JC virus associated meningoencephalitis in an immunocompetent girl

JC virus is most commonly acquired during childhood, and no clinical illness has been associated with primary infection, which is assumed to be asymptomatic. The only disease associated with JC virus to date is progressive multifocal leucoencephalopathy (PML), which is usually caused by viral reactivation in immunocompromised adults. A chronic meningoencephalitis associated with an active JC virus infection in an immunocompetent 13 year old girl is described.

Altered DNA binding and replication activities of JC virus T-antigen mutants

Ten mutations were introduced into the JC virus (JCV) T antigen within a region corresponding to the SV40 T-antigen DNA binding domain (SV40 amino acids 131 to 220); nine of these increased homology between the two proteins in sequences critical for SV40 T antigen DNA binding. All mutant JCV T antigens bound to JCV and SV40 origins of DNA replication. Binding efficiency relative to the of wild-type JCV T antigen ranged from 83 to 301% for the JCV binding sites and from 44 to 240% for the SV40 binding sites. Nine mutant proteins promoted viral DNA replication in primary human fetal glial (PHFG) and CV-1 cells. In PHFG cells, promotion of DNA replication ranged from 26 to 220% relative to that of wild-type T antigen; in CV-1 cells it ranged from 14 to 522%. Coding sequences for five mutant proteins were transferred into the hybrid virus M1 (SV40) [M1(SV40) contains coding sequences from JCV and regulatory sequences from SV40]. Wild-type T antigen promoted replication weakly from the SV40 origin in these hybrid viruses in CV-1 cells (2% that from the JCV origin); replication driven by the mutant proteins ranged from 110 to 412% of that induced by the wild-type protein. Efficient specific DNA binding by a mutant T antigen was not a reliable indicator of that mutant protein's ability to promote DNA replication.

Preparation of monoclonal antibodies to JC virus and their use in the diagnosis of progressive multifocal leucoencephalopathy

Seven monoclonal antibodies (MAbs) to polyomavirus JC were produced, and one was selected for use in immunofluorescence (IF) tests on brain material from patients with suspected progressive multifocal leucoencephalopathy (PML). The selected MAb (5.12.2) reacted by IF with JC-infected primary human foetal glial (PHFG) cell cultures (titre 1/200,000) but not with BK-infected human embryo lung (HEL) fibroblasts (titre less than 1/20). Its haemagglutination-inhibition (HI) titre was high (greater than 1/5 x 10(6)) against JC virus but low (less than 1/5) against BK virus. A diagnosis of PML was confirmed on brain biopsy or at postmortem in four patients, two of whom were also infected with human immunodeficiency virus (HIV). In one of the patients, specific detection of JC virus antigen had not been possible using our routine high titred JC and BK human sera due to interference by JC antibody present in the cerebrospinal fluid (CSF). Viral antigen was, however, detected with the MAb 5.12.2.

Identification of critical elements within the JC virus DNA replication origin

The T antigen of JC virus (JCV) does not interact productively with the simian virus 40 (SV40) origin of replication. In contrast, the SV40 T antigen does drive replication from the JCV origin as well as from its own. The basis for this restricted interaction was investigated by analyzing the structure of the JCV replication origin. The replication activities of JCV-SV40 hybrid origin plasmids were tested in cells constitutively producing either the JCV or SV40 T antigen. Results indicated that a region of the JCV origin critical for interaction with the JCV T antigen was positioned to the late side of the central palindrome of the putative core origin. A mutational analysis of this region indicated that the sequence of the A + T-rich tract was primarily responsible for determining the efficiency with which JCV can initiate replication from its origin. The tandemly repeated pentameric sequence AGGGA located proximal to the A + T-rich tract in the JCV enhancer element was found to stimulate JCV, but not SV40, T antigen-mediated replication. The effect on replication of other elements within the JCV enhancer was also dependent on the T antigen employed for initiation. A plasmid containing the replication origin of prototype BK virus was unable to replicate in cells containing JCV T antigen, again indicating the inflexibility of the JCV T antigen in interacting with heterologous origins.

