Investigation of the simian polyomavirus SV40 as a potential causative agent of human neurological disorders in AIDS patients.

Neurological diseases and a variety of neoplasms frequently occur in AIDS patients. Human JC and BK polyomaviruses have been associated with neurological disorders in such patients. SV40 polyomavirus sequences have been detected in human brain tumours, other neoplasms and normal tissues. JCV, BKV and SV40 DNA sequences were investigated in cerebrospinal fluid (CSF) samples from 12 AIDS patients affected by different neurological disorders, by PCR assay and filter hybridisation with specific internal oligoprobes, and DNA sequencing. Three of the 12 CSF samples were positive for JCV (one sample) or SV40 (one) DNA, or both (one). No sample was positive for BKV DNA. JCV- and SV40-specific genomic regions were confirmed by DNA sequencing. CSF samples from the two patients diagnosed clinically as having progressive multifocal leukoencephalopathy (PML) contained either JCV (one sample) or SV40 (one) DNA. The CSF found to contain both JCV and SV40 DNA originated from a patient with a cerebral mass lesion of unknown aetiology. These results suggest that SV40 may be involved in the aetiology of PML in AIDS patients, and raise the possibility that SV40 and JCV may act synergically in vivo to enhance their pathogenicity.

Simian-virus-40 footprints in human lymphoproliferative disorders of HIV- and HIV+ patients.

SV40 sequences were investigated by PCR DNA amplification followed by filter hybridization in a series of human lymphoproliferative disorders obtained from human-immunodeficiency-virus (HIV)-seronegative and HIV-infected patients. Our PCR and filter-hybridization conditions enabled us to detect SV40 sequences in the range of 10(-4) to 10(-2) genome equivalents per cell. In non-Hodgkin's lymphomas (NHL) from HIV- patients, SV40 footprints were found in 11 out of 79 (13.9%) samples, while in NHL from HIV+ patients SV40 DNA sequences were detected in 2/16 (12.5%). In Hodgkin's disease (HD), SV40 sequences were found in 7/43 (16.3%) and 1/12 (8.3%) in HIV- and HIV+ patients respectively. A slightly higher prevalence of SV40 footprints was observed in reactive lympho-adenopathies both in HIV- (3/9, 33.3%) and in HIV+ (6/17, 35.3%) patients. Sequence analysis of 2 NHL and 2 HD DNA samples established that the amplified PCR products belong to the SV40 sequences. SV40 prevalence and load were similar in samples from HIV-seronegative and HIV-infected individuals, suggesting that SV40 probably does not undergo strong reactivation phenomena in the context of HIV-related immunosuppression. Moreover, the large T-antigen(Tag) expression was detected by immunohistochemistry in 5/18 SV40-DNA-positive samples analyzed; however, few tumor cells (<1%) in 3/5 samples displayed positivity for SV40 Tag, while this viral oncoprotein was revealed in several reactive histiocytes present in all 5 SV40-positive tissues. These results suggest that the lymphoid tissue could represent a reservoir for SV40 and may constitute the first step in understanding whether this DNA tumor polyomavirus has a role in the pathogenesis of human lymphoproliferative disorders.

Simian virus 40 footprints in normal human tissues, brain and bone tumours of different histotypes.

SV40 footprints were investigated by PCR in normal human tissues and tumours of different histotypes, followed by Southern blot hybridization with a specific internal oligoprobe for SV40 DNA. Specific SV40 amplification products were detected at high prevalence in primary human brain tumours: 83% of choroid plexus papillomas, 75% ependymomas, 47% astrocytomas and 37% glioblastomas. SV40 footprints were also revealed in primary bone tumours: 35% osteosarcomas and Ewing's tumours. Positive normal tissue samples ranged from 45% of sperm fluids to 8% of brain tissue. Normal bone tissue specimens were SV40 negative. These results indicate that SV40 is associated with human brain and bone neoplasms, whereas normal bone and brain tissues were either SV40 negative or positive at low grade. SV40 footprints were found in other normal samples such as PBC, B- and T-lymphocytes and sperm fluids, indicating that SV40 is latent in these cells. Therefore, these cells may be vectors of SV40 in other host tissues and may spread SV40 infection by blood transfusion and sexual transmission in the human population.

SV40 early region and large T antigen in human brain tumors, peripheral blood cells, and sperm fluids from healthy individuals.

SV40 T antigen (Tag) coding sequences were detected by PCR amplification followed by Southern blot hybridization in human brain tumors and tumor cell lines, as well as in peripheral blood cells and sperm fluids of healthy donors. SV40 early region sequences were found in 83% of choroid plexus papillomas, 73% of ependymomas, 47% of astrocytomas, 33% of glioblastoma multiforme cases, 14% of meningiomas, 50% of glioblastoma cell lines, and 33% of astrocytoma cell lines and in 23% of peripheral blood cell samples and 45% of sperm fluids from normal individuals. None of the 13 normal brain tissues were positive for SV40 DNA, nor were seven oligodendrogliomas, two spongioblastomas, one neuroblastoma, one meningioma, or four neuroblastoma cell lines. Expression of SV40 early region was found by reverse transcription PCR, and SV40-specific Tag was detected by indirect immunofluorescence in glioblastoma cell lines. DNA sequence analysis, performed in four positive samples, confirmed that the amplified PCR products belong to the SV40 early region. Sixty-one % of the neoplastic patients positive for SV40 sequences had an age excluding exposure to SV40-contaminated polio vaccines, suggesting a contagious transmission of SV40. The possible role of SV40 Tag in the etiopathogenesis of human brain tumors and the spread of SV40 by horizontal infection in the human population are discussed.