Pathogenesis and molecular biology of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain

The JC virus minimal core promoter is glial cell specific in vivo

The glial cell specificity of the human papovavirus JC (JCV), an etiologic agent for progressive multifocal leukoencephalopathy, is thought to be due to the presence of both positive and negative regulatory elements upstream of the TATA region within the JCV promoter. Here we report that the JCV minimal core promoter, containing only the TATA box and an 8-bp poly(T) region immediately upstream, is sufficient to initiate transcription of an attached gene in glial cells and functions as an autonomously active initiator. We further define the sequences required for this core promoter's glial cell specificity by appropriate substitution and point mutation analysis. Ectopic expression of Tst-1, a POU domain transcription factor that has been implicated in the regulation of oligodendrocyte development, leads to higher activation of the JCV minimal core promoter in Tst-1-deficient glial cells than in non-glial HeLa cells. These results suggest a requirement for a glial cell coactivator(s) for the optimum activation of the JCV minimal core promoter by Tst-1. A discrete affinity of Tst-1 for the JCV core promoter (Kd, 1.4 x 10(-8) M) is also shown to be optimal for its promoter strength. Mutations within the core promoter that maintain this affinity for Tst-1 show maintenance of promoter strength, whereas mutants carrying a change that results in an increased affinity for Tst-1 show reduced transcriptional activity. These results suggest that moderate affinity of Tst-1 for the JCV TATA region may allow the interaction of some glial cell-specific coactivator(s) along with the basal transcription machinery to direct glial cell-specific transcription from the JCV core promoter.

Cooperative action of cellular proteins YB-1 and Pur alpha with the tumor antigen of the human JC polyomavirus determines their interaction with the viral lytic control element

Human JC polyomavirus (JCV) is the etiologic agent of the neurodegenerative disease progressive mulifocal leukoencephalopathy. By using JCV as a model, we investigated the role of the viral early protein tumor antigen (TAg) in the binding of two cellular proteins, Pura alpha and YB-1, to JCV regulatory sequences. Results from band-shift assays with purified YB-1, Pur alpha, and TAg indicated that efficient binding of Pur alpha, a strong activator of early gene transcription, to a single-stranded target sequence corresponding to the viral lytic control element, is diminished in the presence of the late gene activator YB-1, which recognizes the opposite strand of the Pur alpha binding site. Of particular interest was the ability of Pur alpha and TAg to enhance binding of YB-1 to DNA molecules without being associated with this complex. Binding studies using a mutant peptide encompassing the N terminus of YB-1 indicated that the C terminus of YB-1 is important for its DNA binding activity. The ability of Pur alpha and TAg to increase binding of YB-1 to DNA is independent of the YB-1 C terminus. Similarly, results from band-shift assays using Pur alpha variants indicated that two distinct regions of this protein contribute either to its ability to bind DNA or to its ability to enhance YB-1 DNA binding activity. Based on the interaction of Pur alpha, YB-1, and TAg, and their binding to DNA, a model is proposed for the role of these proteins in transcription of viral early and late genes during the lytic cycle.

Identification and characterization of a novel GGA/C-binding protein, GBP-i, that is rapidly inducible by cytokines

Immunosuppressive states with accompanying alterations in cytokine profiles have been postulated to play a vital role in the reactivation of viruses from latency. Cytokines regulate gene expression by activating transcription factors via well-characterized signal transduction pathways. In this study, we report the identification of a novel inducible protein, GBP-i, that binds to a double-stranded GGA/C-rich region of the transcriptional control region of the human papovavirus JC virus (JCV), specifically within the origin of viral DNA replication. GBP-i is distinct from previously characterized GC-box-binding proteins with respect to both its sequence specificity and its electrophoretic mobility on native and denaturing gels. GBP-i responds within 90 min to phorbol myristate acetate stimulation; however, unlike typical phorbol myristate acetate-inducible factors, this rapid induction is regulated primarily at the transcriptional level. Further, the induction of GBP-i appears to be widespread and mediated by many inflammatory cytokines, including interleukin-1 beta, tumor necrosis factor alpha, gamma interferon, and transforming growth factor beta. Interestingly, the induced protein acts as a transcriptional repressor in its native context in the JCVL promoter. However, when its binding sequence is transposed to a heterologous promoter, GBP-i appears to function as a transcriptional activator. The data presented here suggest a role for GBP-i in cytokine-mediated induction of viral and cellular genes.

