Bovine Peripheral Nerve Research Articles

A hereditary disposition for bovine peripheral nerve sheath tumors in Danish Holstein cattle.

BackgroundPeripheral nerve sheath tumors (PNSTs) are frequently found in Danish cattle at slaughter. Bovine PNSTs share several gross and histopathological characteristics with the PNSTs in humans with heritable neurofibromatosis syndromes. The aim of the present study was to investigate a possible hereditary disposition to PNSTs in dairy cattle by statistical analysis performed on data from 567 cattle with PNSTs. Furthermore, a preliminary genome-wide association study (GWAS) was performed on DNA isolated from 28 affected and 28 non-affected Holstein cows to identify loci in the bovine genome involved in the development of PNSTs.ResultsPNSTs were significantly more common in the Danish Holstein breed than in other breeds with 0.49% of Danish Holsteins slaughtered during an eight-year-period having PNSTs. PNSTs also occurred significantly more frequently in the offspring of some specific Holstein sires. Examination of three generation pedigrees showed that these sires were genetically related through a widely used US Holstein sire. The PNSTs included in GWAS were histologically classified as neurofibroma-schwannoma (43%), schwannoma (36%) and neurofibroma (21%) and derived from Holstein cows with multiple PNSTs. A single SNP on chromosome 27 reached genome-wide significance.ConclusionsGross and histological characteristics of bovine PNSTs are comparable to PNSTs in humans (schwannomatosis). Danish Holsteins are genetically disposed to develop PNSTs but the examined materials are insufficient to allow determination of the mode of inheritance.

Morphologic Evaluation of the Ageing Process in Bovine Peripheral Nerves

Morphologic Evaluation of the Ageing Process in Bovine Peripheral Nerves

Isolation, Purification and Verification of Peripheral Nerve Myelin Derived from Bovine Cauda Equina

Background: Animal models of peripheral neuroinflammation are essential to understanding the pathogenesis of, and deducing new treatments for demyelinating polyneuropathies. This paper updates and describes adapted methods for the isolation, purification and verification of bovine peripheral nerve myelin used to reliably induce peripheral neuritis in susceptible mice. Methods: Myelin was isolated via discontinuous sucrose and continuous cesium chloride density gradient ultracentrifugation from frozen adult bovine cauda equina. Negatively stained electron microscopy was employed to confirm myelin structure. Phase contrast and routine light microscopy, gravimetric analyses, gel electrophoresis and lens culinaris fluorescent western blotting, analytical colorimetric assays and indirect immunohistochemistry were performed to analyze whole myelin or its protein and lipid subcomponents. Myelin isolates were used to induce experimental autoimmune neuritis in 8-12 Weeks old female Swedish Jim Lambert/ Jackson mice. Results: Negatively-stained electron microscopy demonstrated the two-dimensional repetitive lamella structure of myelin and a lack of organelle contamination. Lipids accounted for ~72% of the dry mass of bovine peripheral nerve myelin, while ~25% was protein/ proteolipid and <4% insoluble residue based on gravimetric analyses. Glycoproteins accounted for the majority of isolated myelin proteins, with myelin protein zero (~28 KDa) being the most prevalent protein. Phospholipids accounted for ~60% of the total dry weight of bovine peripheral nerve myelin. Surface expression of galactocerebroside and sulfatide, two major lipid subcomponents present in myelin, was detected by indirect fluorescent immunohistochemistry. Bovine peripheral nerve myelin reliably induced a severe macrophagepredominant demyelinating polyneuropathy with associated axonal loss in female mice, consistent with experimental autoimmune neuritis. Conclusions: These updated and adapted methods using readily available resources can be applied to rapidly isolate, purify and verify peripheral nerve myelin from animal sources, and determine its protein and lipid composition prior to use in peripheral neuritis animal models.

