Neuritis In Lewis Rats Research Articles

Antigen-specific immunosuppression: Nasal tolerance to PO protein peptides for the prevention and treatment of experimental autoimmune neuritis in Lewis rats

Antigen-specific immunosuppression: Nasal tolerance to PO protein peptides for the prevention and treatment of experimental autoimmune neuritis in Lewis rats

Clomipramine and Imipramine Suppress Clinical Signs and T and B Cell Response to Myelin Proteins in Experimental Autoimmune Neuritis in Lewis Rats

5-Hydroxytryptamine (5-HT) reuptake inhibitors of the zimeldine-type have induced polyneuropathies similar to Guillain-Barré syndrome (GBS) in patients with endogenous depression. Some monoamine neurotransmitters have been shown to affect immune reactionsin vivoandin vitroin a concentration-dependent manner. We therefore studied the effect of the monoamine reuptake inhibitory anti-depressants, clomipramine and imipramine on specific immune response and the clinical course of experimental autoimmune neuritis (EAN), the animal model of GBS in humans. Clomipramine and imipramine both suppressed clinical signs of EAN induced by immunization with bovine peripheral nerve myelin (BPM), when given at a dose of 20mg/kg/day intraperitoneally, via osmotic pumps. Clomipramine and imipramine reduced the numbers of Th1 cells secreting IFN-γ in response to the neuritogenic myelin proteins BPM, P0 and P2 among lymph node mononuclear cells (MNC) from rats with EAN. The levels of cells secreting IgG antibodies to BPM, P2 and GM1 in lymph nodes were reduced at the height of EAN in clomipramine and imipramine treated animals. The action of clomipramine and imipramine on induced IFN-γ and anti-myelin antibodies suggests that the mechanism for the suppressive effect of those substances on EAN symptoms may be due to an action on myelin T and B cell autoreactivity. Considering that the main common pharmacological principle of clomipramine and imipramine is to increase the functional activity of the nor-adrenaline (NA) and serotonin (5-HT) of the monoamines, it seems justified to postulate that the actions of clomipramine and imipramine demonstrated in this study to some extent involve NA and/or 5-HT. The immunomodulatory effects of clomipramine and imipramine call for further research on the potential role of drugs acting on the monoamine system in the treatment of autoimmune diseases, and for further studies of immunological mechanisms in the pathogenesis of depressive disorders.

Modulation of experimental autoimmune neuritis in Lewis rats by oral application of myelin antigens

Experimental autoimmune neuritis (EAN) in Lewis rats is a T cell-mediated disease and serves as an animal model of human inflammatory demyelinating neuropathies. EAN can be induced by immunization with complete bovine peripheral nerve myelin (BPM), the myelin protein P2 or its neuritogenic peptide, each emulsified in complete Freund's adjuvant (CFA). The present study evaluates the effect of oral tolerization with BPM or P2 protein on the development of actively induced EAN. Oral administration of BPM strongly suppressed clinical and histological signs of EAN subsequently induced by BPM/CFA, but feeding of P2 protein alone did not affect its course. In contrast, feeding of BPM did not mitigate the course of EAN subsequently induced by immunization with neuritogenic P2 peptide/CFA. Oral therapy with BPM after onset of myelin-induced EAN only slightly ameliorated the further course of disease, but significantly reduced lethality of this severe form of disease. The findings suggest that immunogenicity of the antigens fed determine strength of tolerance, that downregulation of EAN occurs at the site of immunization and not in the nerve, and that active suppression rather than specific anergization is operative in mediating resistance to EAN. However, only partial tolerance to myelin-induced EAN was achieved in naive animals by transfer of spleen/LN cells from rats orally tolerized with BPM. Although methodic factors may have limited the effect of the cells, the result is suggestive of some contribution of anergy to oral tolerance in the present model. Cholera toxin and LPS were identified as oral adjuvants for BPM and prolonged the state of tolerance. However, LPS exhibited proinflammatory properties if EAN was induced early after BPM/LPS-feeding. Thus, oral application of a mixture of myelin components in combination with cholera toxin may be a useful treatment for chronic inflammatory neuropathies considered autoimmune in nature.

