Persistence of DNA sequences of BK virus and JC virus in normal human tissues and in diseased tissues

Human polyoma virus in renal allograft biopsies: morphological findings and correlation with urine cytology

Human polyoma virus (PV) interstitial nephritis occurs in immunosuppressed patients after reactivation of latent virus in renal epithelium. Currently, there is neither general consensus about the incidence of clinically significant PV infection in renal transplants nor conclusive evidence determining its significance in the long-term graft outcome. We evaluated 601 renal transplant biopsy specimens (from 365 patients) by routine light microscopy and immunoperoxidase stains with antibody against SV40 (which cross reacts with PV). We also examined urine samples from 200 patients (100 obtained concurrently with a renal biopsy in patients presenting with acute graft dysfunction and 100 from patients with stable graft function). Electron microscopic evaluation was performed in 50 renal biopsy specimens and in 23% of all urine samples. PV was identified in 1.8% biopsy specimens (1.9% of patients). PV interstitial nephritis showed the typical viral cytopathic changes in tubular epithelial cells associated with marked tubular damage and a disproportionately mild degree of tubulitis. There was no difference in the incidence of PV in the urine of patients with acutely deteriorating versus stable renal function (18% and 19%, respectively); however, urines with large numbers of infected cells (> 10/cytospin) and inflammatory changes in the sediments corresponded invariably to patients with acute allograft dysfunction (8 of 8), and in most cases to biopsy specimens showing PV interstitial nephritis (7 of 8). Based on these findings, urine samples seem to be the most sensitive and cost-effective screening method for PV infection; only urine samples with inflamed sediments and abundant infected cells correlate with clinically significant disease. In these cases, examination of a renal biopsy is indicated. Immunohistochemical stains are useful to confirm the presence of PV but do not increase the sensitivity of diagnosis of PV if this is not already suspected on routine light microscopy. In our material, immunostains were helpful ruling out the presence of PV in a small number of biopsy specimens (2%) that showed markedly reactive tubular cells resembling PV infection. Most patients with PV interstitial nephritis responded to decreased immunosuppression; however, the decay in graft function (based on creatinine slopes) was significantly more rapid in these patients than in matched controls. Evidence of PV infection should be systematically sought in renal biopsy specimens and urine samples from renal allograft recipients.

[Progressive multifocal leukoencephalopathy]

PATHOGENESIS

Progressive multifocal leukoencephalopathy is a demyelinating disease of the central nervous system caused by infection and reactivation of JC-virus. About 5% of all HIV-infected patients develop this fatal disease. Although pathogenesis is not completely understood, progressive multifocal leukoencephalopathy is thought to be a persistent infection. The kidneys, bone marrow, peripheral blood lymphocytes and the brain itself are candidates for latency sites of JC-virus. Loss of T-helper-cells in the course of HIV-infection or other immunosuppressive states result in reactivation of JC-virus.

DIAGNOSIS

Progressive multifocal leukoencephalopathy can be diagnosed by focal neurological symptoms, radiographic signs in magnetic resonance imaging and detection of JC-virus in brain tissue or cerebrospinal fluid.

TREATMENT

A specific therapy is not yet available or established. Highly active antiretroviral therapy (HAART) and cidofovir are promising and may prove useful in the near future.

Polyomavirus infection of renal allograft recipients: from latent infection to manifest disease

Polyomavirus (PV) exceptionally causes a morphologically manifest renal allograft infection. Five such cases were encountered in this study, and were followed between 40 and 330 d during persistent PV renal allograft infection. Transplant (Tx) control groups without PV graft infection were analyzed for comparison. Tissue and urine samples were evaluated by light microscopy, immunohistochemistry, electron microscopy, and PCR. The initial diagnosis of PV infection with the BK strain was made in biopsies 9+/-2 mo (mean +/- SD) post-Tx after prior rejection episodes and rescue therapy with tacrolimus. All subsequent biopsies showed persistent PV infection. Intranuclear viral inclusion bodies in epithelial cells along the entire nephron and the transitional cell layer were histologic hallmarks of infection. Affected tubular cells were enlarged and often necrotic. In two patients, small glomerular crescents were found. In 54% of biopsies, infection was associated with pronounced inflammation, which had features of cellular rejection. All patients were excreting PV-infected cells in the urine. PV infection was associated with 40% graft loss (2 of 5) and a serum creatinine of 484+/-326 micromol/L (mean +/- SD; 11 mo post-Tx). Tx control groups showed PV-infected cells in the urine in 5%. Control subjects had fewer rejection episodes (P<0.05) and stable graft function (P = 0.01). It is concluded that a manifest renal allograft infection with PV (BK strain) can persist in heavily immunosuppressed patients with recurrent rejection episodes. PV mainly affects tubular cells and causes necrosis, a major reason for functional deterioration. A biopsy is required for diagnosis. Urine cytology can serve as an adjunct diagnostic tool.

Immunohistochemical detection of JC virus in nontumorous renal tissue of a patient with renal cancer but without progressive multifocal leukoencephalopathy

We performed immunohistochemical staining on the nontumorous renal tissue of 45 patients with renal cancer but without progressive multifocal encephalopathy using JCV-specific antibody. For one patient we found positive staining of the nuclei of the renal collecting ducts. Immunoelectron microscopic examination of the positive cell nuclei revealed electron-dense polyomavirus-like particles.

Reciprocal interaction between two cellular proteins, Puralpha and YB-1, modulates transcriptional activity of JCVCY in glial cells

Cross communication between regulatory proteins is an important event in the control of eukaryotic gene transcription. Here we have examined the structural and functional interaction between two cellular regulatory proteins, YB-1 and Puralpha, on the 23-bp sequence element derived from the enhancer-promoter of the human polyomavirus JCV. YB-1 and Puralpha are single-stranded DNA binding proteins which recognize C/T- and GC/GA-rich sequences, respectively. Results from band shift studies demonstrated that while both proteins interact directly with their DNA target sequences within the 23-bp motif, each protein can regulate the association of the other one with the DNA. Affinity chromatography and coimmunoprecipitation provide evidence for a direct interaction between Puralpha and YB-1 in the absence of the DNA sequence. Ectopic expression of YB-1 and Puralpha in glial cells synergistically stimulated viral promoter activity via the 23-bp sequence element. Results from mutational studies revealed that residues between amino acids 75 and 203 of YB-1 and between amino acids 85 and 215 of Puralpha are important for the interaction between these two proteins. Functional studies with glial cells indicated that the region within Puralpha which mediates its association with YB-1 and binding to the 23-bp sequence is important for the observed activation of the JCV promoter by the Puralpha and YB-1 proteins. The results of this study suggest that the cooperative interaction between YB-1 and Puralpha mediates the synergistic activation of the human polyomavirus JCV genome by these cellular proteins. The importance of these findings for cellular and viral genes which are regulated by Puralpha and YB-1 is discussed.

