SENSITIVITY OF THE TRANSMISSIBLE GREEN TURTLE FIBROPAPILLOMATOSIS AGENT TO CHLOROFORM AND ULTRACENTRIFUGATION CONDITIONS

Transmission experiments were conducted to further characterize the fi lterable transmissible agent that causes GTFP, fibropapillomatosis of green turtles Chelonia mydas. Cell-free homogenates (unfiltered or 0.4 5 mu m filtered), prepared from fibropapillomas of free-ranging green turtles (donors) and inoculated into 18 captive-reared recipients, ind uced tumors in recipients with an overall success rate of 83.3% (range : 0 to 100%). Chloroform treatment prior to inoculation destroyed tumo rigenic activity of these homogenates. These data are consistent with the hypothesis that the GTFP agent contains a lipid component, such as a viral envelope, necessary for tumorigenicity. Ultracentrifugation o f tumor homogenates for 2 h at 100 000 x g cleared the supernatant of tumorigenic activity. Tumorigenicity was recovered in the ultracentrif uge pellet. The pellet, however,was less effective at inducing tumors than the starting material, indicating that the GTFP agent was damaged by these ultracentrifugation conditions. The possibility that the GTF P-associated herpes virus is the etiologic agent of GTFP was further s upported by the observation of eosinophilic intranuclear inclusions in 24.3% of experimentally induced tumors in this study. Tumorigenic act ivity survived storage for several months at -80 degrees C and at leas t 1 yr at -180 degrees C, making it feasible to isolate the GTFP agent and its genome from frozen archived material once methods have been o ptimized.