Comprehensive immunohistochemical studies on canine necrotizing meningoencephalitis (NME), necrotizing leukoencephalitis (NLE), and granulomatous meningoencephalomyelitis (GME)

In dogs, there are several idiopathic meningoencephalitides, such as necrotizing meningoencephalitis (NME), necrotizing leukoencephalitis (NLE), and granulomatous meningoencephalomyelitis (GME). Although they are often assumed to be immune mediated, the etiology of these diseases remains elusive. In this study, the histopathology of the lesions caused by these conditions and the inflammatory cell populations produced in response to them were examined among dogs affected with GME, NME, or NLE to understand their pathogeneses. The brain tissues of dogs with NME (n = 25), NLE (n = 5), or GME (n = 9) were used. The inflammatory cells were identified by immunohistochemistry using antibodies against CD3, IgG, CD20, CD79acy, and CD163. In NME and NLE, malacic changes were located in the cerebral cortex, as well as the cerebral white matter and thalamus, respectively. The distribution of the brain lesions in NME and NLE was breed specific. In GME, granulomatous lesions that were mostly composed of epithelioid macrophages were observed in the cerebral white matter, cerebellum, and brainstem. Although the proportions of IgG-, CD20-, and CD79acy-positive cells (B cells) were not significantly different among the GME, NME, and NLE lesions, that of CD3-positive cells (T cells) was increased in GME. In NME and NLE, CD163-positive cells (macrophages) had diffusely infiltrated the cerebral cortex and white matter, respectively. However, in GME, CD163-positive cells accumulated around the blood vessels in the cerebral and cerebellar white matter. The distributions of these lesions were quite different among GME, NME, and NLE, whereas there were no marked differences in the proportions of inflammatory cells.     

Glial fibrillary acidic protein (GFAP) and anti-GFAP autoantibody in canine necrotising meningoencephalitis

To establish clinical markers for canine necrotising meningoencephalitis (NME) and to elucidate its pathogenesis, glial fibrillary acidic protein (GFAP) and anti-GFAP autoantibodies were measured in the cerebrospinal fluid (CSF) of 32 dogs with NME, 23 dogs with other inflammatory central nervous system (CNS) diseases, 27 dogs with miscellaneous CNS diseases and 25 healthy dogs, including five pugs. The dogs with NME had the highest levels of anti-GFAP autoantibodies. The diagnostic sensitivity and specificity of anti-GFAP autoantibodies for NME were 91 per cent and 73 per cent, respectively. Some of the dogs with NME and the healthy pugs, had high CSF concentrations of GFAP, suggesting a breed-specific fragility of astrocytes. The leakage of GFAP and the development of autoimmunity may be key to understanding the pathogenesis of NME.     

Polymerase chain reaction screening for DNA viruses in paraffin-embedded brains from dogs with necrotizing meningoencephalitis, necrotizing leukoencephalitis, and granulomatous meningoencephalitis

The objective of this investigation was to determine whether or not herpesvirus (herpes-), adenovirus (adeno-), or canine parvovirus DNA is present in the brains of dogs with necrotizing meningoencephalitis (NME), necrotizing leukoencephalitis (NLE), and granulomatous meningoencephalitis (GME). Paraffin-embedded brain specimens from 12 histopathologically confirmed dogs with NME, 3 with NLE, and 7 with GME were screened for viral DNA with degenerate herpes- and adenovirus polymerase chain reaction (PCR) and a canine parvovirus-specific PCR. Positive-control specimens included genomic viral DNA and paraffin-embedded tissues from dogs with confirmed herpes-, adeno-, or canine parvovirus infections. Herpes-, adeno-, or canine parvovirus DNA was amplified by PCR from the corresponding positive-control specimens. Negative controls included 7 dogs with various brain disorders and produced no viral amplicons. The 22 dogs with NME, NLE, and GME were negative for viral DNA. Additional studies testing for other viruses or inherited genetic mutations are warranted to gain insight into the etiologies of NME, NLE, and GME. We discuss potential etiologies and provide a clinical and histopathologic overview of these common canine encephalitides.     

