The effect of potent antiretroviral therapy and JC virus load in cerebrospinal fluid on clinical outcome of patients with AIDS-associated progressive multifocal leukoencephalopathy.
(33/512)
A multicenter analysis of 57 consecutive human immunodeficiency virus-positive patients with progressive multifocal leukoencephalopathy (PML) was performed, to identify correlates of longer survival. JC virus (JCV) DNA was quantified in the cerebrospinal fluid (CSF) by polymerase chain reaction. Two months after therapy, 4% of the patients without highly active antiretroviral therapy (HAART) and 26% with HAART showed neurologic improvement or stability (P=.03), and 8% and 57%, respectively, reached undetectable JCV DNA levels in the CSF (P=.04). One-year probability of survival was.04 without HAART and.46 with HAART. HAART and lack of neurologic progression 2 months after diagnosis were independently associated with longer survival. Among HAART-treated patients, a baseline JCV DNA <4.7 log, and reaching undetectable levels after therapy predicted longer survival. Survival of AIDS-related PML is improved by HAART when JCV replication is controlled. (+info)
Human cytomegalovirus immediate-early gene 2 expression leads to JCV replication in nonpermissive cells via transcriptional activation of JCV T antigen.
(34/512)
Human papovavirus JCV is the causative agent of the demyelinating brain disease progressive multifocal leukoencephalopathy (PML) that typically develops as a complication of impaired immunocompetence. JCV displays a strong tropism for glial cells which is correlated by glial-specific transcriptional regulation of viral gene expression. In a previous report HCMV was shown to overcome the restricted cell specificity of JCV by inducing DNA replication of a PML-derived JCV strain in human fibroblasts which are nonpermissive for the replication of JCV alone. Here we show that productive JCV replication is induced by HCMV in human glioblastoma cells. Both in fibroblasts and in glioblastoma cells, the HCMV immediate-early transactivator 2 (IE2) is sufficient to mediate JCV replication. Furthermore, IE2 induces DNA replication of several structurally different brain- or kidney-derived JCV variants. IE2-induced JCV DNA replication is accompanied by the induction of JCV T antigen expression due to stimulation of the JCV early promoter. Our results indicate that stimulation of JCV early gene expression by HCMV-IE2 is sufficient to overcome the restricted cell specificity of JCV. (+info)
Rapid quantification and differentiation of human polyomavirus DNA in undiluted urine from patients after bone marrow transplantation.
(35/512)
A combined PCR assay was developed for the detection and typing of human polyomavirus (huPoV) in clinical samples, consisting of (i) a qualitative seminested PCR assay (snPCR) to discriminate between huPoV BK and JC and (ii) a high-throughput, quantitative TaqMan PCR assay (TM-PCR) for the general detection of huPoV. The TM-PCR detects huPoV DNA in a linear range from 10(7) to 10(1) copies per assay. In reproducibility runs, the inter- and intra-assay variabilities were < or =60 and < or =50%, respectively. The snPCR assay uses a set of four primers for the same region of the BK and JC viral genomes. In the first round of amplification, two general primers were used; in the second round, one of these general primers and two additional, BK- or JC-specific primers were used simultaneously to produce amplicons of different sizes specific for BK virus (246 bp) and JC virus (199 bp), respectively. We tested different urine dilutions in order to determine the inhibitory effects of urine on PCR amplification. Furthermore, we compared the use of native urine with DNA purified by different preparation procedures. Our results show, that a 1:10 dilution of the urine led to complete reduction of the amplification inhibition found with 6% of undiluted urine samples. In a clinical study including 600 urine specimens, our assay turned out to be fast, cheap, and reliable in both qualitative and quantitative aspects. (+info)
Pituitary neoplasia induced by expression of human neurotropic polyomavirus, JCV, early genome in transgenic mice.
(36/512)
In recent years, there has been mounting evidence pointing to the association of polyomaviruses with a wide range of human cancers. The human neurotropic polyomavirus, JCV, infecting greater than 75% of the human population produces a regulatory protein named T-antigen which is expressed at the early phase of viral lytic infection and plays a critical role in completion of the viral life cycle. Furthermore, this protein has the ability to transform neural cells in vitro and its expression has been detected in several human neural-origin tumors. To further investigate the oncogenic potential of the JCV early protein in vivo, transgenic mice expressing JCV T-antigen under the control of its own promoter were generated. Nearly 50% of the animals developed large, solid masses within the base of the skull by 1 year of age. Evaluation of the location as well as histological and immunohistochemical data suggest that the tumors arise from the pituitary gland. As T-antigen is known to interact with several cell cycle regulators, the neoplasms were analysed for the presence of the tumor suppressor protein, p53. Immunoprecipitation/Western blot analysis demonstrated overexpression of wild-type, but not mutant p53 within tumor tissue. In addition, co-immunoprecipitation established an interaction between p53 and T-antigen and overexpression of p53 downstream target protein, p21/WAF1. This report describes the analysis of inheritable pituitary adenomas induced by expression of the human polyomavirus, JCV T-antigen in transgenic mice where T-antigen disrupts the p53 pathway by binding to and sequestering wild-type p53. This animal model may serve as a useful tool to further evaluate mechanisms of tumorigenesis by JCV T-antigen. (+info)
Expression of Bax, Bcl-2, and P53 in progressive multifocal leukoencephalopathy.
