Viral carcinogenesis in a pronephric cell line. An ultrastructural study.

Herpesvirus recovered from cell fractions of the spontaneous Lucké renal tumor of adult Rana pipiens were used to infect a cell line derived from pronephroi of the same species. Viruses and virus-associated structures previously found in the primary renal tumor were observed, including nuclear inclusions of capsids with single or double membranes and capsids with nucleoids often within nuclear sacs. Embedded within the clumped and marginated chromatin were 55-nm tubular elements and associated unit membrane structures. Virus-associated, 35-nm tubular elements were also seen. The cytoplasm contained single, enveloped nucleoid virus and clusters of virus within cytoplasmic vesicles. Other cytoplasmic inclusions were dense, virus-associated, 25-nm filaments, virus particles within myeloid bodies, and possible viral budding from tubular organelles.