p53 and proliferating cell nuclear antigen expression in JC virus-infected cells of progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML), a demyelinating disease of the central nervous system (CNS) caused by infection with JC papova virus (JCV), is characterized by marked atypical changes in the glial cells. The JCV T protein binds cellular p53 (a tumor suppressor gene product), which as a result loses its normal down regulating influence on the cell cycle. We hypothesized that this binding would stabilize p53 and prolong its half life, leading to its immunohistochemical detection. To prove our theory combined JCV DNA:DNA in situ hybridization (ISH) and glial fibrillary acidic protein (GFAP) immunohistochemistry (IHC) as well as p53/GFAP double IHC were performed on routinely processed sections of five brains obtained at autopsy and two cerebral biopsy specimens from seven patients with PML. All specimens showed JCV infected oligodendrocytes and bizarre looking astrocytes that immunostained strongly for p53. In addition, because loss of p53 function results in proliferating cell nuclear antigen (PCNA) overexpression PCNA/GFAP double IHC was carried out, and a positive immunoreaction was obtained in JCV infected cells in the two biopsy specimens. The evidence of p53 immunoreactivity in JCV harboring glial cells seems to indicate a link between the JCV induced stabilization/inactivation of p53 and the striking tumorlike glial changes seen in PML. Proliferating cell nuclear antigen overexpression in these cells further supports this pathogenetic construct.

Identification and characterization of a novel GGA/C-binding protein, GBP-i, that is rapidly inducible by cytokines

Immunosuppressive states with accompanying alterations in cytokine profiles have been postulated to play a vital role in the reactivation of viruses from latency. Cytokines regulate gene expression by activating transcription factors via well-characterized signal transduction pathways. In this study, we report the identification of a novel inducible protein, GBP-i, that binds to a double-stranded GGA/C-rich region of the transcriptional control region of the human papovavirus JC virus (JCV), specifically within the origin of viral DNA replication. GBP-i is distinct from previously characterized GC-box-binding proteins with respect to both its sequence specificity and its electrophoretic mobility on native and denaturing gels. GBP-i responds within 90 min to phorbol myristate acetate stimulation; however, unlike typical phorbol myristate acetate-inducible factors, this rapid induction is regulated primarily at the transcriptional level. Further, the induction of GBP-i appears to be widespread and mediated by many inflammatory cytokines, including interleukin-1 beta, tumor necrosis factor alpha, gamma interferon, and transforming growth factor beta. Interestingly, the induced protein acts as a transcriptional repressor in its native context in the JCVL promoter. However, when its binding sequence is transposed to a heterologous promoter, GBP-i appears to function as a transcriptional activator. The data presented here suggest a role for GBP-i in cytokine-mediated induction of viral and cellular genes.

AIDS presenting as progressive multifocal leukoencephalopathy with clinical response to zidovudine

Progressive multifocal leukoencephalopathy (PML) due to JC virus can be the initial manifestation of AIDS. A 40-year-old man seropositive for HIV-1 presented with aphasia, hemiparesis, and hemianopsia, and with magnetic resonance imaging of the brain typical of PML. He quickly became bed bound, incontinent, and mute. The diagnosis of PML was established by histopathology in a brain biopsy with positive immunocytochemistry for polyomavirus capsid proteins, and detection of JCV DNA by polymerase chain reaction using JCV-specific primers. High dose zidovudine therapy was initiated (1200 mg/day). Within two weeks the patient began to respond, and after three months he was able to walk and care for himself and was discharged. He lived for two years from the onset of PML. While cytarabine has been the drug most widely used for PML treatment, this is the second confirmed case with apparent response to zidovudine. High dose zidovudine may benefit some previously untreated AIDS patients with onset as PML.