Regulation of the human neurotropic virus promoter by JCV-T antigen and HIV-1 tat protein

We compared the ability of HIV-1 tat protein and JCV T-antigen in inducing transcription from the JCV late promoter, JCVL. A JCVL promoter-chloramphenicol acetyltransferase plasmid (pJCL-CAT) was transfected into human glial cells alone or together with plasmids producing T-antigen and tat protein. CAT enzyme activity obtained from the transfected cells indicated that both JCV T-antigen and HIV-1 tat proteins stimulated JCV late gene expression. However, the level of induction mediated by tat protein was significantly higher than that obtained with T-antigen. Moreover, in contrast to JCV T-antigen, tat stimulated JCVL-promoter activity over a narrow range of ptat expressor plasmid concentration. Co-transfection of both T-antigen and tat plasmids at optimal concentrations resulted in greater than additive CAT activity from the JCVL promoter. This synergism suggests that the two activator proteins utilize alternative mechanisms to exert their effects. Using deletion mutations from the 5' end of the JCVL promoter, we demonstrated that different regions within the JCV enhancer/promoter are important for T-antigen and tat induction, implying that these activators function through distinct targets to increase JCVL promoter activity.

Severe encephalitis resulting from coinfections with HIV and JC virus

We observed 3 cases of progressive multifocal leukoencephalopathy (PML) among frozen CNS samples obtained at autopsy from 102 adult AIDS patients. In 2 patients, PML was associated with severe HIV encephalitis. In those 2 cases, the areas of extensive JC-induced demyelination were massively infiltrated by HIV infected macrophages/microglial cells with evidence for localized increase of HIV encephalitis in PML lesions. Using immunohistochemistry and in situ hybridization, we demonstrated that each virus infects, in a latent or productive fashion, different CNS cell populations. Therefore, the extension of HIV encephalitis could not be related to an intracellular transactivation of 1 virus by the other. However, the results are consistent with dissemination of viral infection by the recruitment of HIV-infected macrophages to damaged areas of the brain. This phenomenon might be generalized to other pathogens that are frequently associated with HIV CNS infection. Early detection and treatment of opportunistic CNS lesions could be important to prevent extension of HIV encephalitis.

Immunolabeling of JC virus large T antigen in neonatal hamster brain before tumor formation

Using immunolabeling methods, the JC virus (JCV) early or regulatory protein, large T antigen, was demonstrated in frozen sections of neonatal hamster brains before tumor formation. Three days after intracerebral inoculation of 2500 hemagglutinating units of JCV, T antigen was expressed predominantly in nuclei of cells in the external granular layer and newly forming internal granular layer of the cerebellum and also in cell nuclei located in the hippocampus, periventricular areas, and the olfactory bulb. At 7 days postinoculation (p.i.), most cerebellar T antigen-containing cells had migrated to the internal granular layer, but by 15 days p.i., cells that expressed T antigen was greatly reduced in number or absent. However, by 30 days p.i., the internal granular layer of the cerebellum again contained T antigen-positive cells. In contrast to the scattered cells seen at 3 or 7 days p.i., these cells appeared in dense clusters thought to represent pretumor foci. Since JCV capsid proteins were not detected at any time, JCV may establish a latent or abortive infection in cells during their mitotic phase and these cells initially express T-antigen during migration or become immunoreactive later before tumor formation.

[Simultaneous in situ detection of JC virus antigens and RNA in progressive multifocal leukoencephalopathy (PML) by immunocytochemistry and in situ hybridization]