Prevalence of autoantibody in cerebrospinal fluids from dogs with various CNS diseases

To examine the prevalence of autoantibody in canine cerebrospinal fluids (CSFs), CSFs were collected from 14 healthy controls and 88 clinical cases with various diseases in the central nervous system (CNS), and were analyzed by an indirect fluorescence antibody test on frozen sections of the cerebrum from normal Beagle dogs. An anti-astrocyte autoantibody was detected in 31 clinical cases with titers ranging from 1:1 to >/=1:100. All tested cases with necrotizing meningoencephalitis (NME: n=22) and granulomatous meningoencephalitis (GME: n=3) possessed the anti-astrocyte autoantibody, while the autoantibody was negative in most cases with other inflammatory CNS diseases. The autoantibody was also detected in 4 of 12 cases with brain tumors. Hence, examination of the autoantibody in the canine CFS would be significant for diagnosing NME and/or GME, as well as for understanding peritumoral events in cases with brain tumors.     

Autoantibodies against glial fibrillary acidic protein (GFAP) in cerebrospinal fluids from Pug dogs with necrotizing meningoencephalitis

Cerebrospinal fluids (CSFs) from 9 Pug dogs with necrotizing meningoencephalitis (NME: Pug dog encephalitis) were examined to identify the antigens for anti-astrocyte autoantibodies. Each CSF exhibited a positive reaction to the cytoplasm of cultured canine astrocytes by an indirect fluorescent antibody test. In an immunoblotting analysis on normal canine brain proteins, eight of 9 CSFs showed a common band of 52 kDa, corresponding to glial fibrillary acidic protein (GFAP), and all of 9 CSFs reacted with purified bovine GFAP. From these results, GFAP is one of the common autoantigens in Pug dogs with NME. On the other hand, the reactivity of CSFs to chymotrypsin-digested bovine GFAP fragments were variable among dogs, indicating that the antibodies in the CSFs recognized different epitopes on GFAP.     

Autoantibodies against structures of the central nervous system in steroid responsive meningitis-arteriitis in dogs

Steroid-responsive meningitis-arteriitis (SRMA) is a disease of dogs familiar in small animal practice for decades. A combined evaluation of IgA in serum and cerebrospinal fluid (CSF) is an important diagnostic tool. It is suspected that immunpathological mechanisms are involved in the pathogenesis of SRMA because of the marked response to steroids. Excessive production of IgA seems to play a central role and might be caused by an immune reaction to self-antigens of the central nervous system (CNS). To test this hypothesis, we analyzed CSF samples from 55 dogs with SRMA using the western blot method. After blotting canine brain tissue, IgA, IgM and IgG of the CSF samples were tested for their binding to CNS antigens. We also evaluated CSF samples from 45 dogs with other brain diseases, including different encephalitides and intracranial tumors, and from healthy dogs as controls. Positive reactions (mostly IgA) were observed in the CSF samples from dogs with SRMA, different encephalitides and brain tumors (a total of 8% positive samples). The occurrence of autoantibodies against CNS structures was significantly higher in the control group "other brain diseases" than in the SRMA group (p = 0.0135). There was no significant difference in the number of positive samples between dogs with SRMA and the negative control group (healthy dogs, p = 0.1535). Despite the small number of positive samples, only dogs with abnormal findings in the CSF analysis also had autoantibodies in the CSF. There was no significant correlation between the occurrence of autoantibodies and levels of IgA, protein content and cell counts in the cerebrospinal fluid. However, there was a certain trend toward positive reactions in CSF samples with high protein content. The occurrence of autoantibodies in dogs with SRMA thus seems to be an epiphenomenona rather than the cause of the disease.     