Transcription of a human neurotropic virus promoter in glial cells: effect of YB-1 on expression of the JC virus late gene

We have isolated a partial recombinant cDNA clone from a HeLa expression library which encodes a protein capable of binding to the central region of the human neurotropic JC virus (JCV) enhancer/promoter, termed the B region. Sequence analysis revealed a complete homology of the partial cDNA clone to the N-terminal region, of a previously described DNA-binding protein, termed YB-1. Band shift analyses have indicated that the bacterially produced YB-1 interacts specifically with the double-stranded B oligonucleotide as well as the corresponding single-stranded DNA fragment representing the early promoter sequence. Further analysis indicated that the YB-1 protein binds specifically to the C/T-rich sequence of the B domain, which is located in close proximity to the TATA box within the virus enhancer/promoter. Results from cotransfection experiments demonstrated that the full-length (YB-1) but not the partial cDNA enhances expression of the JCV late (JCVL) promoter in glial cells. Cointroduction into glial cells of a recombinant expressing the YB-1 and JCVL deletion mutants indicated that removal of the C/T-rich sequence of the B domain reduces the level of activation of the virus promoter by YB-1. Further cotransfection experiments revealed that the virus transactivating protein T antigen appears to diminish the ability of YB-1 to activate JCVL gene expression. RNA studies indicated that YB-1 is expressed in several cell types and tissues. Examination of YB-1 RNA from mouse brain at various stages of development revealed high levels of YB-1 RNA at early stages of development and lower levels at all subsequent developmental stages.

The role of a pentanucleotide repeat sequence, AGGGAAGGGA, in the regulation of JC virus DNA replication

The human polyomavirus JCV differs from other papovaviruses in its narrow host range and tissue tropism for human glial cells. It is believed that the cell-specific tropism of JCV to glial cells rests, at least in part, in transcription of the viral early gene that encodes the large tumor antigen (T-antigen). The secondary stage, however, which restricts the replication cycle of JCV to primate cells, is controlled at the level of viral DNA replication. In this study, we demonstrate that a cis-acting transcription regulatory element encompassing the pentanucleotide repeat sequence AGGGAAGGGA (penta), which is located in close proximity to the origin of DNA replication, plays an important role in the replication of viral DNA mediated by the JCV T-antigen, but not T-antigen derived from SV40. Analysis of DNA structure by diethyl pyrocarbonate (DEPC) has revealed that mutations within the penta which affect DNA replication also alter the structure of the neighboring A+T-rich region. These results suggest that, in addition to the regulatory role in viral gene expression, the penta may function as a DNA structural element which is important for JCV DNA replication mediated by the JCV T-antigen.

Differential expression of mRNAs for JC virus large and small tumor antigens in brain tissues from progressive multifocal leukoencephalopathy patients with and without AIDS

JC virus (JCV) causes progressive multifocal leukoencephalopathy (PML), the fatal demyelinating infection of oligodendrocytes, in up to 5% of AIDS patients. An intron-differential RNA PCR was developed to study the expression of alternately spliced JCV early mRNAs in brain tissues from PML patients with and without AIDS and in JCV-induced hamster brain tumors. The method utilizes primers that span the large tumor (T) and small tumor (t) antigen introns allowing amplification of specific cDNAs in the presence of contaminating viral genomic DNA. Hybridization with specific junctional probes and DNA sequence analysis confirmed the identity of the PCR products. Sequencing showed that JCV early mRNA is alternatively spliced as previously predicted by analogy to simian virus 40. Large T antigen mRNA was detected in all the brain tissues from PML patients with and without AIDS. The expression of small t antigen mRNA varied depending upon the association of PML with AIDS and upon other unknown factors. Of the 12 PML/AIDS brain tissue samples, 11 (92%) expressed small t antigen mRNA, whereas only 8 of 13 (62%) brain samples from patients with PML alone showed detectable levels of small t antigen mRNA. Human immunodeficiency virus 1 proviral DNA was detected in 10 of 12 PML/AIDS brain samples. The results indicate that alternative splicing of JCV early mRNA is regulated in the human brain and that the production of small t antigen may not be essential for the pathogenesis of PML.

