Different simian virus 40 genomic regions and sequences homologous with SV40 large T antigen in DNA of human brain and bone tumors and of leukocytes from blood donors

Simian virus 40 sequences in human lymphoblastoid B-cell lines

Human Epstein-Barr virus-immortalized lymphoblastoid B-cell lines tested positive by PCR for simian virus 40 (SV40) DNA (22 of 42 cell lines, 52.3%). B lymphocytes or tissues from which B-cell lines derived were also SV40 positive. In situ hybridization showed that SV40 DNA was present in the nucleus of a small fraction (1/250) of cells. SV40 T-antigen mRNA was detected by reverse transcription-PCR. Lymphoblastoid B-cell lines (n = 4) infected with SV40 remained SV40 positive for 4 to 6 months. SV40-positive B-cell lines were more tumorigenic in SCID mice than were SV40-negative cell lines (4 of 5 [80%] SV40-positive cell lines versus 2 of 4 [50%] SV40-negative cell lines). These results suggest that SV40 may play a role in the early phases of human lymphomagenesis.

Simian virus 40 sequences and expression of the viral large T antigen oncoprotein in human pleomorphic adenomas of parotid glands

Simian virus 40 (SV40) sequences of the early region coding for the large T antigen (Tag) oncoprotein were investigated in DNA samples from human pleomorphic adenoma (PA) of parotid glands. Specific SV40 sequences were detected, by PCR and filter hybridization with an internal oligoprobe, in 28 of 45 (62%) human PA specimens. None of the DNA samples from 11 normal salivary gland tissues was SV40-positive. DNA sequence analysis, carried out in all PCR amplified products from SV40-positive PA specimens, confirmed the SV40 specificity and indicated that PCR products had a sequence not distinguishable from SV40 DNA wild-type strain 776. SV40 Tag expression was revealed by immunohistochemistry with the specific monoclonal antibody Pab 101 in PA thin sections with a highly sensitive technical approach which retrieved the nuclear viral oncoprotein in 26 out of 28 (93%) samples previously found SV40-positive by PCR. Detection of SV40 sequences and Tag expression in human PA suggests that this oncogenic virus may play a role as a cofactor in the onset and/or progression of this benign neoplasm, or that SV40 DNA could replicate and express the Tag in PA cells.