Determination of immunoglobulin A concentrations in the serum and cerebrospinal fluid of dogs: an estimation of its diagnostic value in canine steroid-responsive meningitis-arteritis

Previous studies on canine steroid-responsive meningitis-arteritis (SRMA) suggested that elevation of immunoglobulin A (IgA) concentrations in both serum and cerebrospinal fluid (CSF) is specific for SRMA throughout the different disease stages. Recent studies however have raised concerns about the value of this test. The purpose of this study was to investigate the diagnostic value of IgA concentration testing in paired CSF and serum samples. IgA concentrations of 525 paired canine CSF and serum samples were evaluated. Samples were obtained from dogs with SRMA (n=311) and dogs with miscellaneous conditions (n=214) such as other central nervous system (CNS) inflammatory diseases (n=34), CNS tumours (n=46), idiopathic epilepsy (n=42), intervertebral disc disease (n=46) and non-CNS diseases (n=46). Serum IgA concentrations were significantly higher in dogs with untreated SRMA compared to those with other diseases. IgA CSF concentrations were significantly higher in dogs with SRMA compared to other disease categories, with the exception of inflammatory CNS disease. The sensitivity for IgA concentrations in serum and CSF was 91% with a specificity of 78%. Analysis of 525 paired samples confirmed that IgA concentrations were higher in dogs with SRMA. Calculation of the diagnostic value of IgA concentration confirmed that the test is highly sensitive for SRMA. Testing paired CSF and serum samples for IgA is still recommended for the diagnosis of suspected cases of SRMA.     

Evaluation of Brain Tissue or Cerebrospinal Fluid with Broadly Reactive Polymerase Chain Reaction for Ehrlichia,Anaplasma, Spotted Fever Group Rickettsia,Bartonella, and Borrelia Species in Canine Neurological Diseases (109 Cases)

Background: Vector‐transmitted microorganisms in the genera Ehrlichia, Anaplasma, Rickettsia, Bartonella, and Borrelia are commonly suspected in dogs with meningoencephalomyelitis (MEM), but the prevalence of these pathogens in brain tissue and cerebrospinal fluid (CSF) of dogs with MEM is unknown. Hypothesis/Objectives: To determine if DNA from these genera is present in brain tissue and CSF of dogs with MEM, including those with meningoencephalitis of unknown etiology (MUE) and histopathologically confirmed cases of granulomatous (GME) and necrotizing meningoencephalomyelitis (NME). Animals: Hundred and nine dogs examined for neurological signs at 3 university referral hospitals. Methods: Brain tissue and CSF were collected prospectively from dogs with neurological disease and evaluated by broadly reactive polymerase chain reaction (PCR) for Ehrlichia, Anaplasma, Spotted Fever Group Rickettsia, Bartonella, and Borrelia species. Medical records were evaluated retrospectively to identify MEM and control cases. Results: Seventy‐five cases of MUE, GME, or NME, including brain tissue from 31 and CSF from 44 cases, were evaluated. Brain tissue from 4 cases and inflammatory CSF from 30 cases with infectious, neoplastic, compressive, vascular, or malformative disease were evaluated as controls. Pathogen nucleic acids were detected in 1 of 109 cases evaluated. Specifically, Bartonella vinsonii subsp. berkhoffii DNA was amplified from 1/6 dogs with histopathologically confirmed GME. Conclusion and Clinical Importance: The results of this investigation suggest that microorganisms in the genera Ehrlichia, Anaplasma, Rickettsia, and Borrelia are unlikely to be directly associated with canine MEM in the geographic regions evaluated. The role of Bartonella in the pathogenesis of GME warrants further investigation.     