We detected simultaneously JC virus (JCV) antigen and RNA in the frozen brain tissue from a patient with PML using immunocytochemistry and in situ hybridization. Histologically, the majority of JCV antigen positive cells were mainly located at the margin of demyelinated lesions. By simultaneous in situ detection of JCV antigen and RNA, the percentage of both JCV antigen and RNA positive cells in total number cells were 20 in the periplaque region and 2.3 in the central region of plaque respectively. On the contrary, only JCV RNA positive cells were detected 3.6% in the periplaque region and 4.6% in the central region of plaque, while there was not found any positive cells in apparently normal white matter. Moreover, JCV antigen in both antigen and RNA positive cells found in the periplaques was stained homogeneous and filled the whole swollen nucleus, whereas most of both antigen and RNA positive cells appeared in the center of plaques showed small amounts of antigen in the nucleus. From the results, it seems likely that most of the cells displaying only RNA detected in the periplaque were oligodendrocytes in the early stages of productive infection prior to viral protein synthesis. However, a small number of cells displaying only RNA in the center of plaques were likely to be oligodendrocytes and seemed to be in the nonproductive stages of a JCV infection, limited expression of viral protein, influenced by the host immune response including the infiltration of macrophages and humoral immunity.

Cell type-specific expression of JC virus T antigen in primary and established cell lines from transgenic mice

The highly restricted host range of JC virus (JCV) has made it difficult to study the biology of this common human papovavirus. To increase our understanding of the tissue specificity of this virus, we have examined the expression of the T antigen (T-Ag) in primary and established cell lines from various tissues of transgenic mice containing the JCV early region. In contrast to earlier results from a simian virus 40-containing transgenic mouse, there was no T-Ag expression in mesenchymal fibroblasts derived from two lines of JCV-transgenic mice. Instead, we isolated T-Ag-positive (T-Ag+) cells that had characteristics consistent with a neural crest origin. Furthermore, primary brain cultures contained many T-Ag+ astrocytes, but no expression was detected in macrophages, epithelial cells, neuronal cells nor, surprisingly, in oligodendrocytes. Continued passage of these cultures resulted in vigorously growing glial fibrillary acidic protein-positive, T-Ag+ astrocytes. Thus, the strict tissue specificity of JCV expression was maintained, despite the fact that the viral genome pre-existed in every tissue of these transgenic mice and these constraints on expression were preserved even when cells were explanted in vitro.

Progressive multifocal leukoencephalopathy-remission with cytarabine

A 51-year-old woman who was in complete remission from non-Hodgkin's lymphoma, developed a rapidly progressive dementia. Progressive multifocal leukoencephalopathy (PML) was diagnosed on the basis of a rising antibody titre to JC polyomavirus in cerebro-spinal fluid and serum and the presence of diffuse white matter changes on magnetic resonance imaging. She was treated initially with intravenous cytarabine and showed minimal improvement. Rapid improvement occurred when intrathecal cytarabine was added and the patient is in complete remission from both lymphoma and PML 20 months later.

The cellular 107K protein that binds to adenovirus E1A also associates with the large T antigens of SV40 and JC virus

The association between the retinoblastoma protein (p105-RB) and either the large T antigen of SV40 or the E1A proteins of adenovirus is thought to be an important step in transformation by these viral oncogenes. E1A and large T antigen share a small region of amino acid homology that is necessary for high affinity binding with p105-RB. Mutations of this homology region were shown to reduce drastically the frequency of transformation mediated by the E1A or large T oncogenes. Previously, this small region in E1A was shown to be sufficient for interaction with a second cellular protein of 107,000 daltons (107K). Here we show that in human cells, the large T antigens of SV40 or JC virus also form complexes with 107K. Demonstration of complexes between 107K and the large T antigens of SV40 and JC virus suggests that these associations may represent another component of a common mechanism for transformation between adenoviruses and polyoma viruses.

Serological typing scheme for BK-like isolates of human polyomavirus

Human polyomavirus BK-like isolates were subjected to restriction endonuclease analysis with the enzymes EcoRI and Hind III. End-point dilution was used to obtain homogeneous virus pools for DNA analysis and to remove JC virus from a mixed stock. The results of Hind III digestion suggested that two subgroups could be distinguished. Several BK-like isolates were purified and rabbit antisera raised. The isolates were compared with each other and with BK and JC viruses by haemagglutination-inhibition (HI) and by neutralisation. JC virus was serologically distinct, but all the other isolates showed some cross-reactivity. Two subgroups were again evident: GS and PG were with prototype BK in subgroup 1, and MG and IV were in subgroup 2. Two isolates, AS and SB, reacted with isolates of both subgroups 1 and 2 but were distinct from one another: their genome was similar to subgroup 1 isolates. Typing by HI or by neutralisation may form a basis for grouping BK-like polyomavirus isolates.