Polyomavirus disease under new immunosuppressive drugs: a cause of renal graft dysfunction and graft loss

BACKGROUND

Manifest polyomavirus (PV) renal graft infection is a rare complication. We diagnosed 5 cases among 70 kidney recipients undergoing transplants since December 1995; however, there were no cases at our institution before December 1995.

METHOD

To identify risk factors promoting manifest PV graft infection, we compared those 5 patients with kidney recipients who had signs of PV replication but no manifest graft infection (n=23, control group). PV replication was judged by the presence of intranuclear inclusion cells in the urine.

RESULTS

Before the infection, five of five patients had recurrent rejection episodes. All were switched from cyclosporine A to high dose tacrolimus as rescue therapy. Infection was diagnosed histologically 9+/-2 months posttransplantation; it persisted and led to graft loss in four of five patients. In control patients, graft function was stable, 1 of 23 patients were switched to tacrolimus as rescue therapy, and graft loss occurred in 4 of 23 patients.

CONCLUSION

Recurrent rejection episodes and high dose immunosuppressive therapy, including tacrolimus, are risk factors for manifest PV kidney graft infection, which has an ominous prognosis.

Dual qualitative-quantitative nested PCR for detection of JC virus in cerebrospinal fluid: high potential for evaluation and monitoring of progressive multifocal leukoencephalopathy in AIDS patients receiving highly active antiretroviral therapy

JC polyomavirus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a central nervous system infection that mainly affects AIDS patients. The extensive application of highly active antiretroviral therapy (HAART) is leading to the appearance of "long-term" survival PML patients. A reliable and feasible qualitative-quantitative test for both the detection of JCV and follow-up of its viral burden in this emerging group of patients is clearly required. With this aim, a dual qualitative-quantitative nested PCR is presented in this study for the analysis of JCV DNA in cerebrospinal fluid (CSF). Two newly designed internal controls, one competitive and the other noncompetitive, have been constructed to adapt this PCR to either measure the JCV burden or to allow a highly confident determination of JCV presence or clearance. The analytical sensitivity of the technique allows the detection of 0.01 fg (three genomes) of JCV DNA. Its qualitative application has been evaluated by analyzing single CSF samples from a group of 17 patients with PML and a control group of 20 patients with diverse neurological conditions other than PML, yielding sensitivity and specificity values of 100 and 90%, respectively. The quantitative application has been evaluated in vitro in blind tests with samples including serial dilutions of JCV, and in all cases the samples were successfully ordered considering the JCV titer. The dual quantitative-qualitative application offered by this nested PCR may provide an answer to the new requirements for evaluating and finely monitoring PML in AIDS patients receiving HAART.

Association of simian virus 40 with a central nervous system lesion distinct from progressive multifocal leukoencephalopathy in macaques with AIDS

The primate polyomavirus SV40 is known to cause interstitial nephritis in primary infections and progressive multifocal leukoencephalopathy (PML) upon reactivation of a latent infection in SIV-infected macaques. We now describe a second central nervous system manifestation of SV40: a meningoencephalitis affecting cerebral gray matter, without demyelination, distinct from PML. Meningoencephalitis appears also to be a primary manifestation of SV40 infection and can be seen in conjunction with SV40-induced interstitial nephritis and pneumonitis. The difference in the lesions of meningoencephalitis and PML does not appear to be due to cellular tropism, as both oligodendrocytes and astrocytes are infected in PML and meningoencephalitis, as determined by in situ hybridization or immunohistochemistry for SV40 coupled with immunohistochemistry for cellular determinants. This is further supported by examination of SV40 nucleic acid sequences from the ori-enhancer and large-T-antigen regions, which reveals no tissue-or lesion-specific variation in SV40 sequences.

Detection of JC virus DNA in human tonsil tissue: evidence for site of initial viral infection

Progressive multifocal leukoencephalopathy is a demyelinating disease of the human central nervous system that results from lytic infection of oligodendrocytes by the polyomavirus JC (JCV). Originally, JCV was thought to replicate exclusively in human glial cells, specifically oligodendrocytes. However, we have recently shown that JCV can replicate in cells of lymphoid origin such as hematopoietic precursor cells, B lymphocytes, and tonsillar stromal cells. To determine whether tonsils harbor JCV, we tested a total of 54 tonsils, 38 from children and 16 from adult donors. Nested PCRs with primer sets specific for the viral T protein and regulatory regions were used for the detection of JCV DNA. JCV DNA was detected in 21 of 54 tonsil tissues, or 39% (15 of 38 children and 6 of 16 adults) by using regulatory-region primers and in 19 of 54 tonsil tissues, or 35% (13 of 38 children and 6 of 16 adults) by using the T-protein primers. The DNA extracted from children's nondissected tonsil tissue, isolated tonsillar lymphocytes, and isolated stromal cells that demonstrated PCR amplification of the JCV regulatory region underwent cloning and nucleotide sequencing. Of the regulatory-region sequences obtained, nearly all contained tandem repeat arrangements. Clones originating from nondissected tonsil tissue and tonsillar lymphocytes were found to have sequences predominantly of the Mad-1 prototype strain, whereas the majority of clones from the DNA of tonsillar stromal cells had sequences characteristic of the Mad-8br strain of JCV. A few clones demonstrated structures other than tandem repeats but were isolated only from tonsillar lymphocytes. These data provide the first evidence of the JCV genome in tonsil tissue and suggest that tonsils may serve as an initial site of viral infection.

Archetype JC virus efficiently replicates in COS-7 cells, simian cells constitutively expressing simian virus 40 T antigen

JC polyomavirus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), is ubiquitous in humans, infecting children asymptomatically and then persisting in the kidney. Renal JCV is not latent but replicates to excrete progeny in the urine. The renal-urinary JCV DNAs carry the archetype regulatory region that generates various rearranged regulatory regions occurring in JCVs derived from the brains of PML patients. Tissue cultures that support the efficient growth of archetype JCV have not been reported. We studied whether archetype JCV could replicate in COS-7 cells, simian cells transformed with an origin-defective mutant of simian virus 40 (SV40). Efficient JCV replication, as detected by a hemagglutination assay, was observed in cultures transfected with five of the six archetype DNAs. The progeny JCVs could be passaged to fresh COS-7 cells. However, when the parental cells of COS-7 not expressing T antigen were transfected with archetype JCV DNAs, no viral replication was detected, indicating that SV40 T antigen is essential for the growth of JCV in COS-7 cells. The archetype regulatory region was conserved during viral growth in COS-7 cells, although a small proportion of JCV DNAs underwent rearrangements outside the regulatory region. We then attempted to recover archetype JCV from urine by viral culture in COS-7 cells. Efficient JCV production was observed in COS-7 cells infected with five of the six JCV-positive urine samples examined. Thus, COS-7 cells should be of use not only for the production of archetype JCV on a large scale but also for the isolation of archetype JCV from urine.

