Immunocytochemical search for JC papovavirus large T-antigen in multiple sclerosis brain tissue

Characterization of Jc Virus Dna Amplified from Urine of Chronic Progressive Multiple Sclerosis Patients

Thirty-seven chronic progressive multiple sclerosis (MS) patients, 20 of whom were taking cyclosporine, were examined for excretion of JC virus (JCV) in the urine. Polymerase chain reaction (PCR) amplification of DNA in urinary cell extracts detected JCV in 30% of the MS urines. In the cyclosporine treated group four of 20 (20%) excreted JCV, whereas in the untreated group seven of 17 (41%) excreted JCV. Thus, cyclosporine treatment did not enhance urinary excretion of the virus. A control group consisting of an unselected series of 89 patients donating urine in a general medical clinic and 16 healthy volunteers showed 41% with detectable urinary JCV. Thirty-three percent of the control females excreted JCV (18154), as did 49% of the control males (25151). Although the percentage of MS patients excreting detectable virus was not increased compared to the control group, the presence of JCV in the urine provides or convenient source of the virus for further characterization. Genotyping of DNA fragments amplified from the VPI region indicates mainly the presence of JCV Type 1 in these chronic progressive MS patients. This is also the type that predominates in the control group. An apparent recombinant between Type 1 and Type 3 (African) within the VPI region, tentatively designated Type 113 (or Type 4), was found in both the MS group and the controls. A larger series of MS patients that includes relapsing/remitting disease will be required to determine whether the genotype profile of JCV excreted in the urine of MS patients differs significantly from controls.

JC virus latency in the brain and extraneural organs of patients with and without progressive multifocal leukoencephalopathy

JC virus (JCV) is latent in the kidneys and lymphoid organs of healthy individuals, and its reactivation in the context of immunosuppression may lead to progressive multifocal leukoencephalopathy (PML). Whether JCV is present in the brains or other organs of healthy people and in immunosuppressed patients without PML has been a matter of debate. We detected JCV large T DNA by quantitative PCR of archival brain samples of 9/24 (38%) HIV-positive PML patients, 5/18 (28%) HIV-positive individuals, and 5/19 (26%) HIV-negative individuals. In the same samples, we detected JCV regulatory region DNA by nested PCR in 6/19 (32%) HIV-positive PML patients, 2/11 (18%) HIV-positive individuals, and 3/17 (18%) HIV-negative individuals. In addition, JCV DNA was detected in some spleen, lymph node, bone, and kidney samples from the same groups. In situ hybridization data confirmed the presence of JCV DNA in the brains of patients without PML. However, JCV proteins (VP1 or T antigen) were detected mainly in the brains of 23/24 HIV-positive PML patients, in only a few kidney samples of HIV-positive patients, with or without PML, and rarely in the bones of HIV-positive patients with PML. JCV proteins were not detected in the spleen or lymph nodes in any study group. Furthermore, analysis of the JCV regulatory region sequences showed both rearranged and archetype forms in brain and extraneural organs in all three study groups. Regulatory regions contained increased variations of rearrangements correlating with immunosuppression. These results provide evidence of JCV latency in the brain prior to severe immunosuppression and suggest new paradigms in JCV latency, compartmentalization, and reactivation.

Induction of experimental autoimmune encephalomyelitis in Lewis rats by a viral peptide with limited homology to myelin basic protein

Viral infections are thought to play an important role in the pathogenesis of multiple sclerosis potentially through molecular mimicry, but direct evidence from humans and animal models remains inadequate. Based on the fact that amino acid homology has been found between viral and host encephalitogenic protein, we designed four viral peptides (peptides of HBV polymerase protein, large T protein of JC virus, EB virus DNA polymerase and alkaline exonuclease of Human herpesvirus 6) with limited homology to myelin basic protein and explored their clinical, immunological and histological characteristics in Lewis rats. The immunization with JC virus peptide induced slight clinical signs of EAE in Lewis rats. Immunological examination indicated that rats immunized with JC virus peptide triggered T-cell cross-reactivity against MBP68-86, but failed to induce antibody cross-reactivity with MBP68-86. Histological staining exhibited the infiltration of inflammatory T cells and the activation of microglia in spinal cords of rats immunized with MBP68-86 and JC virus peptide. Other three peptides had negative findings in Lewis rats. These results suggested that molecular mimicry could be an important factor in the pathogenesis of EAE induced with JC virus peptide by expanding a population of reactive T cells that recognize MBP68-86 in Lewis rats inferring a possible pathogenesis for molecular mimicry in MS.

Human demyelinating disease and the polyomavirus JCV

Many human neurological diseases involve demyelination of the central and/or peripheral nervous systems. These include the hereditary leukodystrophies--which have a genetic basis; multiple sclerosis (MS)--where the underlying cause of demyelination remains unknown; and progressive multifocal leukoencephalopathy (PML)--where the etiology is well-established as being viral. The human neurotropic polyomavirus--JC virus (JCV)--is the etiologic agent of PML, a fatal demyelinating disease of the central nervous system that occurs mainly in immunosuppressed patients, especially those with HIV/AIDS. JCV belongs to the polyomavirus family of tumor viruses that are characterized by non-enveloped icosahedral capsids containing small, circular, double-stranded DNA genomes. Serological studies have shown that JCV is widespread throughout the human population, but infections are usually restricted by the immune system, particularly cell-mediated immunity, causing the virus to enter a latent phase. An important corollary of this is that situations of severe immunosuppression may permit JCV to replicate and are thus a risk factor for PML.