Extinction of JC virus tumor-antigen expression in glial cell--fibroblast hybrids

JC virus (JCV) is a ubiquitous human papovavirus that shares sequence and structural homology with simian virus 40 (SV40). In contrast to SV40, expression of JCV is restricted to a small number of cell types, including human fetal glial cells, uroepithelial cells, amnion cells, and some endothelial cells. To study the control of JCV early region expression, we made heterokaryons and stable hybrids between JCV-transformed hamster glial cells and mouse fibroblasts. Binucleate heterokaryons exhibited extinction of large tumor antigen expression in the hamster nuclei as assayed by indirect immunofluorescence. This extinction was both time and dose dependent: extinction reached maximal levels at 24-36 hr after fusion and was dependent on the ratio of glial cell to fibroblast nuclei in multinucleated heterokaryons. Extinction also was observed in stable hybrids between the glial cells and mouse Ltk- cells. Southern blot analysis showed that the extinguished hybrids contained viral sequences. Reexpression of large tumor antigen was observed in several subclones, suggesting that extinction was correlated with the loss of murine fibroblast chromosomes from these hybrids. The cis-acting region that mediates extinction resides within the viral regulatory region, which contains two 98-base-pair repeats that have enhancer activity. These data demonstrate that cellular factors that negatively regulate viral gene expression contribute to the restricted cell-type specificity of this virus.

BK and JC virus infections in recipients of bone marrow transplants

Fifty-five recipients of bone marrow transplants were monitored prospectively for urinary excretion of BK (BKV) and JC (JCV) viruses and for infections with other viruses. For both BKV and JCV, viruria occurred exclusively in patients who were seropositive at transplantation, a finding indicating that shedding of virus was very likely the result of reactivation. BKV reactivation, which occurred in 26 (55%) of 47 BKV-seropositive patients, was far more common than JCV reactivation, which was detected in only two (7%) of 30 JCV-seropositive patients (P less than .0001). In most patients, BK viruria began two to eight weeks after transplantation and resolved spontaneously after a two- to three-week period. Posttransplantation, there was a temporal pattern in the onsets of infection with the different viruses; herpes simplex virus infections occurred first (mean, 7 d), followed by BKV infections (mean, 33 d) and then cytomegalovirus infections (mean, 51 d). BK viruria was associated with hemorrhagic cystitis.

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

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

A serological investigation of BK virus and JC virus infections in recipients of renal allografts

BK virus (BKV) and JC virus (JCV) infections were evaluated in a serological study of 496 renal transplant recipients and their donors. A seropositive donor increased the rate of primary and reactivation infections with BKV and of primary infections with JCV. BKV infection rates were not influenced by the source of the renal allograft (cadaver versus living related donor); however, primary JCV infections occurred more often in recipients of seropositive cadaveric kidneys. Reactivated JCV infections occurred less frequently in patients treated with antilymphocyte preparation. BKV and JCV infections in renal transplant recipients may be caused either by reactivation of the recipient's latent virus or by virus from the donor kidney. These infections are, however, not associated with adverse outcome (death, high serum creatinine level, or loss of renal function) in the recipient in the early post-transplant period.

A monoclonal antibody to SV40 large T-antigen labels a nuclear antigen in JC virus-transformed cells and in progressive multifocal leukoencephalopathy (PML) brain infected with JC virus

Thirty monoclonal antibodies to SV40 large T-antigen were tested for reactivity on the JC virus-transformed hamster glial cell line known as HJC-15. Two of them (PAb 416 and PAb 108) detected a nuclear antigen in both SV40-transformed CCL 75.1 cells and in HJC-15 cells, but not in control cells lacking T-antigen. These same antibodies also labeled a nuclear antigen in hamster tumor tissue derived from HJC-15 cells. In addition, the monoclonal antibody PAb 416 detected a nuclear antigen in progressive multifocal leukoencephalopathy (PML) tissue infected with JC virus, but not in normal brain tissue or tissue from other neurological diseases. Staining by PAb 416 was reduced by prior incubation with hamster anti-JCV tumor serum, suggesting that the polyclonal antiserum to JCV T-antigen may compete for an epitope at or near the PAb 416 binding site.

