Transformation and Virus Production in Normal Rat Thymus Cells and Those Infected With Moloney Leukemia Virus

Summary

Cell lines T21M and T24M, derived from thymus cells of normal inbred Osborne-Mendel rats, were infected in vitro with Moloney leukemia virus (MLV). They have continuously produced virus for 3 years. Fluctuation in amount and brilliance of staining of the cells with fluoresceintagged rat anti-MLV antibody occurred. The T21M cell line grew as a reticulum cell sarcoma and fibrosarcoma on implantation into infant rats, whereas the T24M cell line did not transplant to infant rats. Cell lines T21C and T24C, derived from the same pools of normal rat thymus cells as used for T21M and T24M, were maintained as uninoculated control cell lines. Cell-free preparations from the cell lines produced no observable disease in BALB/c mice. The cell lines did not fluoresce with fluoresceintagged rat anti-MLV antibody. On implantation into infant rats the T21C cells occasionally formed tumors (fibrosarcoma and reticulum cell sarcoma) after a long latent period, while the T24C cells did not transplant to infant rats. An occasional C-type particle budded from the plasma membrane of these cell lines. The relationship of these particles to MLV particles is under study.