related to the levels of VE. VE/VO2 decreased to 50. We found a leveling off of VO2 (at about 60 ml/min/kg) at treadmill speeds of 5 mph, suggesting that the maximal VO2 in dogs is less than previously reported.

Effects of simulated altitude on O2 transport in dogs

The effects of exposure to simulated altitude on skeletal muscle and on the cardiocirculatory system rhave been studied on awake, conscious, dogs (16-39 kg) at rest and during moderate treadmill exercise at 15% incline. Measurements were obtained in Denver at a PB of 635 mm Hg and after 3 weeks of continuous exposure to a PB of 435 mm Hg using a hypobaric chamber. At both levels of PB the dogs showed marked panting, associated with pulmonary hyperventilation and low PaCO2's (28 mm Hg at 635 and 17 mm Hg at 435 mm Hg). Resting VO2's were high (12.4 and 11.4 ml/min-kg) reflecting the high respiratory outputs. [Hb] and Hct increased significantly after 3 weeks at 435 mm Hg with a 4 mm Hg decrease in P50. Q, HR, SV and systemic blood pressures were normal in both normoxic and hypoxic animals, at rest as well as during exercise. Arterial and mixed venous PO2's decreased in the hypoxic dogs (82 to 56 and 42 to 36 mm Hg, respectively) but arterial O2 content, arterial-venous O2 content difference and systemic O2 transport remained unchanged. Capillary density in the sternothyroid muscle doubled (617 to 1245 cap/mm2) after 3 weeks at a PB of 435, whereas the average muscle fiber diameter decreased about 30%. Calculations indicate that the PO2 in the 'lethal corner' of the muscle fiber is relatively higher in the hypoxic animal because of the decrease in fiber size and intercapillary distances.