title: Mason-Pfizer virus characterization: a similar virus in a human amniotic cell line.
abstract: Mason-Pfizer monkey virus (MP-MV) is a RNA virus with an RNA-instructed DNA polymerase first isolated from a rhesus monkey mammary adenocarcinoma in 1970. Until recently, there have been no other isolates. A continuous human amnion cell line, AO, was found to be producing a virus indistinguishable or closely related to the Mason-Pfizer virus as measured by morphological, immunological, and biochemical methods. By thin-section electron microscopy, the extracellular virus particle in AO line is 115 to 130 nm in diameter and has a preformed nucleoid (80 to 90 nm) before budding, properties which are also characteristic of MP-MV. Two proteins of the virus from the AO line were studied. By immunodiffusion, sera which react specifically with MP-MV give a line of identity with virus from the AO line. The AO viral RNA-instructed DNA polymerase purified by phosphocellulose chromatography was specifically inhibited by anti-MP-MV polymerase sera, and the AO cells contained both DNA and RNA sequences related to MP-MV (3)H-DNA. Viruses thus far indistinguishable from MP-MV have also recently been found by others in different human lines, raising again the question of the species of origin of MP-MV. Because the virus in the AO cells cannot be differentiated from MP-MV, we attempted to determine the origin of MP-MV virus by measuring DNA sequences related to MP-MV (3)H-DNA in uninfected human and rhesus monkey cells. The quantity of MP-MV-like DNA sequences in uninfected primate tissues was found to be much lower than the amount of DNA sequences of murine type-B or type-C viruses in uninfected murine tissues. Thus, it was not possible to determine whether the virus produced by AO cells or MP-MV was of human or monkey origin, or both.
mesh_terms: D000650:Amnion; D000956:Antigens, Viral / Q000032:analysis; D001483:Base Sequence; D002460:Cell Line; D002845:Chromatography; D004279:DNA, Viral / Q000032:analysis; D005455:Fluorescent Antibody Technique; D006801:Humans; D005779:Immunodiffusion; D008854:Microscopy, Electron; D009693:Nucleic Acid Hybridization; D009711:Nucleotides / Q000378:metabolism; D012328:RNA Viruses / Q000032:analysis / Q000201:enzymology / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*; D012367:RNA, Viral / Q000032:analysis; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D011863:Radioimmunoassay; D014316:Tritium; D014779:Virus Replication
chemical_list: D000956:Antigens, Viral; D004279:DNA, Viral; D009711:Nucleotides; D012367:RNA, Viral; D014316:Tritium; D012194:RNA-Directed DNA Polymerase