Immunohistochemistry for 2′,3′-Cyclic Nucleotide-3′-Phosphohydrolase in 63 Bovine Peripheral Nerve Sheath Tumors

To establish a simple and uniform classification of bovine peripheral nerve sheath tumors (PNSTs), 63 tumors from 44 cattle were examined histologically and immunohistochemically with antibodies against S100 protein and 2',3'-cyclic nucleotide-3'-phosphohydrolase (CNPase). Immunohistochemically, all the tumors were positive for S100 protein, CNPase, or both. Four types of PNST were recognized: 35 schwannomas, 9 neurofibromas, 14 hybrid (neurofibroma-schwannoma) tumors, and 5 malignant PNSTs. Axons were identified by immunohistochemistry for neurofilament in a proportion of tumors of each type of PNST. In conclusion, bovine PNSTs commonly have both schwannomatous and neurofibromatous areas. Moreover, the Schwann cell markers S100 protein and CNPase, in combination with antibodies against neurofilament, are valuable diagnostic tools to classify bovine PNSTs.

Membrane attack complex of complement is not essential for immune mediated demyelination in experimental autoimmune neuritis

Antibody deposition and complement activation, especially membrane attack complex (MAC) formation are considered central for immune mediated demyelination. To examine the role of MAC in immune mediated demyelination, we studied experimental allergic neuritis (EAN) in Lewis rats deficient in complement component 6 (C6) that cannot form MAC. A C6 deficient Lewis (Lewis/C6−) strain of rats was bred by backcrossing the defective C6 gene, from PVG/C6− rats, onto the Lewis background. Lewis/C6− rats had the same C6 gene deletion as PVG/C6− rats and their sera did not support immune mediated haemolysis unless C6 was added. Active EAN was induced in Lewis and Lewis/C6− rats by immunization with bovine peripheral nerve myelin in complete Freund's adjuvant (CFA), and Lewis/C6− rats had delayed clinical EAN compared to the Lewis rats. Peripheral nerve demyelination in Lewis/C6− was also delayed but was similar in extent at the peak of disease. Compared to Lewis, Lewis/C6− nerves had no MAC deposition, reduced macrophage infiltrate and IL-17A, but similar T cell infiltrate and Th1 cytokine mRNA expression. ICAM-1 and P-selectin mRNA expression and immunostaining on vascular endothelium were delayed in Lewis C6− compared to Lewis rats' nerves. This study found that MAC was not required for immune mediated demyelination; but that MAC enhanced early symptoms and early demyelination in EAN, either by direct lysis or by sub-lytic induction of vascular endothelial expression of ICAM-1 and P-selectin.

Selective expression and cellular localization of pro-inflammatory chemokine ligand/receptor pairs in the sciatic nerves of a severe murine experimental autoimmune neuritis model of Guillain-Barré syndrome

To determine if specific pro-inflammatory chemokine ligand/receptor pairs expressed in the peripheral nerves of Guillain-Barré syndrome patients are expressed in a severe murine experimental autoimmune neuritis (sm-EAN) model and to determine their cellular localization as a prerequisite to designing potentially therapeutic interventions in vivo. Sm-EAN was induced in 8-12-week-old female SJL/J mice using bovine peripheral nerve myelin emulsified in complete Freund adjuvant with pertussis toxin and recombinant mouse interleukin-12 acting as co-adjuvants, with appropriate controls. Mice were evaluated for neuromuscular weakness and weighed daily. Dorsal caudal tail and sciatic nerve motor electrophysiological studies were performed at expected maximal severity. Sciatic nerves were harvested and specific chemokine ligand/receptor expression was determined using real-time quantitative reverse transcriptase polymerase chain reaction and indirect fluorescent immunohistochemistry. CCL2/CCR2, CXCL10/CXCR3 and CCL5/CCR1, CCR5 expression was significantly increased in the sciatic nerves of sm-EAN mice compared with controls. CCL2 was expressed on Schwann cells with CCR2 expressed on F4/80+ macrophages and CD3+ T cells. CXCL10 was expressed on endoneurial endothelial cells and within the endoneurial interstitium, with CXCR3 expressed on CD3+ T-lymphocytes. CCL5 co-localized to axons, with CCR1 and CCR5 expression on F4/80+ macrophages and rare CD3+ T cells. This study suggests that CCL2 expressed by Schwann cells and CXCL10 expressed by endoneurial endothelial cells may induce F4/80+ macrophage and CD3+ T cell-mediated inflammation and demyelination in sm-EAN. CCL2-CCR2 and CXCL10-CXCR3 signalling pathways are potential targets for therapeutic intervention in peripheral nerve inflammation.