Detection of JC virus DNA in cerebrospinal fluid from multiple sclerosis patients

JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), has been proposed as a possible aetiopathogenic factor in multiple sclerosis (MS). We performed a study to search the LT region of JCV genome by nested PCR in cerebrospinal fluid (CSF), peripheral blood mononuclear cell (PBMC) and urine samples collected from 121 MS patients, 24 patients with other neurological disorders (OND), 30 non neurological patients (NND) and in PBMCs and urine of 40 healthy subjects. JCV DNA has been found in the CSF of 11 MS patients (9%) while all the CSFs from the 24 OND and the 30 NND cases were negative. No significant differences have been observed as regard to the frequency of JCV DNA detection in PBMCs and urine between the MS patients and the control groups. Nucleotide sequences analysis of seven JCV CSF isolates showed that five strains were identical the prototypal strain, while the other two had a base mutation (T-->C) in 4286 nucleotide (nt). The finding of JCV DNA in the CSF of MS patients suggest that JCV could play a role in the triggering and/or in the maintenance of MS aetiopathogenic process, and therefore it should be taken in consideration when monitoring this disease.

Lack of JC viral genomic sequences in multiple sclerosis brain tissue by polymerase chain reaction

With DNA extracted from brain specimens from 19 multiple sclerosis, 5 progressive multifocal leukoencephalopathy, 1 Alzheimer's disease, and 8 nonneurological control subjects, polymerase chain reaction was performed using nested sets of primer pairs amplifying segments of the large T and VP1 antigen-encoding sequences of JC virus. Both sequences were detected in each of the 5 brain specimens of progressive multifocal leukoencephalopathy but in none of the 19 multiple sclerosis, 1 Alzheimer's disease, or the 8 control brain specimens.

Detection of JC virus in the brains of aged patients without progressive multifocal leukoencephalopathy by the polymerase chain reaction and Southern hybridization analysis

Ninety-one brain tissue sections taken at autopsy from 33 elderly patients (63-100 years old) without progressive multifocal leukoencephalopathy were examined for the presence of JC virus DNA by the polymerase chain reaction and Southern hybridization analysis after DNA extraction. JC virus DNA was detected in 15 sections from 10 patients. These results suggest that JC virus is frequently present in the brains of aged patients.

A double-label method detects both early (T-antigen) and late (capsid) proteins of JC virus in progressive multifocal leukoencephalopathy brain tissue from AIDS and non-AIDS patients

A new double-label immunocytochemical method detects JC virus (JCV) early (T-antigen) and late (capsid) proteins simultaneously in cryostat sections of progressive multifocal leukoencephalopathy (PML) brain tissue from both acquired immunodeficiency syndrome (AIDS) and non-AIDS patients. T-antigen is detected with a monoclonal antibody (PAb 416) followed by goat anti-mouse IgG and mouse Clono-PAP, while capsid proteins are detected by a rabbit polyclonal antiserum to capsid proteins followed by biotinylated goat anti-rabbit IgG and streptavidin-alkaline phosphatase conjugate. The substrates are 3,3'-diaminobenzidine and Vector Red I, respectively. With this method some infected glial cells stain for late (capsid) antigens in the nucleus, while others show early protein (large T-antigen) immunoreactivity. The latter are likely to be astrocytes infected abortively or oligodendrocytes in the early stages of a productive JCV infection.

Inhibition of binding of hamster antibody to myelin basic protein by a synthetic triproline-containing peptide from JC virus T-antigen

Antisera raised against porcine myelin basic protein (MBP) in Syrian hamsters were assayed by an ELISA method. The specificity of a high-titered antiserum was probed with synthetic peptides representing a hexapeptide and a decapeptide of the JC virus (JCV) large T-antigen C-terminus which is homologous to the MBP triproline region, a decapeptide from MBP which is encephalitogenic in guinea pigs, and peptides unrelated to MBP, i.e., substance P and poly-L-lysine. In an ELISA inhibition assay, preincubation of the hamster antiserum to MBP with either the JCV T-antigen C-terminal decapeptide or the encephalitogenic determinant inhibited binding activity in a dose-dependent manner. In contrast, the T-antigen C-terminal hexapeptide, substance P, and poly-L-lysine were not inhibitory. These results suggest that the triproline region of MBP can be immunogenic in hamsters, and support the concept that a conformation of the MBP triproline region is shared with certain of its viral homologues. In an effort to detect similar cross-reactive specificities in hamster antisera to JCV T-antigen, sera of 50 hamsters bearing subcutaneous tumors induced by JCV-transformed glial cells were tested for ability to bind to MBP in the ELISA assay. While significant increases in response compared to prebleed levels were observed in about one-fourth of the sera, some of them showed similar increases in binding to other basic proteins such as histones, and the binding to MBP was not inhibited by the triproline-containing decapeptide.