The POU domain protein Tst-1 and papovaviral large tumor antigen function synergistically to stimulate glia-specific gene expression of JC virus

Synergism between transcriptional activators is a powerful way of potentiating their function. Here we show that the glial POU domain protein Tst-1 (also known as Oct-6 and SCIP) and large tumor antigen (T antigen) synergistically increased transcription from both the early and the late promoters of papovavirus JC in glial cells. Synergism between both proteins did not require T-antigen-mediated DNA replication or direct binding of T antigen to the promoter. The ability of T antigen to functionally cooperate with Tst-1 was contained within its N-terminal region, shown by the fact that small tumor antigen (t antigen) could substitute for T antigen in transfection experiments. In addition to this functional synergism, a direct interaction between Tst-1 and T antigen was observed in vitro. Using deletion mutants of Tst-1 and T antigen, the POU domain of Tst-1 and the N-terminal region of T antigen were found to participate in this interaction. Because of the low levels of Tst-1 present in oligodendrocytes, synergism between Tst-1 and T antigen could be an important factor in establishing the lytic infection of oligodendrocytes by JC virus during the course of the fatal demyelinating disease progressive multifocal leukoencephalopathy.

Nested PCR for detection of BK virus and JC virus DNA

BACKGROUND

A nested polymerase chain reaction (PCR) was developed to detect BK virus (BKV) and JC virus (JCV) DNA sequences. The unique clevage site for BamHI restriction enzyme was located in the JCV amplimer and cleavage was used to differentiate between BKV and JCV.

STUDY DESIGN

Twenty-three urine specimens from 17 bone marrow recipients with haemorrhagic cystitis and one liver transplant patient were tested for the presence of BKV and JCV DNA. Four brain tissue specimens (paraffin embedded brain tissues and a fresh frozen brain biopsy) and 5 cerebrospinal fluids from 3 AIDS patients and one liver transplant patient, all with progressive multifocal leukoencephalopathy (PML), were also examined by PCR.

RESULTS

The sensitivity of the PCR was 10 genomes for each virus. BKV DNA was detected in 15 urine specimens from 12 bone marrow transplant patients. JCV DNA was detected in 4 cerebrospinal fluids and 4 brain tissues from patients with PML.

CONCLUSION

Our results show that the nested PCR is a sensitive and rapid assay that can be used for diagnosis of BKV and JCV infections. The cerebrospinal fluid appears to be a suitable material for diagnosis of JC virus reactivation in the brain.

Nested PCR for detection of BK virus and JC virus DNA

BACKGROUND

A nested polymerase chain reaction (PCR) was developed to detect BK virus (BKV) and JC virus (JCV) DNA sequences. The unique clevage site for BamHI restriction enzyme was located in teh JCV amplimer and cleavage was used to differentiate between BKV and JCV.

STUDY DESIGN

Twenty-three urine specimens from 17 bone marrow recipients with haemorrhagic cystitis and one liver transplant patient were tested for the presence of BKV and JCV DNA. Four brain tissue specimens (paraffin embedded brain tissues and a fresh frozen brain biopsy) and 5 cerebrospinal fluids from 3 AIDS patients and one liver transplant patient, all with progressive multifocal leukoencephalopathy (PML), were also examined by PCR.

RESULTS

The sensitivity of the PCR was 10 genomes for each virus. BKV DNA was detected in 15 urine specimens from 12 bone marrow transplant patients. JCV DNA was detected in 4 cerebrospinal fluids and 4 brain tissues from patients with PML.

CONCLUSION

Our results show that the nested PCR is a sensitive and rapid assay that can be used for diagnosis of BKV and JCV infections.