T cell antigenic and neuritogenic activity of recombinant human peripheral myelin P2 protein

The major neuritogenic protein of peripheral nerve myelin is the P2 protein. Human P2 is a candidate autoantigen in inflammatory demyelinating diseases of the peripheral nervous system. Since human P2 is not readily available, we produced full-length recombinant human P2 protein (rhP2) in Escherichia coli. RhP2 was recognized by neuritogenic rat T cell lines and induced experimental autoimmune neuritis in Lewis rats. Production of rhP2 allowed the generation of human T cell lines reactive to the autologous protein. Studies of human T cell autoreactivity as well as efforts to use hP2 as a tolerogen will be facilitated by the large-scale expression of rhP2.

Effects of zimeldine and its metabolites, clomipramine, imipramine and maprotiline in experimental allergic neuritis in Lewis rats

The influence of the selective serotonin (5-HT) reuptake inhibiting antidepressant zimeldine and its metabolite norzimeldine was tested on experimental allergic neuritis (EAN) in Lewis rats, which is an animal model of the Guillain-Barré syndrome (GBS) in man. Zimeldine and norzimeldine both suppressed clinical signs of actively induced EAN when given at a dose of 20 mg/kg/day intraperitoneally via osmotic pumps. The effects of zimeldine, its metabolites norzimeldine and CPP 200 as well as of the antidepressants clomipramine, imipramine and maprotiline on in vitro immune response were tested. Thereby we used an immunospot assay for interferon-gamma (IFN-γ) produced by lymph node mononuclear cells (MNC), which reflects number of memory T lymphocytes activated by antigen or lectin, in this experiment bovine peripheral nerve myelin (BPM) and phytohemagglutinin (PHA), respectively. In the IFN-γ secretion assay zimeldine, CPP 200, clomipramine and maprotiline all in a concentration-dependent mode reduced the number of IFN-γ secreting cells while norzimeldine and imipramine did not affect the IFN-γ secretion. In assays for proliferation in response to antigen or lectin, the concentration 10 −4 M was judged toxic for all substances tested, and at concentrations below that all but zimeldine showed a dose-dependent slight reduction of MNC proliferation. The action of several drugs on induced T cell secretion of IFN-γ suggests that the mechanisms for the suppressive effect of zimeldine and norzimeldine on EAN symptoms can be due to an action on myelin T cell autoreactivity. All the monoamine reuptake inhibiting antidepressants tested in this study showed immunomodulatory effects by either a reduction of the number of IFN-γ-secreting cells or the MNC proliferation. These observations call for further studies of immunological mechanisms in the pathogenesis of mental disorders as well as on the potential role of drugs acting on the monoamine systems in the treatment of recognized autoimmune diseases.

Immunosuppressive Effect of FK506 on Experimental Allergic Neuritis in Lewis Rats: Change of T Cell Subsets.

The effect of a new immunosuppressant, FK506, on experimental allergic neuritis (EAN) was examined in Lewis rats. EAN was induced by inoculation with bovine peripheral myelin. The EAN rats were divided into two groups. FK506-treated EAN rats were prophylactically administered FK506 by injection into the peritoneal cavity at a dosage of 5.0 mg/kg/day for 13 days beginning the day after inoculation. The control EAN rats were injected with only saline solution. FK506 prevented the development of EAN, histologically and clinically. In FK506-treated EAN rats, flow cytometric analysis of T cell subsets of the lymph nodes showed a significant decrease in W3/13 positive T cells on the 14th and 21st day and a decrease in W3/25 positive T cells on the 21st day after inoculation when compared with the control EAN rats. The percentage of OX-8 positive T cells were not significantly different between the two groups. Our results suggest that FK506 prevented the development of EAN by decreasing W3/13 and W3/25 positive T cells.

Prednisolone therapy of experimental allergic neuritis in Lewis rats does not induce relapsing or chronic disease

The effects of therapeutic prednisolone treatment on experimental allergic (EAN) in Lewis rats were evaluated in a controlled clinical and electrophysiological study. Since steroid therapy has been suspected to cause relapsing or chronic disease, monitoring was extended over 200 days. Short-term steroid treatment (5 days of 15 mg/kg prednisolone, n = 8) with sudden steroid withdrawal was compared with long-term application (30 days, beginning at 7.5 mg/kg) in descending dosage ( n = 8). The experiment included saline-injected controls ( n = 8) and controls for stress possibly exerted by the handling of the animals. Treatment was begun at the onset of clinical signs. The clinical and electrophysiological data indicated that deterioration, recovery and mild (insignificant) relapse (after 30 and day 108) occurred in all groups at the same time. Both steroid application schemes significantly ( p < 0.03) attenuated the severity and shortened the duration of EAN. Relapse was not aggravated after steroid treatment. The clinical course and electrophysiological findings were unaltered by the experimental procedures and by mild experimental stress.