Th1-like cell responses to peripheral nerve myelin components over the course of experimental allergic neuritis in Lewis rats.

Experimental allergic neuritis (EAN) is a T cell-mediated animal model of Guillain-Barré syndrome characterized by inflammation and demyelination of peripheral nerves. EAN can be induced by immunization of rats with bovine peripheral nerve myelin (BPM) or the myelin proteins P2 or P0, but the extent of T cell responses over the course of EAN is incompletely defined. We studied the T cell responses to these proteins and the glycolipid GM1 by enumerating T helper type 1 (Th1)-like cells secreting interferon-gamma (IFN-gamma) after short-term culture of mononuclear cells (MNC) in presence of antigen. Already 7 days post immunization (p.i.) with BPM and before onset of clinical EAN, lymph nodes contained elevated levels of P2 responsive T cells. At the height of EAN on day 14 p.i. and during recovery, T cell levels responding to BPM, P0 and GM1 were also elevated. The same temporal profiles and specificities were registered for antigen reactive spleen MNC. The results implicate that Th1-like cells with multiple specificities including the glycolipid GM1 occur at increased levels in lymphoid organs in EAN rats, and that IFN-gamma may be an important effector molecule in the induction of nerve damage.

Improving Anti-CD45 Antibody Radioimmunotherapy Using a Physiologically Based Pharmacokinetic Model

Radioimmunotherapy is a method to selectively deliver radioactivity to cancer cells via specific antibodies. A strategy to enhance the efficacy of radioimmunotherapy is the prior application of unlabeled antibody, resulting in an increase in the dose to the target tissue and a decrease in the burden to other organs. It was suggested that optimizing this approach might considerably improve radioimmunotherapy with anti-CD45 antibody. The present work develops a physiologically based pharmacokinetic model to individually determine the optimal preload for radioimmunotherapy with the YAML568 anti-CD45 antibody for each patient. A physiologically based pharmacokinetic model was developed to describe the biodistribution of anti-CD45 antibody. The transport of antibody to the organs of interest via blood flow, competitive binding of unlabeled and labeled antibody, degradation and excretion of antibody, and physical decay were included in the model. The model was fitted to the biokinetics data of 5 patients with acute myeloid leukemia. On the basis of the estimated parameters, simulations for a 0- to 534-nmol preload of unlabeled antibody were conducted and the organ residence times were calculated. The measured data could be adequately described by the constructed model. The estimated numbers of accessible antigens in the respective organ, in nanomoles, were 97+/-33 for red marrow, 49+/-24 for liver, 34+/-18 for spleen, 38+/-31 for lymph nodes, and 0.9+/-0.4 for blood. These ranges indicate high interpatient variability. The optimal amount of unlabeled antibody identified by simulations would improve the ratio of residence time in red marrow to residence time in liver by a factor of 1.6-2.4. The efficacy of radioimmunotherapy using anti-CD45 antibody can be considerably increased with the presented model. A more selective delivery of radioactivity to the target organ and a reduction in the toxicity to normal tissue are achieved by determining the optimal preload. Furthermore, the adverse effects of radioimmunotherapy might be drastically reduced while saving antibody expenses. The validation of the model is ongoing. The model is easily extendible and therefore most probably applicable to radioimmunotherapy of other hematologic malignancies, such as antibodies targeted to CD20, CD33, or CD66.

Cellular mRNA expression of interferon-gamma, IL-4 and transforming growth factor-beta (TGF-beta) by rat mononuclear cells stimulated with peripheral nerve myelin antigens in experimental allergic neuritis.

