Continuous production of minute virus of mice by an untransformed variant of Fisher rat fibroblast (FR3T3)

1 Unité d'Oncologie Moléculaire, Institut Pasteur de Lille, Centre National de la Recherche Scientifique URA 1160, BP 245, 59019 Lille Cedex, France 2 Département de Biologie Moléculaire, Université Libre de Bruxelles, rue des Chevaux 67, B-1640 Rhode St-Genese, Belgium and 3 Deutsches Krebsforschungszentrum, Abteilung 0610 and Unité INSERM 375, Im Neuenheimer Feld 242, D-69120 Heidelberg, Germany Many tumour cells are killed by the lytic replication of the autonomous parvoviruses H-1 and minute virus of mice (MVMp), whereas most untransformed cells (although they take up these viruses efficiently) are resistant, i.e. they do not produce infectious virus and are not lysed. Therefore, cells able to continuously produce large quantities of infectious virus have not yet been described. We have isolated such cells from the resistant cell line FR3T3 (Fisher rat fibroblast). These cells (called FR3T3C) produce infectious MVMp virions without being detectably lysed. Furthermore, a persistently infected population (R100FR3T3C) was generated by repetitive infection of FR3T3C cells with MVMp. Indeed, R100FR3T3C cells were successfully cultivated for two years and continuously produced infectious virus. Seventeen clones of R100FR3T3C cells isolated by limiting dilution produced infectious virions, indicating that in the R100FR3T3C cell population, virus production was not limited to a few cells. These cell lines may be useful for the production of MVMp and for the generation of a cell line for the packaging of recombinant viral genomes. * Author for correspondence. Present address: Laboratoire de Biologie Moléculaire et Cellulaire-Ecole Normale Supérieure de Lyon UMR 49 CNRS-ENS, 46 allée d'Italie, 69364 Lyon Cédex 07, France. Fax +33 72 72 80 80. e-mail Catherine.Koering@cri.ens-lyon.fr Received 8 August 1995; accepted 5 October 1995.