Tubulointerstitial nephritis due to a mutant polyomavirus BK virus strain, BKV(Cin), causing end-stage renal disease

A renal biopsy from a 36-year-old man with AIDS showed a severe tubulointerstitial nephritis with intranuclear inclusions in epithelial cells. Electron microscopy revealed the characteristic findings of a polyomavirus (PyV) infection, and immunofluorescence indicated the presence of BK virus (BKV) antigen. Inoculation of rhesus monkey kidney cell cultures both with urine and with buffy coat blood cells resulted in a cytopathic response which was subsequently confirmed to be due to BKV. Further characterization of the viral DNA from the kidney by PCR amplification and Southern blot analysis with PyV and strain-specific primers and probes indicated that the virus was closely related to the BK(Dun) strain but different in its apparent sequence arrangement. Subsequent cycle sequencing showed a dinucleotide mutation of TG-->AA which substitutes hydrophilic Gln for hydrophobic Leu in a sequence homologous to an origin DNA-binding domain of simian virus 40 T antigen. It is suggested that the mutation and a coding region rearrangement of this strain of BKV designated BKV(Cin) has the potential to alter viral DNA replication and enhance pathogenicity.

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.

Typing of urinary JC virus DNA offers a novel means of tracing human migrations

Although polyomavirus JC (JCV) is the proven pathogen of progressive multifocal leukoencephalopathy, the fatal demyelinating disease, this virus is ubiquitous as a usually harmless symbiote among human beings. JCV propagates in the adult kidney and excretes its progeny in urine, from which JCV DNA can readily be recovered. The main mode of transmission of JCV is from parents to children through long cohabitation. In this study, we collected a substantial number of urine samples from native inhabitants of 34 countries in Europe, Africa, and Asia. A 610-bp segment of JCV DNA was amplified from each urine sample, and its DNA sequence was determined. A worldwide phylogenetic tree subsequently constructed revealed the presence of nine subtypes including minor ones. Five subtypes (EU, Af2, B1, SC, and CY) occupied rather large territories that overlapped with each other at their boundaries. The entire Europe, northern Africa, and western Asia were the domain of EU, whereas the domain of Af2 included nearly all of Africa and southwestern Asia all the way to the northeastern edge of India. Partially overlapping domains in Asia were occupied by subtypes B1, SC, and CY. Of particular interest was the recovery of JCV subtypes in a pocket or pockets that were separated by great geographic distances from the main domains of those subtypes. Certain of these pockets can readily be explained by recent migrations of human populations carrying these subtypes. Overall, it appears that JCV genotyping promises to reveal previously unknown human migration routes: ancient as well as recent.

Comprehensive investigation of the presence of JC virus in AIDS patients with and without progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML), a viral-induced demyelinating disease, is becoming relatively common, while many diagnostic and pathogenetic aspects remain to be clarified. A study was therefore undertaken in 64 AIDS patients suffering from various neurological disorders, including PML (12 subjects), with the specific objective of searching for JC virus (JCV) DNA by nested PCR (n-PCR) in cerebrospinal fluid (CSF), peripheral blood mononuclear cells (PBMCs), and urine collected from all patients. CSF examination, CD4 and CD8 counts, neurological examinations, and neuroradiological investigations were undertaken. JCV DNA was detected in 92% of CSF specimens in 75% of the PBMCs and urine samples from the PML patients, whereas among the non-PML patients JCV DNA was not detected in any CSF samples, but was found in 10% of PBMCs and in 39% of the urine specimens. BKV and JCV DNA viruria was observed simultaneously in 6% of the AIDS patients without PML. The routine CSF tests including IgG oligoclonal bands, the Link, and Tourtellotte IgG indexes, did not show a typical pattern in PML cases. The data obtained clearly indicate that the detection of JCV DNA in CSF constitutes an efficient marker for PML diagnosis. The simultaneous presence of JCV DNA in the CSF, PBMCs, and urine samples from the PML patients, who did not differ from controls with regard to their immunosuppressive status, suggests that JCV could be carried into the central nervous system (CNS) by infected PBMCs.

Persistent JC virus (JCV) infection is demonstrated by continuous shedding of the same JCV strains

The polyomavirus JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy, is ubiquitous in the human population, infecting children asymptomatically. JCV is often detected in normal renal tissue and in the urine of healthy individuals. We demonstrate that renal JCV represents that which persists after primary infection.

High titers of antibodies to two human polyomaviruses, JCV and BKV, correlate with increased frequency of chromosomal damage in human lymphocytes

Associations of antibody titers to the JC and BK human polyoma viruses and the frequency of chromosome aberrations (CA) in human peripheral blood lymphocytes were studied. Study group consisted of 33 workers occupationally exposed to low doses of ionizing radiation and 11 control persons. There were no statistically significant differences in the JC and BK virus titer values between two groups of donors. It was found that JC and BK virus titers explained approximately 6% of total inter-individual variation in CA frequency. Such factors as alcohol abuse, age and, in this special group, exposure to ionizing radiation explained an additional 53% of the total variation in CA frequency. In six clean-up workers and one control, rogue cell (cells with multiple chromosome-type aberrations) were found. The incidence of rogue cells correlated significantly with JC and BK virus titers as well as a history of recent acute respiratory disease.

JC virus infection of hematopoietic progenitor cells, primary B lymphocytes, and tonsillar stromal cells: implications for viral latency

The human polyomavirus JC virus (JCV) infects myelin-producing cells in the central nervous system, resulting in the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). JCV-induced PML occurs most frequently in immunosuppressed individuals, with the highest incidence in human immunodeficiency type 1-infected patients, ranging between 4 and 6% of all AIDS cases. Although JCV targets a highly specialized cell in the central nervous system, infection is widespread, with more than 80% of the human population worldwide demonstrating serum antibodies. A number of clinical and laboratory studies have now linked the pathogenesis of PML with JCV infection in lymphoid cells. For example, JCV-infected lymphocytes have been suggested as possible carriers of virus to the brain following reactivation of a latent infection in lymphoid tissues. To further define the cellular tropism associated with JCV, we have attempted to infect immune system cells, including CD34+ hematopoietic progenitor cells derived from human fetal liver, primary human B lymphocytes, and human tonsillar stromal cells. Our results demonstrate that these cell types as well as a CD34+ human cell line, KG-1a, are susceptible to JCV infection. JCV cannot, however, infect KG-1, a CD34+ cell line which differentiates into a macrophage-like cell when treated with phorbol esters. In addition, peripheral blood B lymphocytes isolated by flow cytometry from a PML patient demonstrate JCV infection. These results provide direct evidence that JCV is not strictly neurotropic but can infect CD34+ hematopoietic progenitor cells and those cells which have differentiated into a lymphocytic, but not monocytic, lineage.

