Establishment and characterization of cell lines from Gross virus-induced rat leukemia.

Cells from thymus and/or bone marrow tissues of either normal or Gross virus-infected W/Fu rats were cultivated individually or mixed. Four continuous cell lines were obtained: 1) individual cultivation of the cells from thymic lymphoma, 2) combined cultivation of cells from thymic lymphoma and normal bone marrow, 3) bone marrow of a leukemic rat and normal thymus, and 4) bone marrow of a leukemic rat supplemented with cell-free extracts of normal thymus homogenates. The morphological features were similar in these 4 cell lines. The cell correspond morphologically to lymphoblasts, grow rapidly in suspension, and are transplantable in newborn rats. The cells release abundant Type-C virus particles. The inoculation of cell-free culture fluid into newborn rats resulted, after 7-9 weeks, in the development of thymic lymphoma in high incidence.