Experimental allergic neuritis (EAN) serves as a useful model for inflammation in the peripheral nervous system. To study the potential role of important immunoregulatory and effector cytokines in EAN, we examined the expression of mRNA for interferon-gamma (IFN-gamma), IL-4 and TGF-beta by in situ hybridization in lymph node and splenic cells cultured with bovine peripheral nerve myelin (BPM), P2 and P0 during the course of EAN in Lewis rats. Levels of IFN-gamma mRNA-expressing mononuclear cells (MNC) from lymph nodes and spleens roughly correlated with clinical status, consistent with a disease-promoting role for IFN-gamma. BPM, P0 and P2-reactive IFN-gamma mRNA-expressing T cells appeared in lymph nodes and spleen before onset of the disease, whereas a significant TGF-beta response to BPM, P2 and P0 was observed at lower levels than the IFN-gamma response and at onset of recovery, consistent with a disease down-regulating role of TGF-beta. IL-4 mRNA-expressing cells were found at levels similar to TGF-beta mRNA-expressing cells, and with the latest peak of the three cytokines examined. This result suggests that IL-4 may also suppress IFN-gamma expression at late recovery phase of EAN.

Amino acid copolymer-specific IL-10-secreting regulatory T cells that ameliorate autoimmune diseases in mice.

IL-10-secreting regulatory T cell lines specific to glatiramer acetate [poly(Y,E,A,K)n] or poly(Y,F,A,K)n have been established from the enlarged spleen and lymph nodes that result from copolymer treatment of SJL mice in which experimental autoimmune encephalomyelitis was induced by PLP139-151. These CD4+CD25+T cell lines secrete high levels of IL-10 and IL-13 but only small amounts of IL-4 and virtually no TGF-beta, IL-17, IL-6, IFN-gamma, or TNF-alpha. Their phenotypes are particularly characterized by the absence of Foxp3 and the presence of two TNFR family members, CD30 and GITR. The lines proliferated specifically to the immunizing copolymers but were autoantigen-nonspecific, in that the same T cell line could suppress autoimmunity induced by three different autoantigens in SJL mice, i.e., PLP139-151(EAE), MBP85-99 (EAE), and bovine peripheral nerve myelin (experimental autoimmune neuritis), indicating they function by bystander suppression.

647: CD4 + CD25 + T cells prevent induction of demyelination in experimental allergic neuritis (EAN)

Immune tolerance is induced and maintained by T cells, which express CD4 and CD25s the IlI-2 receptor alpha chain. We examine the role of these cells in Lewis rats that had recovered from EAN and were resistant to further disease induction. The CD4+CD25+ and CD4+CD25- T cell subsets were prepared form Lewis rats that had recovered from EAN and from normal Lewis rats and their function compared. First we transferred 5x106 CD4+CD25+ T cells on the day of immunization with bovine peripheral nerve myelin (n=12), these cells suppressed severity of disease to peak at a mean score of 1, compared to controls (n=10) peaking at 2.5 and those given 5×106 CD4+CD25– T cells which peaked at 3 (n=5).

Effective treatment of experimental autoimmune neuritis with Fc fragment of human immunoglobulin

IV immunoglobulin (IVIg) and its Fc fragment proved effective in preventing further progression of experimental autoimmune neuritis (EAN) in the rat induced by whole bovine peripheral nerve myelin and shortening disease duration. This effectiveness was associated with significant differences in electrophysiological parameters including less prolongation of somatosensory evoked potential (S wave) latencies, better maintained S wave amplitudes, less reduction of distal motor nerve conduction velocity, and better maintained amplitudes of compound muscle action potentials of dorsal foot muscles after stimulation at ankle and hip. Moreover, treatment with IVIg and Fc fragments resulted in less extensive inflammation and demyelination in nerve roots evidenced by significantly lower histological grades. The current study provides direct evidence for the first time that Fc fraction of IVIg is the effective component in the treatment of rat EAN.