A simple method for detecting human polyomavirus DNA in urine by the polymerase chain reaction

In order to develop a simple and sensitive method for detecting human polyomavirus DNA in the urine of patients by the polymerase chain reaction (PCR), it was found that the viral DNA could be released from urine by proteinase K and then amplified by PCR directly, without additional treatment such as ultracentrifugation or DNA extraction. Direct PCR amplification of viral DNA from urine was volume limited and 5 microliters of urine appeared to be the optimum amount for direct PCR amplification. When the urine volume was greater than 10 microliters, the results of PCR were inconsistent. However, the urine volume could be increased after dialysis to remove possible inhibitor(s) which may interfere with PCR. Direct PCR amplification of patient urine is convenient and eliminates several steps which can cause loss of DNA from the sample.

Transcription of the JC virus archetype late genome: importance of the kappa B and the 23-base-pair motifs in late promoter activity in glial cells

The transcription control region of the archetype strain of the human polyomavirus JC virus (JCV(Cy)), unlike its neurotropic counterpart (JCV(Mad-1)), contains only one copy of the 98-bp enhancer/promoter repeat with the 23-bp and the 66-bp insertion blocks. Early studies by us and others have indicated that the structural organization of JCV(Mad-1) is critical for glial cell-specific transcription of the viral genome. In addition, the kappa B regulatory motif found in the JCV(Mad-1) genome, which also exists in JCV(Cy), confers inducibility to the JCV(Mad-1) early and late promoters in response to extracellular stimuli. In this study, we have investigated the regulatory role of the 23- and the 66-bp blocks and their functional relationship to the kappa B motif in stimulating transcription of the Cy early and late promoters in glial cells. We demonstrate that mutations in the kappa B motif reduce the basal activity of the Cy early promoter and decrease the levels of its induction by phorbol myristate acetate or factors derived from activated T cells. Under similar circumstances, mutation in the kappa B motif completely abrogated the basal and the induced levels of transcription of the viral late promoter. Using deletion and hybrid promoter constructs, we have demonstrated that the 23-bp block of the Cy promoter plays a critical role in the observed inactivation of Cy late promoter transcription in glial cells. Results from DNA binding studies have indicated the formation of a common nucleoprotein complex with the 23-bp sequence, mutant kappa B (kappa B(mut)), and wild-type kappa B (kappa B(wt)). Analysis of this complex by UV cross-linking has identified a 40-kDa protein which binds to the 23-bp sequence and the kappa B motif. The importance of these findings for the activation of JCV(Cy) under various physiological conditions is discussed.

Different genotypes of human polyomaviruses found in patients with autoimmune diseases in Taiwan

We have assayed for the presence of human polyomaviruses in urine of autoimmune disease patients, such as systemic lupus erythematosus (SLE), Sjogren's syndrome (SS), rheumatoid arthritis (RA), or dermatomyositis/polymositis (DM/PM), by PCR. The results indicate that approximately 40% of patients were JCV positive and 15% of the JCV positive patients were also infected by BKV at the same time according to Southern blot and DNA sequencing of the PCR products. Interestingly, the JCV present in autoimmune diseases patients were Taiwan-1, Taiwan-2, and Taiwan-3 strains with pentanucleotide-A (GGGAA) and/or -B (AAAGC) deletions within the regulatory region. In addition, BKV found in the examined samples were Taichung-1 and Taichung-2 strains. Taichung-1 had two nucleotide alterations and Taichung-2 had six nucleotide differences within the regulatory region when compared to WW BKV archetype. Although the examined autoimmune diseases patients included RA, SLE, PM, DM, and SS patients, there appears to be no correlation between disease and virus strains. However, Taiwan-2 strain JCV with two copies of pentanucleotide-A deletion was present in the patient with the longest period of immunosuppressive medication.

Genotypes of human polyomaviruses in urine samples of pregnant women in Taiwan

The viral DNA of human polyomaviruses JC virus (JCV) and BK virus (BKV) was detected by the polymerase chain reaction (PCR) in urine samples from 31 pregnant women in Taiwan. A pair of appropriate primers amplified both JCV and BKV DNA of the regulatory region simultaneously in PCR. An oligonucleotide probe homologous to both JCV and BKV regulatory region was used subsequently to detect the viral DNA by Southern blotting after PCR amplification. Approximately 36% of the examined urine samples were human polyomavirus positive. The genotypes of JCV and BKV were determined by DNA sequencing of their regulatory regions. Besides CY archetype, a new strain (Taiwan-1) of JCV with a pentanucleotide (GGGAA) deletion and a new strain (Taichung-1) of BKV with two nucleotide alterations within the regulatory region were found in the urine samples. Eight of the examined samples were JCV infected, one was BKV infected, and two were JCV and BKV mix-infected. The JCV positive individuals were infected by CY archetype and Taiwan-1 strain equally. However, Taichung-1 strain was the only BKV strain found in the BKV positive individuals.

PCR detection of JC virus DNA in brain tissue from patients with and without progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system, which is thought to be a result of the reactivation of JC virus (JCV), a human polyomavirus. The disease occurs in individuals with immunosuppression and in recent years there has been an increase in PML cases due to AIDS. A nested polymerase chain reaction (n-PCR) was employed to detect JCV and BK virus (BKV) DNA in brain tissue collected postmortem from 28 AIDS patients with PML and from 13 patients without PML, but with other diagnoses, including solid tumors, Alzheimer's disease, thromboembolism, myocardial infarction and acute cerebrovascular diseases. All 28 brain specimens from the patients with PML were positive for JCV DNA when tested by n-PCR and three of the latter were also positive for BKV DNA. These results were confirmed by an enzyme restriction analysis and a DNA hybridization assay. Interestingly, in this study, JCV DNA was also found in 6 brain tissue specimens from 4 subjects with diseases unrelated to PML or AIDS. All the brain specimens from the control group were negative for BKV DNA. The results confirm that the n-PCR is a useful tool for PML diagnosis. The presence of JCV DNA in the brain tissue of patients without PML is particularly important since it indicates that JCV could be latent in the brains of immunocompetent individuals. Moreover, detection of simultaneous presence of JCV and BKV in the brain tissue of the patients with PML demonstrates that BKV may also infect the human brain without causing any apparent neurological disease.