(37/512)
It has been shown in vitro that JC viral protein can form a complex with wild-type p53 protein, which is a key regulator of both cell proliferation and cell death. Cellular factors, Bax and Bcl-2, are two essential downstream elements involved in p53-dependent apoptosis. To determine whether association of JC virus with p53 protein affects the expression of Bax and Bcl-2 in viral-infected cells in progressive multifocal leukoencephalopathy (PML), we studied the expression of Bax, Bcl-2, and p53 in 14 cases from 13 PML patients by using paraffin immunohistochemistry. Seven of 13 patients were known to be HIV positive. Overexpression of p53 was found in viral-infected oligodendrocytes and some astrocytes in all 14 cases. Intense immunostaining of Bax was strongly expressed in viral-infected oligodendrocytes and astrocytes. Bax immunostaining was also found in macrophages in the demyelinating lesions. Bcl-2 was not detected in viral-infected glial cells. The expression pattern of Bax positive/Bcl-2 negative in viral-infected glial cells suggests that the oligodendrocyte may be undergoing apoptosis which may in turn contribute to the demyelinating process in PML. The coexpression of p53 and Bax in the infected glial cells suggests that p53 detected by immunohistochemistry may still maintain its wild-type function. (+info)
Population structure and history in East Asia.
(38/512)
Archaeological, anatomical, linguistic, and genetic data have suggested that there is an old and significant boundary between the populations of north and south China. We use three human genetic marker systems and one human-carried virus to examine the north/south distinction. We find no support for a major north/south division in these markers; rather, the marker patterns suggest simple isolation by distance. (+info)
JC virus genotypes in France: molecular epidemiology and potential significance for progressive multifocal leukoencephalopathy.
(39/512)
JC virus (JCV) induces progressive multifocal leukoencephalopathy (PML), especially in human immunodeficiency virus (HIV)-infected patients. Although JCV genotypes have primarily been associated with geographic patterns, a distinctive neuropathogenicity was recently attributed to genotype 2. A multicenter study was conducted to describe the distribution of JCV genotypes in France and to investigate correlations between genotypes and PML. Genotypes were determined by sequencing 494 bp in the VP1 capsid gene. Peripheral JCV was studied in 65 urine samples from 43 HIV-infected patients and from 22 control subjects. Genotypes 1, 4, 2, and 3 were detected in 52.3%, 30.8%, 12.3%, and 4.6% of the samples, respectively. In 56 brain or cerebrospinal fluid samples, PML-associated JCV of genotypes 1, 2, 4, and 3 was found in 66%, 19.7%, 8.9%, and 5.4%, respectively. Infection with JCV genotypes 1 or 2 was correlated with PML (odds ratio, 3.29). On the other hand, infection with JCV genotype 4 could represent a lower risk for PML. (+info)
Interaction of JC virus agno protein with T antigen modulates transcription and replication of the viral genome in glial cells.
(40/512)
In addition to encoding the structural and regulatory proteins, many viruses encode auxiliary proteins, some of which have been shown to play important roles in lytic and latent states of the viruses. The human neurotropic JC virus (JCV) genome encodes an auxiliary protein called Agno whose function remains unknown. Here, we investigated the functional role of JCV Agno protein on transcription and replication of the viral genome in glial cells. Results from transfection of human glial cells showed that Agno protein suppresses both T-antigen-mediated transcription of the viral late gene promoter and T-antigen-induced replication of viral DNA. Affinity chromatography and coimmunoprecipitation assays demonstrated that the Agno protein and T antigen physically interact with each other. Through the use of a series of deletion mutants, we demonstrated that the T-antigen-interacting region of Agno protein is localized to its amino-terminal half and the Agno-interacting domain of T antigen maps to its central portion. Furthermore, utilizing various Agno deletion mutants in functional studies, we confirmed the importance of the Agno-T antigen interaction in the observed down-modulation of T antigen function upon viral gene transcription and DNA replication by Agno protein. Taken together these data suggest that the Agno protein of JCV, which is produced late during the late phase of the lytic cycle, can physically and functionally interact with the viral early protein, T antigen, and downregulate viral gene expression and DNA replication. The importance of these observations in the lytic cycle of JCV is discussed. (+info)