SV40 large T antigen with c-Jun down-regulates myelin P0 gene expression: a mechanism for papovaviral T antigen-mediated demyelination

Expression of myelin proteins has been shown to be altered in transgenic mice that express papovaviral large tumor (T) antigens. This paper analyzes the effect on P0 gene expression in secondary Schwann cells transfected with the SV40 T antigen gene and in Schwann cells immortalized by T antigen. In secondary Schwann cells, both T antigen and c-Jun are required for significant inhibition of the P0 promoter; expression of only one of the proteins is insufficient for repression of the P0 gene. T antigen, c-Jun (p39), and c-Jun-related protein (p47) form an immunoprecipitable complex in SV40 immortalized Schwann cell lines, and T antigen and c-Jun bind independently and as a complex to the P0 promoter. Our data suggest that the probable molecular mechanism underlying the hypomyelination observed in transgenic animals expressing T antigen may be due to the repression of the P0 gene by T antigen and c-Jun.

Regulation of JC virus expression in B lymphocytes

The etiologic agent of progressive multifocal leukoencephalopathy, a subacute demyelinating disease of the central nervous system, is the human polyomavirus JC virus (JCV), which causes a lytic infection of myelin-producing oligodendrocytes. In infected individuals the JCV genome can be detected in brain tissue and B lymphocytes isolated from the blood, bone marrow, or lymph nodes. Using mobility shift assays and a radiolabeled oligonucleotide from the JCV promoter-enhancer region (JCV bp 130 to 160), referred to as domain B, we were able to detect specific bands of the same mobility in nuclear extracts from human fetal glial cells, U-251 glioma cells, different B-cell lines, and in vitro-activated tonsillar B lymphocytes but not from T cells. In addition, a specific shift was detected when using nuclear extracts from freshly isolated tonsillar or lymph node B cells from five AIDS patients, two of whom later developed progressive multifocal leukoencephalopathy. Somewhat surprisingly, the above gel shift was partially inhibited by unlabeled oligonucleotides containing a kappa E2-binding site. UV cross-linking of the protein-DNA complex from either B cells or glial cells and analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of a 46-kDa band. Transient transfection of a reporter plasmid constructed by fusing a trimer of the domain B sequence to a minimal promoter revealed activity in B lymphocytes and glial cells but not in T cells. Mutational analysis of this region demonstrated that the core TGGC repeat was essential for enhancer activity. Thus, a similar protein in B lymphocytes and glial cells may account for the preferential replication of JCV in these two cell types.

Ultrastructural studies in the lytic phase of progressive multifocal leukoencephalopathy in AIDS patients

Brain fragments from eight cases (four autopsies and four biopsies) of patients with acquired immune deficiency syndrome (AIDS) with JC virus (JCV) lytic infections were examined ultrastructurally. Particular efforts were made to look for virions and their subcellular distribution in cells not usually involved by papovavirus infection. The cellular and subcellular distribution of virions was investigated with emphasis on cell types not normally associated with papovavirus infection. The pattern of JCV infection was as follows: 1) oligodendrocytes; nucleus only, 7 cases; cytoplasm only, no cases; 2) astrocytes (normal and "bizarre"); nucleus and cytoplasm, two cases; cytoplasm only, four cases; 3) macrophages; nucleus and cytoplasm, one case; cytoplasm only, four cases; and 4) neurons; nucleus and cytoplasm, two cases; cytoplasm only, three cases. Perivascular, endothelial, ependymal, and microglial cells were never infected. Our ultrastructural data indicate that cell types other than oligodendrocytes can be involved productively by JCV in the lytic phase of progressive multifocal leukoencephalopathy (PML) in AIDS patients. Neuronal cells, especially, can be infected productively by the JCV, and this should be considered in clinical interpretation of cortical symptoms and signs in suspected or proven cases of PML.