The JC virus antibody response in serum and cerebrospinal fluid in progressive multifocal leucoencephalopathy

BACKGROUND

A clinical diagnosis of progressive multifocal leucoencephalopathy (PML) can be confirmed by histological or virological examination of brain material. Whilst a less invasive method is provided by the detection of JC DNA in cerebrospinal fluid (CSF), very few studies have been done to assess the value of JC virus (JCV) serology in PML diagnosis.

OBJECTIVES

To study the JCV antibody response in the serum and CSF of PML patients.

STUDY DESIGN

A retrospective study was done using haemagglutination inhibition (HI), M-antibody capture radioimmunoassay (MACRIA) and JC-specific oligoclonal IgG banding on one or more sera and/or CSFs from 28 confirmed PML patients. Seventy-one serum and CSF samples were tested from patients with memory loss or dementia as a control group.

RESULTS

Twenty-seven PML patients (96%) had detectable JCV HI antibody in the serum, with titres ranging from 1 : 10 to > 1 : 20480, compared to 48 (68%) of the controls (P = <0.005). JCV IgM antibody was detected in the serum of 12/22 (55%) PML patients. JCV HI antibody was detected in the CSF in 12 of 18 (67%) PML patients, antibody index measurements being used to control for a possible breakdown of the blood-brain barrier. Intrathecal JCV antibody was not found in any control patient. Locally produced JCV-specific IgG bands were detected in the CSF of 7 PML patients tested, confirming the intrathecal origin and specificity of the HI antibody.

CONCLUSIONS

The presence of intrathecal JCV antibody indicates active central nervous system infection with JC virus, and provides a useful diagnostic test for PML, with a sensitivity of 67% and a specificity of 100%. The absence of serum JCV antibody nearly always excludes a diagnosis of PML, but the titre of antibody, IgG or IgM, correlates with the underlying condition rather than the development of neurological symptoms.

Detection of polyomaviral DNA sequences in normal and adenomatous human pituitary tissues using the polymerase chain reaction

BACKGROUND

Tumor viruses are known to have a role in the pathogenesis of many types of benign and malignant human tumors. The possible roles of these viruses in the development of human pituitary tumors have not been investigated.

METHODS

The polymerase chain reaction was used to screen human pituitary tumors for human papillomaviral (HPV) and Polyomaviral DNA sequences. Sets of consensus primers, which are capable of amplifying HPV Types 16, 18, and 33 and polyomavirus BK, JC, and SV40, were used in these experiments.

RESULTS

Amplification products were not detected using HPV consensus primers in 30 tumors. Twenty-six of 30 tumors demonstrated an amplification product with polyomaviral primers that hybridized to SV40 and BK internal probes and was confirmed to be SV40 in one tumor by direct sequencing. Ten normal postmortem pituitary samples then were examined similarly with Polyomaviral consensus primers; 8 of 10 normal samples demonstrated a similar amplification product that also hybridized with SV40 and BK internal probes by Southern blotting. Polyomaviral DNA sequences in normal and tumor samples were not present at levels detectable by genomic Southern blotting. Expressed viral protein (large T antigen) was not demonstrated in positive samples by Western blot analysis.

CONCLUSIONS

These findings, that polyomaviral DNA sequences are detectable at low levels in certain normal tissues, are in agreement with those of other groups and, to the authors' knowledge, serve as the first report of polyomaviral latency in human pituitary tissue. A role for polyomaviruses in pituitary tumorigenesis could not be established in this analysis.

Parent-to-child transmission is relatively common in the spread of the human polyomavirus JC virus

JC polyomavirus (JCV), the causative agent of progressive multifocal leukoencephalopathy, is ubiquitous in the human population, infecting children asymptomatically and then persisting in renal tissue. In most adults, renal JCV replicates and the progeny are excreted in urine. We used this urinary JCV to elucidate the routes of JCV transmission. A 610-bp JCV DNA region (IG region) encompassing the 3'-terminal sequences of both T-antigen and VP1 (major capsid protein) genes was amplified by means of PCR from urine specimens collected from all members of seven families. JCV strains were then unequivocally identified by the nucleotide sequences of the amplified IG regions. We could identify 18 distinctive JCV strains from 27 individuals. Different JCV strains were detected from all unrelated persons. However, the same viral strain was detected from one (four families), two (one family), or three offspring (one family) as well as from the fathers (three families) or from the mothers (three families). In total, the JCV strains detected in half of the JCV-positive children were identified in their parents. Since most humans are infected during childhood, these findings indicated that JCV is transmitted frequently from parents to children. We roughly estimated that 50% of JCV transmission occurs by this route and that the other 50% occurs outside the family.

Persistence of the SV40 early region without expression in permissive simian cells

SV40 containing recombinant vectors were introduced into permissive simian, non-permissive rodent and semi-permissive human cell lines, and assayed for transformation. All mouse and human cell clones expressed T-antigen (T-Ag) and were morphologically transformed when they contained only the wt T-Ag gene (E-SV40) or the entire wt viral genome with an interrupted late region. However, of 63 simian clones with these recombinant vectors, none became morphologically transformed and T-Ag containing cells were rare or absent. Nearly all simian cell lines made either no detectable early SV40 RNA or only small amounts of viral RNA but contained viral DNA restriction fragments similar to those in the original recombinant vectors. Functional T-Ag genes were recoverable from several cell clones and used to regenerate infectious virus. Hence, T-Ag gene expression had been suppressed. We found two conditions where T-Ag expression was activated. In a BSC-1 cell line containing E-SV40 DNA, subsequent introduction of a vector with a functional viral late coding region (L-SV40) resulted in the appearance of T-Ag and transformation. These findings suggest that L-SV40 sequences activate or enhance T-Ag expression and that this activation requires a functional Vpl gene. We found also, that vectors with E-SV40 DNA from the bipartite variant EL-SV40 consistently transformed simian CV-1 cells. Transformation was shown to be effected by the multiple alterations present in the regulatory region of this variant.