B cells play a cooperative role via CD40L–CD40 interaction in T cell-mediated experimental autoimmune neuritis in Lewis rats

The expression of co-stimulatory molecules CD40 and CD40L was examined over the course of experimental autoimmune neuritis (EAN) induced in Lewis rats by immunization with bovine peripheral nerve myelin. In draining lymph nodes, highest level of CD40L expression was seen on day 7 post immunization (p.i.), i.e. before onset of clinical signs of EAN, while CD40 expression was increased on day 14 p.i., i.e. at peak of clinical disease. In contrast, both CD40 and CD40L expressing cells in sciatic nerves, a target organ of EAN, peaked on day 14 p.i., large numbers of both expressing cells were mainly detected on day 14-21 p.i. After co-culture with EAN rat B cells bearing CD40, P0 peptide 180-199-specific T cell line cells exhibited a rapid down-regulation of CD40L expression. Furthermore, EAN rats had enhanced P0 peptide 180-199-specific antibody responses on day 14 p.i., which might have contributed to their aggravated EAN and further demonstrated the role of antibodies in EAN. The results indicate that CD40L-CD40 interactions are involved in the initiation of the antigen-specific T cell responses associated with the generation and development of EAN, and may mediate autoantibody production in EAN. Evidently, B cells play a cooperative role via CD40L-CD40 interaction in T cell-mediated EAN of Lewis rats.

Characterization of glial cell line‐derived neurotrophic factor family receptor α‐1 in peripheral nerve Schwann cells

Glial cell line-derived neurotrophic factor (GDNF) family receptor alpha-1 (GFRalpha-1) is a receptor component of GDNF that associates with and activates the tyrosine kinase receptor Ret. To further understand GDNF and its receptor system in the PNS, we first characterized the expression of GFRalpha-1 in bovine peripheral nerve in vivo. GFRalpha-1 immunoreactivity was localized adjacent to the outermost layer of myelin sheath, as well as in the endoneurium and axoplasm. In a fractionation study, GFRalpha-1 was recovered mostly in the soluble fraction, although a small amount was recovered in the membrane fraction. A substantial amount of GFRalpha-1 in the membrane fraction was extractable by detergent and alkaline conditions. To further clarify the expression of GFRalpha-1 in Schwann cells, we examined cultured rat Schwann cells and the Schwannoma cell line RT4. Schwann cells expressed GFRalpha-1 in both the soluble/cytosolic and membrane fractions, and the membrane form of GFRalpha-1 was expressed at the outer surface of the Schwann cell plasma membrane. We also confirmed the secretion of the soluble form of GFRalpha-1 from Schwannoma cells in a metabolic labeling experiment. These data contribute to our knowledge of the production, expression and functions of GFRalpha-1 in the PNS.

Lipooligosaccharide of Campylobacter jejuni prevents myelin-specific enteral tolerance to autoimmune neuritis—a potential mechanism in Guillain-Barré syndrome?

Campylobacter jejuni-induced enteritis is the most common infection preceding Guillain-Barré syndrome (GBS), an immune-mediated polyradiculoneuritis. The acute autoimmune attack is thought to be based on C. jejuni antigens which may mimick antigens of the peripheral nervous system. Additional pathomechanisms, like disturbance of natural T cell immunoregulation by C. jejuni, have not been evaluated so far. In experimental autoimmune neuritis (EAN), a T lymphocyte-mediated animal model of human GBS, tolerance to myelin-derived autoantigens can be induced by oral feeding of the respective antigen. Here we investigated whether the lipooligosaccharide (LOS) fraction of C. jejuni may directly alter immunologic tolerance through gastrointestinal pathways. While EAN, actively induced by immunization with bovine peripheral nerve myelin could be ameliorated by precedent feeding of myelin, feeding of C. jejuni LOS along with the myelin antigen not only prevented the tolerizing effects of oral myelin but even accelerated the onset of overt EAN and augmented the myelin-specific B cell response. These findings provide evidence that LOS of C. jejuni, as produced in the gut during C. jejuni-induced enteritis, can disturb natural tolerance to definite proteins which may be or may mimic peripheral nerve antigens. In human patients this may be one of the potential mechanisms to explain why C. jejuni enteritis is a common trigger of GBS.