Cellular changes in the cerebellar granular layer in AIDS-associated PML

Six cases of AIDS-associated progressive multifocal leukoencephalopathy (PML) exhibited peculiar cellular changes in the cerebellar granular layer. These cells without discernible cytoplasm showed hypochromatic nuclei about twice as large as those of normal granule cells. They were restricted exclusively to the granular layer and always surrounded PML foci. An astrocytic, leukocytic or macrophage/microglial nature was largely excluded by immunocytochemistry. Human immunodeficiency virus (HIV) antigen p 24 could not be found in these cells and there was no unequivocal detection of JC virus (JCV) DNA and no ultrastructural evidence of papovavirus particles in them. They possibly represent altered cerebellar granule cells abortively or latently infected with JCV.

Human immunodeficiency virus type 1 infection of the brain

Direct infection of the central nervous system by human immunodeficiency virus type 1 (HIV-1), the causative agent of AIDS, was not appreciated in the early years of the AIDS epidemic. Neurological complications associated with AIDS were largely attributed to opportunistic infections that arose as a result of the immunocompromised state of the patient and to depression. In 1985, several groups succeeded in isolating HIV-1 directly from brain tissue. Also that year, the viral genome was completely sequenced, and HIV-1 was found to belong to a neurotropic subfamily of retrovirus known as the Lentivirinae. These findings clearly indicated that direct HIV-1 infection of the central nervous system played a role in the development of AIDS-related neurological disease. This review summarizes the clinical manifestations of HIV-1 infection of the central nervous system and the related neuropathology, the tropism of HIV-1 for specific cell types both within and outside of the nervous system, the possible mechanisms by which HIV-1 damages the nervous system, and the current strategies for diagnosis and treatment of HIV-1-associated neuropathology.

Polyomavirus models of brain infection and the pathogenesis of multiple sclerosis

Multiple sclerosis (MS) is generally considered to be an autoimmune disorder with myelin as the target and with several unidentified viruses playing ancillary roles, possibly through molecular mimicry. Although this paradigm has led to important progress on potential mechanisms of myelin loss, neither a target antigen in myelin nor a triggering mechanism has yet been identified, leaving the etiology of MS still unknown. Animal models of viral demyelination and studies showing that JC virus (JCV), the polyomavirus which causes progressive multifocal leukoencephalopathy (PML), may be latent in some normal human brains suggest another possibility. A host immune response targeting proteins expressed at low levels from viral DNA latent in the central nervous system (CNS) might underlie a focal demyelinating disease such as MS. A shift from autoimmunity to a latent-virus model is not a trivial substitution of target antigens. This shift would expand the search for a definitive laboratory test for MS and could lead to improved therapeutic and preventive approaches.

Regulation of JC virus by the POU-domain transcription factor Tst-1: implications for progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy results from an opportunistic infection of myelin-producing oligodendrocytes by the glia-specific human papovavirus JC. In this report, evidence is presented that the glial transcription factor Tst-1, a member of the POU-domain family, stimulates transcription of both early and late viral genes. Stimulation was dependent on site-specific binding of Tst-1 to the JC viral regulatory region and on the presence of an intact amino-terminal transactivation domain within Tst-1. Because of its ability to increase the expression of viral large tumor antigen, Tst-1 stimulated viral DNA replication, without participating directly in the replication event. Our results suggest that Tst-1 is one of the determining factors in the glia specificity of JC virus.

The transcriptional enhancer element, kappa B, regulates promoter activity of the human neurotropic virus, JCV, in cells derived from the CNS