Brain and kidney of progressive multifocal leukoencephalopathy patients contain identical rearrangements of the JC virus promoter/enhancer

The kidneys of six progressive multifocal leukoencephalopathy (PML) patients were examined by PCR amplification for the presence of JC virus. Amplification of three different areas of the viral genome from multiple samples of each kidney revealed three that were positive for the virus. The use of a PCR-based typing assay on all tissue samples, and cloned sequences from the viral coding region from each positive kidney showed that the same viral genome was present in the kidney as in the brain of the patient. Regulatory region clones all had the archetypal promoter/enhancer structure. However, when PCR fragments from the regulatory region were digested with a restriction enzyme which cuts in region D, the region most often deleted in PML-type promoters, a low level of undigested DNA remained. This DNA refractory to digestion had a rearranged sequence identical to that of the unique rearranged promoter in the brain of each patient.

Transmission of the human polyomavirus JC virus occurs both within the family and outside the family

JC polyomavirus (JCV) is a ubiquitous symbiote in the human population, infecting children asymptomatically and then persisting in renal tissue. We reevaluated the urinary excretion of JCV in subjects in various age groups using PCR. The detection rate for urinary JCV DNA was 9 to 17% until the age of 20 years; this rate increased dramatically to about 46% at the ages of 20 to 29 years and then increased gradually with age. Therefore, it appears that in most people excretion of JCV begins at the age of 20 to 29 years, which is earlier than suggested previously. Next, we studied the way in which JCV is spread in the human population. We selected eight Japanese families in which both parents and children excreted JCV in their urine. Their JCV subtypes were determined by PCR amplification of a JCV DNA fragment; this was followed by restriction enzyme analysis. JCV species in all JCV-positive family members were classified into either of the two subtypes, subtypes CY and MY, which are prevalent in the Japanese population. The following features of JCV subtype distribution were seen in the families: (i) both subtypes were detected in children of five of the eight families, and (ii) of 21 children who excreted JCV, 14 children excreted the same subtypes excreted by their mothers or fathers, while the remainder (7 children) excreted subtypes different from those excreted by their parents. These features suggest that JCV is transmitted both within the family and outside the family. The data also indicate that vertical transmission is not common in the spread of JCV.

Multiple loci on human chromosome 11 control tumorigenicity of BK virus transformed cells

BK virus (BKV) is a human papovavirus that readily transforms rodent cells, but not human cells, to a neoplastic phenotype, suggesting that tumor-suppressor functions expressed in human cells control BKV oncogenicity. Transfer of a normal human chromosome 11 to BKV-transformed mouse cells suppresses the malignant phenotype. In this report we map the regions of chromosome 11 involved in tumor suppression. Transfer of chromosome 11 to the BKV-transformed hamster cell line HKBK produces monochromosomic hybrids retaining only portions of the transferred human chromosome. We have compared the tumorigenicity of the hybrids with the molecular mapping of chromosome 11 retained regions. This analysis indicated that 3 regions of human chromosome 11, 11p15.5, 11p13 and 11q13, cooperate in tumor suppression. However, 11q13 seems the most important, since all the HKBK/H11-induced tumors analysed had lost this region, whereas 11p15.5 and 11p13 were sometimes retained. The chromosomal regions identified in this study are deleted in several types of human tumors, suggesting that the BKV transformation system specifically detects tumor-suppressor genes on chromosome 11 that are involved in human oncogenesis. This model may be of use in isolating and cloning such genes. The results of this report raise the possibility that BKV may have a synergistic tumorigenic effect in human cells where tumor-suppressor genes controlling its oncogenic potential are inactivated.

A steroid hormone response unit in the late leader of the noncoding control region of the human polyomavirus BK confers enhanced host cell permissivity

The effect of steroid hormones on multiplication of the human polyomavirus BK (BKV) was studied. Physiological concentrations of the synthetic glucocorticoid dexamethasone, progesterone R5020, or estrogen 17 beta-estradiol enhanced the permissivity of the host cell for BKV, resulting in an up to 11-fold (dexamethasone), 5-fold (progesterone), or 3-fold (17 beta-estradiol) higher virus yield. The increase in virus yield in dexamethasone-stimulated cells correlated with enhanced steady-state levels of viral transcripts. The late leader sequence of the BKV control region contains a hormone response unit composed of a nonconsensus glucocorticoid and/or progesterone response element (GRE/PRE) and a fully consensus estrogen response element (ERE). DNA-protein binding studies showed that the glucocorticoid receptor and the progesterone receptor bound to this BKV GRE/PRE-like sequence, while the estrogen receptor could bind to the BKV ERE motif. By transient transfection assays, we were able to show that these sequences can mediate steroid hormone-induced gene expression. However, no cooperative transactivation effect between the BKV GRE/PRE-like motif and BKV ERE motif was observed. This BKV hormone response unit may play an important role in vivo by enhancing a productive BKV infection, and perhaps also by reactivating a latent infection, during physiological or pathological conditions accompanied by increased steroid hormone levels.

Effect of immunosuppression on the urinary excretion of BK and JC polyomaviruses in renal allograft recipients

Sixty-five renal allograft recipients on immunosuppressive therapy were examined for BK and JC viruria using Southern blot hybridization. The incidence and degree of BK and JC viruria were compared between this population (group RTR) and, an age- and sex-matched population of non-immunosuppressed individuals (group CTR). In the results, the incidence of BK viruria was significantly increased in the RTR group compared with the CTR group, while that of JC viruria was similar in the 2 groups. The proportion with a high level of JC viruria, however, was greater in the RTR group compared with the CTR group. Additionally, it was also demonstrated that the incidence of both BK and JC viruria was not affected by the characteristics of renal transplant recipients, such as differences in the donor source (living-related vs cadaveric), type of immunosuppressive agents used, or the time post-transplantation.

Detection by PCR of human polyomaviruses BK and JC in immunocompromised individuals and partial sequencing of control regions

Immunocompromised individuals were tested for the presence of the human polyomaviruses JC (JCV) and BK (BKV) by the polymerase chain reaction (PCR). The use of appropriate primers in a nested PCR allowed the detection of both viruses simultaneously. Viruses were differentiated by restriction fragment length analysis of amplified DNA fragments. Both BKV and JCV DNA were detected in the urine of an AIDS patient with progressive multifocal leukencephalopathy. In autopsy materials from this patient, JCV- but not BKV-DNA was found in brain and kidney tissue, whereas lung tissue was negative for both virus DNAs. To evaluate the methodology further, hybridization-positive urines from three recipients of bone marrow transplants and a positive urine of an acute myeloid leukemia patient were analyzed by this PCR method. One case was positive both for BKV and JCV, two cases were positive only for BKV, and one was negative for both. Parts of the control regions of JCV and BKV were sequenced directly from PCR-derived fragments. The JCV sequence from urine of the AIDS patient compared to sequences from a bone marrow transplant recipient and to archetypical reference strains showed two nucleotide (nt) exchanges out of 250 nt. The BKV sequences from the AML and the AIDS patients showed five nt exchanges out of 265 nt in the control region and were identified as BKV WW or WWT3 strains. In the agnogene region five exchanges were detected, two of them resulting in non-conservative amino acid exchanges. The possibility of testing clinical specimens of different origins by this PCR method is important for elucidating often unclear clinical courses in immunocompromised patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Progressive multifocal leukoencephalopathy in AIDS: a clinicopathologic study and review of the literature

