Oncogenic herpesvirus DNA absence in kidney cell lines established from the northern leopard frog Rana pipiens

Abstract

The etiological agent of the Lucke renal adenocarcinoma of the northern leopard frog Rana pipiens is the Lucke tumor herpesvirus (LTV). LTV can be detected with the electron microscope in thin sections of spontaneous tumors from frogs that have been exposed to a cold environment. No viruses can be detected with the electron microscope in spontaneous tumors of frogs maintained under warm conditions even though the 'virus-free' (warm) tumors contain latent LTV. Because electron microscopy is an insufficient procedure to detect the oncogenic herpesvirus during its latent phase and because we sought to ascertain whether the virus is present in cells which do not manifest electron microscope-detectable viruses, we developed a polymerase chain reaction (PCR) procedure to amplify a Hind III fragment of the viral DNA, JH12. While all warm, 'virus-free', spontaneous kidney tumors studied thus far contain this restriction enzyme fragment of LTV DNA, we report here that we failed to detect JH12 DNA in the tumor-derived cell line PNKT-4B. A normal frog cell line, WMPA, similarly failed to exhibit the restriction enzyme fragment of LTV DNA.