Studies on the regulation of the human neurotropic virus (JCV) promoter, have been focused primarily on the 98 bp tandem repeat sequence which confers glial-specificity to viral gene expression. We demonstrate that a distinct regulatory element outside of the 98 bp region, which spans a stretch of 10 nucleotides (nt) (5'-GGGAATTTCC-3') increases transcriptional activity of JCV late (JCVL), and early (JCVE) promoters in glial cells. Sequence analysis of this motif reveals extensive homology to the kappa B sequence of HIV-1 (5'-GGGACTTTCC-3'). A DNA fragment corresponding to the 10 nt sequence of JCV exhibits transcriptional activity when placed upstream of the test promoter in glial cells. The induction mediated by this regulatory motif is moderately enhanced in response to phorbol 12-myristate 13-acetate (PMA) in glial cells. Band-shift and UV-crosslinking experiments suggest that glial cells constitutively produce proteins that specifically interact with the JCV kappa B, but not the HIV-1 kappa B motif. Treatment of cells with PMA results in formation of new complexes that are sensitive to the kappa B sequences derived from the JCV and HIV-1 genomes. These results suggest that the kappa B sequence located in the JCV genome may play a role in transcriptional regulation of JCV gene expression by interacting with inducible and uninducible nuclear proteins from glial cells.

Tri-primer PCR can distinguish free and cloned viral DNA in a single reaction

A polymerase chain reaction based method is described which distinguishes free and cloned JC virus (JCV) DNA in a single reaction. The method utilizes three primers and amplifies DNA fragments of two different sizes, one specific for free and another specific for pBR322 cloned viral DNA. The procedure was used to simultaneously detect the presence of free and contaminating cloned JCV DNA in brain tissues.

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.

Interaction of the human polyomavirus, JCV, with human B-lymphocytes

The human polyomavirus, JCV, is the causative agent of the central nervous system demyelinating disease progressive multifocal leukoencephalopathy (PML). The principal target of JCV infection in the central nervous system (CNS) is the myelinating oligodendrocyte. However, the site of JCV multiplication outside of the CNS and the mechanism by which virus gains access to the brain are not known. Recently, JCV infected B-lymphocytes have been demonstrated in PML patients in several lymphoid organs, in circulating peripheral lymphocytes, and in brain, suggesting a possible role of B-lymphocytes in the dissemination of virus to the brain. The experiments reported here were undertaken to understand more about the interactions of JCV with human B-lymphocytes. The data show that JCV is able to multiply in either Epstein-Barr virus transformed (EBV) or EBV negative human B cell lines resulting in production of infectious, progeny virions. In addition, nuclear proteins extracted from these B cells bind to similar nucleotides within the JCV regulatory region that are bound by nuclear proteins extracted from human fetal glial cells, the most susceptible host and principal target cell for JCV infection in vitro. It is not known, however, whether these DNA binding proteins from susceptible B cells and glial cells are similar.

Detection of JC virus DNA in peripheral lymphocytes from patients with and without progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) results from lytic infection of oligodendrocytes by JC virus (JCV). Although JCV has been identified in mononuclear cells in bone marrow and hematogenous dissemination of the virus to the central nervous system has been suspected, JCV has never been clearly demonstrated in the peripheral circulation. Using polymerase chain reaction technology, we examined peripheral lymphocytes of 19 patients with brain biopsy-proven PML for the JCV genome. Two non-PML control groups, consisting of 26 patients seopositive for human immunodeficiency virus type 1 (HIV-1) and 30 immunocompetent patients with Parkinson's disease, were also examined for the presence of the JCV genome in lymphocytes. Cerebrospinal fluid from 10 patients with PML was examined for the presence of the JCV genome as well. The JCV genome was detected in the lymphocytes of 89% (17) of the patients with PML, 38% (10) of the HIV-1-seropositive patients without PML, and none of the patients with Parkinson's disease. Sequencing of the JCV regulatory region from the lymphocytes of three patients revealed the prototype MAD-1 strain of JCV in one patient with PML, a MAD-4 strain in a second patient with PML, and a slightly modified MAD-4 strain in an HIV-1-positive patient without PML. Only 3 of 10 patients with PML who had JCV detected in lymphocytes had the JCV genome in their cerebrospinal fluid. These results demonstrate that the JCV genome can be found in circulating lymphocytes from patients with PML and suggest that lymphocytes are an important vector for hematogenous dissemination of JCV to the central nervous system.(ABSTRACT TRUNCATED AT 250 WORDS)