Focal granulomatous meningoencephalomyelitis in a pup

Granulomatous meningoencephalomyelitis (GME) was diagnosed in an 8-month-old Maltese with signs of CNS disease. Serum immunoglobulin (Ig) G concentration was decreased, and CSF analysis revealed high concentrations of mononuclear WBC and IgG. Initial improvement of the pup's signs in association with prednisolone treatment and postmortem examination of CNS tissues confirmed GME. Granulomatous meningoencephalomyelitis occurs rarely in young dogs and the abnormal Ig concentrations in this pup's serum and CSF suggest that immune responses may have a role in the cause and/or pathogenesis of GME.     

Proteome analysis of cerebrospinal fluid in healthy beagles and canine encephalitis

We performed proteomics analysis of the cerebrospinal fluid (CSF) of healthy dogs and dogs with meningoencephalitis of unknown etiology (MUE). By comparing two-dimensional electrophoreses (2DE), an upregulated spot was found in MUE dogs. This protein was identified as a neuron-specific enolase (NSE) by analysis with MALDI-TOF mass spectrometry. In comparing dot blots using an antibody against NSE, the NSE levels in the CSF of MUE dogs was significantly higher than that of the controls. NSE is a diagnostic marker of neuroendocrine tumors, brain injury and spinal cord trauma in humans. It seems that the NSE concentration in the CSF is increased by cellular destruction in canine encephalitis. Though elevation of NSE may not be specific in canine encephalitis because the NSE level was increased in other CNS diseases, further study including measurement with serum is necessary.     

Significance of surface epithelial cells in canine cerebrospinal fluid and relationship to central nervous system disease

Background: The term “surface epithelium” is used to describe cells, including meningeal, choroid plexus, ependymal, and endothelial cells, that are found in human cerebrospinal fluid (CSF) and are difficult to distinguish cytologically. We hypothesized that the presence of surface epithelial cells in canine CSF was associated with specific diseases of the central nervous system (CNS). Objectives: In this retrospective study the frequency of surface epithelial cells in CSF from dogs with neurologic disease was investigated along with the potential association with age, specific type of CNS disease, and CSF total nucleated cell count (TNCC) and protein concentration. Methods: The frequency of surface epithelial cells in 359 canine CSF samples was analyzed for 5 disease groups: CNS neoplasia, CNS compression, CNS inflammation, idiopathic epilepsy, and miscellaneous diseases. Groups were also combined into those with and without expected meningeal involvement. Association of the presence of surface epithelial cells in CSF with age, disease type, and CSF TNCC and protein concentration was investigated. Results: Surface epithelial cells were found in 27 of 359 (7.5%) CSF samples: CNS neoplasia 2/30 (6.7%), CNS compression 7/64 (10.9%), CNS inflammation 1/39 (2.6%), idiopathic epilepsy 8/124 (6.5%), and miscellaneous diseases 9/102 (8.8%). Significant associations between surface epithelial cell presence in CSF and age, disease type, CSF TNCC, and CSF protein concentration were not found. Conclusions: The presence of surface epithelial cells was not related to a specific disease group or CSF changes in the studied population. Thus, the presence of surface epithelial cells should be interpreted carefully, as it could represent an incidental finding in CSF specimens.     

Detection of an autoantibody from Pug dogs with necrotizing encephalitis (Pug dog encephalitis).