Lack of effect of fish oil-enriched diet on experimental allergic neuritis in Lewis rats

Lewis rats were maintained on a diet enriched with menhaden oil, a rich source of the arachidonic acid (AA) substitute eicosapentaenoic acid (EPA). After dietary manipulation the blood neutrophils showed normal leukotriene (LT)B 4 but increased LTB 5 concentrations, and the CD4 +/CD8 + T lymphocyte subset ratio was temporarily perturbed. The dietary manipulation did not affect the severity of actively induced experimental allergic neuritis (EAN).

P 0 myelin protein produces experimental allergic neuritis in Lewis rats

P 0 protein was prepared from bovine spinal root myelin. The purity was shown by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunostaíning with affinity purified antisera. P 0 in the presence of lysophosphatidylcholine induced paralysis and histological lesions resembling experimental allergic neuritis in Lewis rats. Lysophosphatidylcholine also enhanced the ability of P 2 to produce neuritis. The conformation of these proteins may be important in determining their ability to induce experimental allergic neuritis. P 0 deserves consideration as an antigen relevant to Guillain-Barré syndrome.

T‐Lymphocyte subsets, functional deficits, and morphology in sciatic nerves during experimental allergic neuritis

Conduction velocities, demyelination, "macrophage/dendritic" cells, different sets of T-lymphocytes, and immunoglobulins were estimated in sciatic nerves during various phases of experimental allergic neuritis in Lewis rats. Demyelination was minimal day 15 postimmunization (p.i.) when conduction velocity already was reduced, somewhat more pronounced day 17 p.i. when nerve conduction was blocked, and most pronounced day 23 p.i. when nerve conduction partially had recovered. This suggests a dissociation between the degree of demyelination and the functional deficits. Decrease of sciatic nerve conduction velocities coincided with endoneurial appearance of T-lymphocytes and "macrophage/dendritic" cells, as well as endoneurial immunoglobulins, day 15 p.i. Later partial functional recovery occurred in parallel with the disappearance of T-cells. The degree of functional deficits thus correlated with the number of endoneurial T-lymphocytes. T-cells may, directly or indirectly, initiate several of the disease components in experimental allergic neuritis, including the nerve conduction deficit.

Dynamics of Ia-expressing cells and T lymphocytes of different subsets during experimental allergic neuritis in Lewis rats

Inflammatory cells were characterized by immunohistochemistry, utilizing monoclonal antibodies against cell surface antigens in frozen sections of sciatic nerves and nerve roots of Lewis rats, sacrificed during the course of experimental allergic neuritis. Large numbers of Ia-expressing irregular macrophage-like/dendritic cells, as well as W 3 13 reactive T lymphocytes of both W 3 25 reactive helper and ox8 reactive suppressor/cytotoxic phenotypes were seen within afflicted peripheral nervous tissue at the start of clinical symptoms and at the height of the disease. T lymphocytes of both helper and suppressor/cytotoxic phenotypes decreased concomitant with clinical recovery. During this period demyelination was still extensive and Ia-expressing macrophage-like/dendritict cells were abundant

Degradation of bovine P2 protein by bovine brain cathepsin D.

Bovine brain cathepsin D cleaved bovine P2 protein to produce three major and several minor peptides. The major P2 peptides formed were shown by amino acid analysis and partial sequencing to be peptides 17-54, 20-58 and 65-131 with the latter predominating. In preliminary experiments, P2 peptide 65-131 did not induce experimental allergic neuritis in Lewis rats in equimolar amounts to the neuritogenic P2.

Circulating lymphocyte subpopulations in experimental allergic neuritis

T-cell subsets in the peripheral blood were analyzed using monoclonal antibodies during the development of experimental allergic neuritis in Lewis rats. Percentages of helper and suppressor cells and ratios of helper/suppressor cells did not exceed normal limits during the development of the disease.