Biphasic form of experimental autoimmune neuritis in dark agouti rats and its oral therapy by antigen‐specific tolerization

A new and biphasic form of experimental autoimmune neuritis (EAN) is described in dark agouti rats (DA rats) and is inducible by a single immunization with bovine peripheral nerve myelin (BPM) in complete Freund's adjuvant (DA-EAN). Animals develop a mild episode of disease; after recovery, 66-100% of the rats suffer from a more severe bout of EAN with paraparesis 25-30 days after immunization. By histology, DA-EAN is an inflammatory and demyelinating polyradiculoneuropathy virtually without axonal damage. Demyelination affects mainly spinal roots. This is also reflected by markedly increased F-wave latencies in nerve conduction studies of sciatic nerves. In sciatic nerves, inflammation and demyelination are found only focally and may be the histopathologic basis for conduction failure in some fibers. Immunologic investigations revealed stronger proliferative responses of DA than of Lewis rat lymph node cells to BPM and various peptides derived from the P2 protein. Proliferative and Th1-cytokine responses were particularly pronounced in spleen during the late phase of DA-EAN as compared to the monophasic EAN of Lewis rats. The data suggest that persistent lymphocyte proliferation with secretion of interferon (IFN)-gamma may be relevant for the relapsing course of DA-EAN whereas epitope spreading may explain the increased severity of the second bout of disease. The extended Th1 response in DA rats did not go along with a lack of downregulatory mechanisms, because the second DA-EAN attack was self-limited and splenocytes from DA rats produced considerable amounts of interleukin (IL)-10 and transforming growth factor (TGF)-beta. To substantiate further a functional immunoregulation in DA rats, we modulated DA-EAN by antigen-specific oral tolerization, which is known to involve active suppressor mechanisms. Preventive feeding of BPM in combination with cholera toxin (CT) induced a long-lasting resistance to DA-EAN. Even therapeutic administration of BPM or BPM/CT after onset of signs of disease significantly mitigated the further course of disease and prevented development of paraparesis. Because DA-EAN is easily inducible and leads consistently to relapses in most rats, it can be used for studies of immune factors that determine a relapsing course of autoimmunity. Furthermore, DA-EAN may serve as a model for relapsing inflammatory demyelinating polyneuropathies such as chronic inflammatory demyelinating polyneuropathy (CIDP) and for treatment studies. Our findings on effective prevention and therapy of DA-EAN by oral application of myelin/CT corroborate this form of immunomodulation as a treatment strategy for cell-mediated processes in chronic inflammatory neuropathies.

Characterization of parkin in bovine peripheral nerve

The autosomal recessive juvenile parkinsonism is caused by the mutations of the gene encoding a novel protein called parkin. It has been reported that parkin is expressed in the central nervous system and functions as a ubiquitin-protein ligase (E3) which suppresses neuronal cell degeneration by ubiquitinating misfolded proteins. Thus far, however, it remains unknown if parkin is expressed and functions in the peripheral nervous system. In order to begin to address to this question, we investigated the expression of parkin in bovine peripheral nerve. Reverse transcription polymerase chain reaction analysis demonstrated the presence of parkin transcript in bovine peripheral nerve. The obtained bovine parkin cDNA sequence was identical to that of human except a single nucleotide. Immunoblot analysis demonstrated the expression of parkin protein in bovine peripheral nerve. Immunohistochemical analysis demonstrated the localization of parkin in the axoplasm of myelinated nerve fibers, the Schwann cell cytoplasm and the Schwann cell outer membrane. Furthermore, fractionation analysis indicated the presence of two fractions of parkin in bovine peripheral nerve, the cytosolic fraction and the cell membrane-bound fraction. All together, these results point to diverse roles of parkin in not only the central but also the peripheral nervous system.

A possible novel isoform of peripheral myelin P0 protein: a target antigen recognized by an autoantibody in a patient with malignant lymphoma and peripheral neuropathy