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

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

Characterization of cells transformed by the human polyomavirus JC virus

One unique feature of the prototype JC virus (JCV) (Mad 1) genome is the occurrence of a second TATA sequence within the early promoter region. A naturally occurring oncogenic variant of JCV (Mad 4) lacks this second TATA box. Several cell lines transformed by Mad 1, Mad 4 and simian virus 40 were characterized, in part to investigate whether the second TATA sequence is functional. S1 nuclease mapping of early JCV gene transcription products revealed a major set of start sites common to both Mad 1 and Mad 4 mRNAs. In addition, a second set of early transcripts was found exclusively in Mad 1 transformants, presumably positioned by the second TATA box. The presence of these unique mRNAs in the Mad 1-transformed cells did not appear to have any bearing on the other parameters investigated, including size and quantity of early viral proteins, integration patterns of viral DNA and growth properties of the cells.

The early region of human papovavirus JC induces dysmyelination in transgenic mice

Transgenic mice containing the early region of human papovavirus JC were produced. Some of these mice exhibited a shaking disorder similar to the previously described mutant mice jimpy or quaking. Neuropathological analysis indicated a dysmyelination in the central nervous system, but not the peripheral nervous system. A high level of JCV T-antigen mRNA was present in the brains of the mice exhibiting the myelin disorder. JC virus is associated in humans with a degenerative demyelinating disease: progressive multifocal leukoencephalopathy. The JCV-containing transgenic mice may therefore provide an animal model for studying this disease.

JC papovavirus large tumor (T)-antigen expression in brain tissue of acquired immune deficiency syndrome (AIDS) and non-AIDS patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a JC papovavirus infection of the central nervous system in immunocompromised patients. It is well established that demyelination in PML is caused by JC virus infection of oligodendroglia, but whether the nonstructural regulatory protein, large tumor (T) antigen, is detectable in infected human tissue was not known. Using a modification of the peroxidase-antiperoxidase technique, we found T antigen expressed in the nuclei of cells in virus-infected sites in five cases of PML studied, including two with acquired immune deficiency syndrome (AIDS). PML occurs in AIDS at a much higher frequency than in other immunosuppressive disorders, and PML in AIDS may represent a more severe form of JC virus infection of the central nervous system.

Immunoenzymatic labelling of JC papovavirus T antigen in brains of patients with progressive multifocal leukoencephalopathy

Formalin-fixed, paraffin-embedded autopsy sections of brains from two patients with progressive multifocal leukoencephalopathy (PML) were stained by peroxidase-antiperoxidase methods for human papovavirus T antigen, a nonstructural protein expressed in cells lytically infected or transformed by JC, BK, and SV40 viruses. Adjacent sections were stained for papovavirus common structural antigen, a component of JC, BK, and SV40 virions which is synthesized in productively infected but not transformed cells. Intense immunoperoxidase labelling specific for T antigen was detected in large numbers of oligodendrocytes at the edges of demyelinated areas and in occasional oligodendrocytes within otherwise normal brain. Occasional morphologically normal astrocytic cells exhibited similar specific staining, but only rate atypical astrocytic cells contained detectable amounts of T antigen. Examination of adjacent sections stained with antisera to common structural antigen revealed an identical pattern of immunoenzymatic labelling, indicating that most of the cells expressing T antigen were also expressing viral structural proteins. The present study demonstrates that T antigen can be identified by immunoperoxidase methods in routinely processed autopsy material from cases of PML, but that detectable amounts of antigen are found almost exclusively in cells undergoing lytic infection.