The passive transfer of severe allergic neuritis in Lewis rats with lymphoid cells preincubated with P2 protein

The passive transfer of both clinical signs and histologic lesions characteristic of allergic neuritis was successfully performed in Lewis rats using pooled spleen and lymph node cells, or T lymphocytes therefrom, if first preincubated in petri dishes with P2 protein for 72 hr. For passive transfer, cells were taken from donors 8–16 days after sensitization with P2 protein or myelin in Freund's complete adjuvant, and administered via the tail vein; clinical signs appeared 12–13 days later. This study supports the importance of cell-mediated immunity in EAN and the antigenic role of the P2 protein.

Ia-expressing cells and T lymphocytes of different subsets in peripheral nerve tissue during experimental allergic neuritis in Lewis rats.

Inflammatory infiltrates in sciatic nerves during the acute phase of experimental allergic neuritis in the Lewis rat have been characterized with regard to occurrence and distribution of Ia-expressing cells and T-lymphocyte subsets by the help of an immunohistochemical double-staining technique, enabling the simultaneous visualization of T lymphocytes and Ia-expressing non-T cells. Large numbers of Ia-expressing irregular macrophage-like/dendritic cells were seen both within inflammatory infiltrates and within afflicted nervous tissue. Many W3/13-reactive T lymphocytes of both 'helper' and 'suppressor/cytoxic' phenotypes appeared in close contact with these Ia-expressing non-T cells, particularly within the infiltrates. B lymphocytes and plasma cells were relatively few and mainly found close to endoneurial vessels.

Allergic neuritis: a neuritogenic peptide from the P2 protein that induces disease in rats.

Peptide CN1, a large 93 residue peptide, derived from residues 21-113 of the bovine and rabbit P2 protein of sciatic nerve myelin, induces severe allergic neuritis in Lewis rats. When complexed with phosphatidylserine and tested at 50 microgram dosage in Freund's complete adjuvant, it induces severe clinical and histologic signs (cellular infiltration and demyelination of the sciatic nerve) in most animals. It is as potent in disease induction as the P2 protein on a weight basis. In contrast, when not complexed with phosphatidylserine, Peptide CN1 induced only mild clinical signs and histologic lesions in 3 of 10 rats. CNBr peptides CN2 and CN3, derived from the carboxyl and amino terminal ends, respectively, were not active. Spleen and lymph node cells from rats sensitized to Peptide CN1 responded to both P2 and Peptide CN1 in culture in the mitogenic assay. These data show that the major neuritogenic domain for the rat resides in the CN1 region.

Experimental allergic neuritis in Lewis rats: Altered pattern of disease induced by pertussis vaccine

Experimental allergic neuritis (EAN) was induced in Lewis rats by a single injection of sciatic nerve-complete Freund's adjuvant either with or without a simultaneous injection of pertussis vaccine as a supplemental immunopotentiating agent. Fibrin deposition, documented by immunofluorescence and electron microscopy, was found to be an important immunohistopathologic concomitant of this autoimmune peripheral nervous system disorder irrespective of whether pertussis vaccine was included in the sensitization regimen. In contrast to the well-known capacity of pertussis vaccine to accelerate and intensify other analogous experimental autoallergies, Lewis rats receiving pertussis vaccine in addition to peripheral nerve sensitization clearly developed a less intense form and altered pattern of EAN as manifested by: (a) decreased thoracic cage muscular weakness and associated respiratory impairment and (b) decreased sciatic nerve inflammation. Diminished inflammation of sciatic nerves was accompanied by increased fibrin deposition and focal cellular infiltration within the brain. Pertussis vaccine would appear to exert an immunosuppressive effect on EAN while simultaneously retaining its known capacity to augment immunologic injury of the central nervous system.

Passive transfer of experimental allergic neuritis in Lewis rats by direct injection of sensitized lymphocytes into sciatic nerve.

Lewis rats injected intraneurally with 6×104 to 6×106 lymph node cells from nerve-immunized donors of the same strain showed more intense cellular infiltrates in nerve and more intensive demyelination than did controls given cells from adjuvant-immunized or non-injected control donors. Twenty of twenty-two recipients of cells from nerve-immunized donors showed perivenular round cell infiltrates; only four of thirty-four controls showed comparable infiltrates.