We tried to characterize a 35-kD antigen recognized by the serum IgG of a patient with malignant lymphoma and peripheral neuropathy. By Western blotting, the serum IgG reacted with the 35-kD antigen in the human, bovine and mouse peripheral nerve (PN) but not with other neural and non-neural tissues. Immunohistochemical analysis showed immunoreactivity of the IgG in the compact myelin of PN. We constructed a human sciatic nerve cDNA library and screened it using IgG of the patient. Three independent clones were obtained. Sequence alignment indicated that the inserts of these clones were homologous to the P0 cDNA, but that all three corresponded to the 3′-untranslational region of the P0 cDNA. To biochemically analyze the 35-kD antigen, myelin fractions of the human and bovine PN were prepared. The 35-kD antigen was purified from the crude myelin fraction by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. When the immunoreactivities of the 35-kD antigen for the IgG of the patient and a monoclonal anti-P0 antibody were compared with those of P0 protein for these antibodies, the 35-kD antigen reacted with both antibodies, but the P0 protein reacted with only the monoclonal anti-P0 antibody. These results suggest that the 35-kD antigen is an isoform of P0 protein. Although it is unlikely that the autoantibody may be the primary cause of neuropathy, because they were also detected in patients with lymphoma without overt neuropathy, they appear to be a modifying factor in the progression of neuropathy.

Role Of Campylobacter Jejuni In Experimental Allergic Neuritis: A Morphological And Biochemical Study

Objective: The aim of the study was to evaluate if Campylobacter jejuni (C.j.) when used as an adjuvant would be able to produce a different form of Experimental Allergic Neuritis (EAN). We present here some preliminary results. Background: EAN is considered the in vivo model of Guillain‐Barrè Syndrome (GBS), which is often preceded by c.j. infection. EAN can be induced in Lewis rats by immunization with bovine peripheral nerve myelin in complete Freund's adjuvant (CFA), an emulsion formed by oil‐in‐water and dead mycobacteria. An adjuvant is usually necessary for the induction of EAN because it enhances the immunogenicity of the antigen. Clinically EAN is characterized by an acute monophasic course and progressive tail and limb weakness. The pathological finding is represented by marked demyelination affecting the roots and the sciatic nerve. Methods: 4 Lewis rats were immunized with an emulsion containing 2 mg of bovine peripheral myelin and C.j. strain Penner 0:41 in incomplete Freund's adjuvant (IFA). They were compared to 4 controls immunized with the same amount of peripheral myelin in CFA. The clinical course of the disease and the histological pattern of the roots and the sciatic nerve were examined. Anti‐peripheral myelin, anti‐C.jejuni and anti‐GM1 antibodies' reactivity was detected by an ELISA assay. A biochemical study was performed to test the role of cell‐ and humoral‐mediated responses. Results: The Lewis rats immunized with the C.j. as an adjuvant showed a delayed onset and a milder course of disease. Pathology in the roots was characterized by predominant demyelination, whereas the sciatic nerve presented very little signs of damage. Conclusion: This serotype of C.j. appears to be a less effective adjuvant in inducing EAN rather than Mycobacteria. Further studies are necessary to elucidate the pathogenetic mechanisms involved in GBS.

EXPERIMENTAL ALLERGIC NEURITIS IN THE SJL/J MOUSE: INDUCTION OF SEVERE AND REPRODUCIBLE DISEASE WITH BOVINE PERIPHERAL NERVE MYELIN AND PERTUSSIS TOXIN WITH OR WITHOUT INTERLEUKIN‐12

We report a reproducible model of experimental allergic neuritis (EAN) with severe clinical signs and consistent pathological features in mice. Pertussis toxin (PT) in the presence or absence of murine recombinant interleukin‐12 (mrIL‐12) was used as an adjuvant with bovine peripheral nerve myelin (BPNM) to induce clinical EAN in SJL/J mice. After immunization with a combination of BPNM in complete Freund's adjuvant (CFA) and PT, mice developed severe consistent signs of EAN. The additional treatment of immunized mice with mrIL‐12 prolonged the course of EAN characterized by earlier clinical signs of the disease and delayed the recovery stage. Mice injected with BPNM and CFA without PT developed mild clinical signs. Histological examination of the caudae equinae and the sciatic nerves taken from mice with clinical signs of EAN during the recovery stage revealed severe demyelination, remyelination and remnants of mononuclear cell infiltration. Moderate to severe EAN can be induced in SJL/J mice by the injection of a combination of BPNM in CFA and PT. This model can provide a better understanding of mechanism of demyelination in infiltrating peripheral neuropathy.