An autoantibody against canine brain tissue was detected in the cerebrospinal fluid (CSF) and serum of two Pug dogs (Nos. 1 and 2) by indirect immunofluorescence assay (IFA). Dog No. 1, a 2-year-old male, exhibited severe depression, ataxia, and generalized seizures and died 2 months after the onset of symptoms. Dog No. 2, a 9-month-old male, exhibited severe generalized seizures and died 17 months after the onset of symptoms. Histopathologic examination revealed a moderate to severe multifocal accumulation of lymphocytes, plasma cells, and a few neutrophils in both the gray and white matter of the cerebrum in dog No. 1. In dog No. 2, the cellular infiltrates were mild, but there was a severe, diffuse, and multifocal necrosis in the cerebral cortex with prominent astrocytosis. With the aid of IFA using fluorescein isothiocyanate-labeled antidog IgG goat serum and a confocal imaging system, specific reactions for glial cells were detected in the CSF of these Pug dogs but not in six canine control CSF samples. Double-labeling IFA using CSF from these Pug dogs and a rabbit antiserum against glial fibrillary acidic protein (GFAP) revealed that the autoantibody recognized GFAP-positive astrocytes and their cytoplasmic projections. By immunoblot analysis, the autoantibody from CSF of these Pug dogs recognized two common positive bands at 58 and 54 kd, which corresponded to the molecular mass of human GFAP. The role of this autoantibody for astrocytes is not yet clear. However, if the presence of the autoantibody is a specific feature of Pug dog encephalitis, it will be a useful clinical diagnostic marker and a key to the pathogenesis of this unique canine neurologic disease.     

IgG autoantibodies directed against desmoglein 3 cause dissociation of keratinocytes in canine pemphigus vulgaris and paraneoplastic pemphigus

Pemphigus is a group of autoimmune blistering diseases of the skin and mucous membranes. In human patients with pemphigus vulgaris (PV) and paraneoplastic pemphigus (PNP), IgG autoantibodies against desmoglein (Dsg) 3 and Dsg1 play pathogenic roles in blister formation. In contrast, the target for IgG autoantibodies that induce keratinocyte dissociation has not been elucidated in canine pemphigus. The aim of the present study was to determine whether anti-Dsg IgG autoantibodies are present and disrupt the cell-cell adhesion of keratinocytes in canine PV and PNP. The extracellular domains of canine Dsg3 were recognized by IgG in 3/5 (60%) canine PV sera tested. IgG against the extracellular domains of canine Dsg1 was detected exclusively in two dogs that had PV with the mucocutaneous phenotype. In addition, anti-Dsg3 IgG was identified in canine PNP serum. Furthermore, incubation of normal human keratinocytes (NHK) with mucocutaneous canine PV serum and canine PNP serum resulted in dissociation of the NHK sheets, whereas the removal of anti-Dsg3 IgG from these canine sera blocked this dissociation. The present study indicates for the first time that circulating anti-Dsg3 IgG antibodies capable of dissociating keratinocytes are present in dogs with PV and PNP.     

Isotype determination of circulating autoantibodies in canine autoimmune subepidermal blistering dermatoses

Abstract The three most common canine autoimmune blistering skin diseases (AISBD), bullous pemphigoid (BP), mucous membrane pemphigoid (MMP) and epidermolysis bullosa acquisita (EBA) have recently been separated based on clinical, histological and immunological grounds. The objectives of this study were to determine the isotype profiles of circulating autoantibodies in these dermatoses. Serum was collected from 5 dogs with BP, 15 with MMP and 11 with EBA. All sera were tested using an indirect immunofluorescence method using salt-split canine gingiva as substrate. Anti-basement membrane IgG autoantibodies were detected in all patients. Among the IgG autoantibodies, IgG1 and IgG4 were encountered most frequently, while IgG2 and IgG3 were uncovered in some dogs. IgE autoantibodies were detected more often than IgA or IgM autoantibodies in any of the three entities. The predominance of IgG1, IgG4 and IgE autoantibody isotypes in dogs with AISBD is very similar to the situation found in humans with the homologous diseases.     

Correlation between fluorodeoxyglucose positron emission tomography and magnetic resonance imaging findings of non-suppurative meningoencephalitis in 5 dogs

This study characterized the [(18)F]2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) findings of encephalitis in dogs and assessed the role of FDG-PET in the diagnosis of meningoencephalitis. The medical records, magnetic resonance (MR), and FDG-PET images of 3 dogs with necrotizing meningoencephalitis (NME), 1 dog with granulomatous meningoencephalitis (GME), and 1 dog with meningoencephalitis of unknown etiology (MUE) were reviewed. On the FDG-PET, glucose hypometabolism was identified in the dog with NME, whereas hypermetabolism was noted in the dog with GME. The T2-weighted images (WI) and fluid attenuated inversion recovery (FLAIR) images were characterized by hyperintensity, whereas the signal intensity of the lesions on the T1-WI images was variable. The metabolic changes on the brain FDG-PET corresponded well to the hyper- and hypointense lesions seen on the MR imaging. This type of tomography (FDG-PET) aided in the differentiation of different types of inflammatory meningoencephalitis when the metabolic data was combined with clinical and MR findings.     