We reviewed the clinical, radiographic, and pathologic features of 15 patients with the acquired immune deficiency syndrome (AIDS) and progressive multifocal leukoencephalopathy (PML). Brain tissue from 10 autopsy and 6 biopsy specimens was studied using: in situ hybridization (ISH) for JC virus (JCV), immunohistochemistry for human immunodeficiency virus (HIV) p24 antigen, and electron microscopy. Thirteen patients presented with focal neurologic deficits, while 2 presented with a rapid decline in mental status. PML was commonly the initial opportunistic infection of AIDS and produced hemiparesis, dementia, dysarthria, cerebellar abnormalities, and seizures. Magnetic resonance imaging was more sensitive than computed tomography in detecting lesions, and often showed multifocal areas of PML. CD4+ T-cell counts were uniformly low (mean 84/mm3), except in 1 patient who improved on 3'-azido-3'-deoxythymidine (AZT). PML involved the cerebral hemispheres, brain stem, cerebellum, and cervical spinal cord. The distribution of brain involvement was consistent with hematogenous dissemination of the virus. In 2 brain specimens, multiple HIV-type giant cells were present within the regions involved by PML. When co-infection by HIV and papovavirus was present, PML dominated the pathological picture. ISH for JCV showed virus in the nuclei of oligodendrocytes and astrocytes. Occasionally there was staining for JCV in the cytoplasm of glial cells and in the neuropil, the latter possibly a correlate of papovavirus spread between myelin sheaths, as seen by electron microscopy. ISH demonstrated more extensive foci of PML than did routine light microscopy.

Detection of reactivation and size variation in the regulatory region of JC virus in brain tissue

AIMS

To develop a sensitive and specific polymerase chain reaction (PCR) based system for detecting genomic variation in JC virus. To apply this system to formalin fixed, paraffin wax embedded brain tissue from patients with and without progressive multifocal leucoencephalopathy (PML).

METHODS

A pair of primers (JC1 and JC2) were designed to be complementary to the early and late regions of JC and BK polyomaviruses, respectively. A third primer (JC3), internal to JC1 and JC2, was designed to be specific for JC virus. The specificity of JC3 was investigated by amplifying plasmids with BK or JC virus genomes. Sensitivity was estimated by titration of a plasmid containing JC virus genome. Seven brains from patients with PML (PMLB) and 30 from patients without PML (non-PMLB) were amplified using JC1 and JC2, followed by JC1 and JC3. Amplification of the beta globin gene was used as an amplification control.

RESULTS

Amplification with JC1 and JC2 was common for JC and BK viruses, but with JC1 and JC3 it was specific for JC virus. The sensitivity of the system was 25 copies of JC plasmid per 10 microliters of digested tissue. Five out of seven PMLB and 28 of the 30 non-PMLB amplified for beta globin, but only the PMLB gave a signal with polyoma primers. Hypervariation of the length of the regulatory region of the JC isolates in the PML tissues was consistent with the presence of multiple strains of JC.

CONCLUSIONS

Variation in the regulatory region of JC virus can be specifically and sensitively detected from routinely processed, paraffin wax embedded brain tissue. Variation in the regulatory region is common in PML derived JC strains, but JC virus was not detectable in non-PMLB tissue.

Origin of JC polyomavirus variants associated with progressive multifocal leukoencephalopathy

JC polyomavirus (JCV) DNAs from the urine of nonimmunocompromised individuals (designated archetypal isolates) regularly contain a regulatory sequence that may have generated various regulatory sequences of JCV isolates derived from the brain of patients with progressive multifocal leukoencephalopathy (PML). In this report, we constructed a phylogenetic tree for 14 isolates (7 archetypes and 7 PML types) from DNA sequence data on the VP1 (major capsid protein) gene. According to the phylogenetic tree, the 14 isolates diverged into types A and B, each of which contained archetypal and PML-type isolates. Each type further diverged into several groups containing archetypal and PML-type isolates. We conclude that PML-type isolates are polyphyletic in their origin and do not constitute a unique lineage. This conclusion suggests that PML-type JCV isolates are generated from archetypal strains during persistence in the hosts. Furthermore, the present phylogenetic analysis indicates that an ancestral JCV carried the archetypal regulatory sequence and that this structure has been conserved in the course of JCV evolution.

Adult mouse kidneys become permissive to acute polyomavirus infection and reactivate persistent infections in response to cellular damage and regeneration

Kidneys of newborn (but not adult) mice are normally high permissive for polyomavirus (Py) infection and readily establish persistent infections. We have proposed that ongoing cellular differentiation, which occurs in newborn mice, may be necessary for a high level of in vivo Py replication (R. Rochford, J. P. Moreno, M. L. Peake, and L. P. Villarreal, J. Virol. 66:3287-3297, 1992). This cellular differentiation requirement may also be necessary for the reactivation of a persistent Py kidney infection and could provide an alternative to the accepted view that reactivation results from immunosuppression. To examine this proposal, the ability of adult BALB/c mouse kidneys to support primary acute Py infection or to reactivate previously established persistent Py infections after kidney-specific damage was investigated. Kidney damage was induced by both chemical (glycerol, cisplatin, or methotrexate) and mechanical (through renal artery clamping to produce unilateral renal ischemia) treatments. We also examined the effects of epidermal growth factor (EGF), which enhances the rate of kidney regeneration, on Py replication. Using histopathologic techniques, in situ hybridization for Py DNA, and immunofluorescence for Py VP1 production, we established that both chemical damage and damage through renal artery clamping of adult kidneys promoted high levels of primary Py replication in these normally nonpermissive cells. This damage also promoted the efficient reactivation of Py replication from persistently infected kidneys, in the absence of immunosuppression. EGF treatment significantly increased acute Py replication and also reactivation in damaged kidneys. These results support the view that ongoing cellular division and differentiation may be needed both for high levels of acute Py replication and for reactivation of persistent infections in vivo.

