Establishment and Characterization of Mouse Leukemia Cell Lines L615K and L7212K Derived from Transplantable Murine Leukemias Maintained in China

Two culture cell lines L615K and L7212K were established from transplanted murine leukemias L615 and L7212, which had been established and maintained in China for years. Based on morphological, immunological and gene rearrangement analyses, L7212K cells are considered to be of T‐cell origin while L615K cells might be immature T‐cells. Immunofluorescence assays of viable leukemia cells and fluorescence focus assays of their culture supernate for infectious viruses suggested that recombinant mink cell focus‐inducing viruses were significantly involved in both leukemic cell lines. Chromosome analysis of the L615K cells revealed a translocation t(12;17) which probably involved the c‐fos locus on chromosome 12, since the DNA rearrangement of c‐fos was demonstrated by Southern blot analysis with Hind III, and c‐fos has been assigned to this chromosome. Although the expression of this gene was not detected by RNA Northern blot analysis, c‐myc was slightly expressed in both L615K and L7212K cells.