Anti-insulin antibodies in diabetic dogs before and after treatment with different insulin preparations

Background: Anti‐insulin antibodies (AIA) occur in diabetic dogs after insulin therapy, although their clinical significance is unclear. Hypothesis: Treatment of diabetic dogs with heterologous insulin is more likely to stimulate production of AIA than is treatment with homologous insulin. Animals: Diabetic dogs sampled before insulin therapy (n = 40), diabetic dogs sampled following treatment with porcine (homologous) insulin (n = 100), bovine (heterologous) lente insulin (n = 100), or bovine protamine zinc (PZI) insulin (n = 20), and nondiabetic control dogs (n = 120). Methods: Prospective observational study. Sera were analyzed by ELISA for antibodies against porcine insulin, bovine insulin, insulin A, B, or C peptides, and control antigens; canine distemper virus (CDV) and canine thyroglobulin (TG). Canine isotype‐specific antibodies were used to determine total and anti‐insulin IgG1 : IgG2 ratios. Results: There was no difference in CDV or TG reactivity among the groups. AIA were detected in 5 of 40 newly diagnosed (untreated) diabetic dogs. There was no significant difference in AIA (ELISA optical density reactivity) comparing control and porcine insulin‐treated diabetic dogs (P > .05). Anti‐insulin reactivity was most prevalent in bovine PZI insulin‐treated dogs (90%; P < .01), and bovine lente insulin‐treated dogs (56%; P < .01). AIA induced by treatment were enriched for the IgG1 isotype. Conclusions and Clinical Importance: This study indicates that bovine insulin is more immunogenic than porcine insulin when used for treatment of diabetic dogs.     

Detection of autoantibodies against thyroid peroxidase in serum samples of hypothyroid dogs

OBJECTIVE: To establish a sensitive test for the detection of autoantibodies against thyroid peroxidase (TPO) in canine serum samples. SAMPLE POPULATION: 365 serum samples from dogs with hypothyroidism as determined on the basis of serum concentrations of total and free triiodothyronine (T3), total and free thyroxine (T4), and thyroid-stimulating hormone, of which 195 (53%) had positive results for at least 1 of 3 thyroid autoantibodies (against thyroglobulin [Tg], T4, or T3) and serum samples from 28 healthy dogs (control samples). PROCEDURE: TPO was purified from canine thyroid glands by extraction with detergents, ultracentrifugation, and precipitation with ammonium sulfate. Screening for anti-TPO autoantibodies in canine sera was performed by use of an immunoblot assay. Thyroid extract containing TPO was separated electrophoretically, blotted, and probed with canine sera. Alkaline phosphatase-conjugated rabbit anti-dog IgG was used for detection of bound antibodies. RESULTS: TPO bands were observed at 110, 100, and 40 kd. Anti-TPO autoantibodies against the 40-kd fragment were detected in 33 (17%) sera of dogs with positive results for anti-Tg, anti-T4, or anti-T3 autoantibodies but not in sera of hypothyroid dogs without these autoantibodies or in sera of healthy dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The immunoblot assay was a sensitive and specific method for the detection of autoantibodies because it also provided information about the antigen. Anti-TPO autoantibodies were clearly detected in a fraction of hypothyroid dogs. The value of anti-TPO autoantibodies for use in early diagnosis of animals with thyroid gland diseases should be evaluated in additional studies.     