BK virus antigenic variants: sequence analysis within the capsid VP1 epitope

DNA sequences for the VP1 gene which codes for the major capsid protein of BK virus (BKV) and may be responsible for antigenic variability were determined for seven BKV isolates. The observed sequence differences and those previously reported correlate with the typing of isolates into four groups by haemagglutination inhibition. Amino acid coding alterations were found to be clustered within residues 61 to 83. Each antigenic group was found to have a characteristic amino acid sequence between residues 61 and 83. Several clones originating from a single isolate, although differing slightly in restriction enzyme digestion patterns, were found to be identical in this region. The VP1 sequences of three of the four groups were analysed by hydropathy plots and two hydrophilic areas of high antigenicity were identified. One of these corresponds to residues 61 to 83 and it is postulated that this region is the epitope responsible for serotypic differences between BK isolates.

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.

Evidence of human polyomavirus BK and JC infection in normal brain tissue

Infection with the polyomaviruses JC and BK is ubiquitous in the human population and JCV is the only virus associated with the central nervous system disease progressive multifocal leukoencephalopathy. In the attempt to analyze the pathogenesis of polyomavirus infections we asked whether human polyomaviruses invade the brain during persistence. Brain autopsy material from 67 individuals with disorders other than PML was examined for the presence of polyomavirus DNA. Southern blot analysis demonstrated JCV-specific full-length virus genomes in healthy brain tissue in about 20% of the patients. Type-specific analysis with polymerase chain reaction and sequencing confirmed these data. Additionally, the presence of BKV DNA sequences covering an early gene fragment and the control region with flanking early and late protein coding sequences was detected. Cloning of the complete BKV genome from two cases supported the assumption that not only full-length JCV DNA was present in those tissue specimens but also BKV genomes. The data obtained demonstrate that dual infection of the brain with the polyomaviruses JCV and BKV is a common event and give strong evidence that both viruses frequently establish a latent CNS infection.

JC virus DNA is present in many human brain samples from patients without progressive multifocal leukoencephalopathy

Sections of normal and diseased brain and kidney tissues were screened for the presence of JC virus (JCV) DNA by using the polymerase chain reaction. As expected, all samples obtained from patients with progressive multifocal leukoencephalopathy (PML) tested positive when multiple JCV-specific primer and probe combinations were used. Unexpectedly, more than 50% of non-PML-affected brains were also found to harbor low levels of JCV DNA. To confirm that the positive signals seen in the tissue sections were not the result of contamination, amplified DNA was cloned and sequenced and in some cases was shown to represent strains of JCV not identified previously. Two predominant regulatory region configurations of JCV have been detected in the human host: archetype JCV, which is excreted in the urine of normal and immunocompromised individuals, and "PML-type" JCV found in diseased brains. This latter group of variants appears to derive from archetype JCV by the deletion and duplication of sequences within the promoter-enhancer region. In the present study, the archetype strain of JCV was identified only in normal kidney samples; JCV DNA found in non-PML-affected brain specimens and in kidney tissue from patients with PML resembled that of strains isolated from PML-affected brain tissue. Our findings indicate that JCV reaches the brain more frequently than previously thought and may persist at this site without causing demyelinating disease. A subsequent episode of prolonged immunodeficiency or a direct interaction with an immunocompromising agent (e.g., human immunodeficiency virus type 1) might activate the latent JCV infection and lead to the development of PML.

An M-antibody capture radioimmunoassay (MACRIA) for detection of JC virus-specific IgM

A solid-phase M-antibody capture radioimmunoassay (MACRIA) for detecting JC-specific IgM is described. The assay is based on a JC-specific monoclonal antibody (17.7.6) and Nonidet P40-treated, glycine-extracted antigen. MACRIA is more sensitive for JC IgM detection than haemagglutination inhibition (HI) following serum fractionation on a sucrose density gradient, and can be applied to large numbers of sera. The specificity of the assay was confirmed by examining sera from several acute virus infections and also those containing rheumatoid factor. Sera collected from renal transplant recipients with known active JC virus infection were found to contain more than 5 units of JC IgM. In this group of patients JC IgM represents either primary or reactivated JC infection. JC IgM was detected by MACRIA in 15 of 100 unselected blood donors, indicating that JC IgM is frequently produced in healthy seropositive individuals. Thirteen of the 15 sera positive from blood donors contained only low levels of JC IgM (< 5 units), but the specificity of all these results was confirmed in a blocking assay. It is suggested that these low levels of JC IgM may occur in up to 28% of seropositive individuals and result from active JC antigenic stimulation in healthy immunocompetent adults.

Antibody response to human papovavirus JC (JCV) and simian virus 40 (SV40) T antigens in SV40 T antigen-transgenic mice

Human papovavirus JC (JCV) and simian virus 40 (SV40) genomes share approximately 69% homology; and there is antigenic cross-reactivity between JCV and SV40 tumor or T antigens. In order to determine whether a selective immune response to JCV T antigen could be demonstrated, transgenic mice (SV11+) that express SV40 T antigen in the choroid plexus and are partially tolerant to antigenic determinants on SV40 T antigen were immunized with SV40 or JCV T antigens and their antibody responses were analyzed. The results show that SV11+ mice responded as well as their nontransgenic litter mates to JCV T antigen. Monoclonal antibodies were derived from hybridomas generated from immunized mice which reacted specifically with epitopes in the amino and carboxy terminal halves on JCV T antigen. These studies show that transgenic mice expressing SV40 T antigen are capable of responding to determinants not shared between JCV and SV40 T antigen.

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.

Transformed rat pancreatic islet-cell lines established by BK virus infectionin vitro

Single-cell suspensions of primary rat pancreatic islet cells were infected with BK virus (BKV) prototype (Gardner) and the naturally occurring BKV strain (TU), isolated from human urine. These viral strains have different sequences in their non-coding control regions which contain promoter-enhancer elements and origin of DNA replication. Uninfected cell cultures disintegrated within 3 weeks, while a varying number of virus-infected cultures were immortalized and a majority exhibited focal areas of 2-dimensional growth. A significantly higher proportion of the BKV (TU)- than of the BKV (Gardner)-infected cultures were immortalized. Large tumor (T) antigen expression was evident in virus-infected cultures from day 4 post infection (p.i.), while insulin secretion decreased steadily during the first weeks of culture. Two cell lines were established from BKV (TU)-infected cultures. Line 5A4 was contact-inhibited, growing as a dense monolayer, while 6A3 demonstrated foci of 2-dimensional growth. Both cell lines have retained their morphology and T-antigen expression for approximately 130 passages. At high passages a low level of intracellular insulin, but no secretion into media, was detected. Based on standard biological tests (reduced serum requirements, growth at low cell density, anchorage-independent growth and tumor induction in nude mice) both cell lines have a fully transformed phenotype, but 6A3 appears to be more malignantly transformed. Since both cell lines were established simultaneously from the same primary cells with the same virus batch, they provide an opportunity to study the transforming mechanisms of BKV in a relative context.