Isolation of a SV40‐like papovavirus from a human glioblastoma

A human glioblastoma multiforme (M27) tested in early cell cultures by indirect immunofluorescence staining showed SV40‐related tumor (T)‐antigen, 95% of the cells being positive. SV40‐related viral capsid (V)‐antigen was absent in all cells tested. Experiments to rescue this virus were performed by fusing M27 cells with CV‐I monkey cells, which were permissive for SV40, using polyethylene glycol (PEG) as fusion factor. We succeeded in isolating virus particles SV40‐GBM which electron microscopy showed to correspond in size and morphology to papovaviruses. Serological tests (hemagglutination, neutralization, fluorescent antibody) revealed that the virus is indistinguishable from SV40. Despite this apparent antigenic identity SV40‐GBM differs slightly from SV40 wild type. This virus can propagate and produce CPE in both CV‐I cells and primary fetal human kidney cells. Furthermore digestion of SV40‐GBM DNA with the HindII/III restriction endonucleases revealed minor differences compared with the SV40 DNA. Therefore the virus SV40‐GBM obtained from glioblastoma cells seems to be closely related to the SV40‐PML viruses described earlier.