Use of anti-coronavirus antibody testing of cerebrospinal fluid for diagnosis of feline infectious peritonitis involving the central nervous system in cats

OBJECTIVE: To assess the use of measuring anti-coronavirus IgG in CSF for the diagnosis of feline infectious peritonitis (FIP) involving the CNS in cats. DESIGN: Prospective study. SAMPLE POPULATION: CSF and serum samples from 67 cats. PROCEDURES: CSF and serum samples were allocated into 4 groups: cats with FIP involving the CNS (n = 10), cats with FIP not involving the CNS (13), cats with CNS disorders caused by diseases other than FIP (29), and cats with diseases other than FIP and not involving the CNS (15). Cerebrospinal fluid was evaluated for concentrations of erythrocytes, leukocytes, and total protein. Anti-coronavirus IgG was measured in CSF and serum by indirect immunofluorescence assay. RESULTS: CSF IgG (range of titers, 1:32 to 1:4,096) was detected in 12 cats, including 6 cats with neurologic manifestation of FIP, 4 cats with FIP not involving the CNS, and 2 cats with brain tumors. Cerebrospinal fluid IgG was detected only in cats with correspondingly high serum IgG titers (range, 1:4,096 to 1:16,384) and was positively correlated with serum IgG titers (r = 0.652; P < 0.01), but not with any other CSF parameter. Blood contamination of CSF resulted in < or = 333 erythrocytes/microL in cats with CSF IgG. CONCLUSIONS AND CLINICAL RELEVANCE: The correlation between serum and CSF IgG and the fact that CSF IgG was detected only in strongly seropositive cats suggested that CSF anti-coronavirus IgG was derived from blood. Measurement of anti-coronavirus IgG in CSF was of equivocal clinical use.     

Impaired expression of excitatory amino acid transporter 2 (EAAT2) and glutamate homeostasis in canine necrotizing meningoencephalitis

To clarify the involvement of excitatory and inhibitory amino acids in canine necrotizing meningoencephalitis (NME), glutamate, aspartate, taurine and gamma-aminobutylic acid (GABA) were determined in the cerebrospinal fluids (CSF) from eight NME cases and ten healthy controls. NME dogs exhibited significantly higher concentrations of glutamate and aspartate than those in controls (p<0.001 and p<0.001, respectively), while there was no difference in taurine or GABA between the two groups. When fetal canine astrocytes were cultured for 24 hr in the presence of NME-CSF, supernatant concentrations of glutamate, aspartate and taurine were significantly elevated. Simultaneously, expression of excitatory amino acid transporter 2 (EAAT2) mRNA was significantly reduced in the astrocytes without change in EAAT1 mRNA. Hence, reduced expression of EAAT2 and impaired glutamate homeostasis may contribute to the pathogenesis of NME.     

The humoral immune response to recombinant nucleocapsid antigen of canine distemper virus in dogs vaccinated with attenuated distemper virus or DNA encoding the nucleocapsid of wild-type virus

This study compared the humoral immune response against the nucleocapsid-(N) protein of canine distemper virus (CDV) of dogs vaccinated with a multivalent vaccine against parvo-, adeno-, and parainfluenza virus and leptospira combined with either the attenuated CDV Onderstepoort strain (n = 15) or an expression plasmid containing the N-gene of CDV (n = 30). The vaccinations were applied intramuscularly three times at 2-week intervals beginning at the age of 6 weeks. None of the pre-immune sera recognized the recombinant N-protein, confirming the lack of maternal antibodies at this age. Immunization with DNA vaccine for CDV resulted in positive serum N-specific IgG response. However, their IgG (and IgA) titres were lower than those of CDV-vaccinated dogs. Likewise, DNA-vaccinated dogs did not show an IgM peak. There was no increase in N-specific serum IgE titres in either group. Serum titres to the other multivalent vaccine components were similar in both groups.