Immortalized human T cell lines were established by cotransfecting c-H
a-ras and c-myc oncogenes to lymph node lymphocytes. The cell lines ke
pt growing for 3 months after establishment without a decrease in grow
th rate. The cells did not require interleukin-2 (IL-2) for their grow
th, but addition of IL-2 stimulated the growth of these cells. Flow cy
tometric analysis revealed that these cells were T cells expressing CD
4 or CD8 antigens. A CD4 positive (CD4+) cell line produced IL-6, indi
cating that the cell line belongs to helper T cells. The CD8 positive
(CD8+) cell line possessed cytotoxicity to tumor cells, indicating tha
t the cell line were killer T cells. Both cell lines were able to prol
iferate in serum-free medium indefinitely.