In vivo Replication of Hamster Polyomavirus DNA Displays Lymphotropism in Hamsters Susceptible to Lymphoma Induction

1 Tumorgenetics, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13122 Berlin, Germany and 2 Medical Oncology and Tumorimmunology, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13122 Berlin, Germany Author for correspondence: Helmuth Prokoph. Fax +49 30 9406 3842, e-mail khaase{at}orion.rz.mdc-berlin.de Using the whole body section hybridization technique, we monitored the organ- and age-specific pattern of replication of hamster polyomavirus (HaPV) DNA in a colony of Syrian hamsters, which are susceptible to lymphoma induction. Three phases of viral infection and replication could be distinguished: first, a phase of acute infection characterized by high levels of replication of HaPV DNA in the haemopoietic organs and the liver. This culminated 5 to 7 days post-infection (p.i.); second, at 10 days p.i., a phase of viral clearance became evident; and finally, a third phase reflected both the restriction of HaPV replication in adult hamsters and the accumulation of HaPV DNA at sites of tumour development. A remarkable conformity was observed between the tissue specificity of viral replication and the induced tumour profile: high levels of replication of HaPV DNA were restricted to cells of the haemopoietic system and lymphoid tumours were induced. As shown by in situ hybridization, the viral infection in non-haemopoietic organs was due to the dissemination of HaPV-infected blood cells. Received 8 February 1996; accepted 17 May 1996.