Leukemia-derived growth factor (non-interleukin-2) produced by murine lymphoma T-cell lines

Autocrine growth factor activity was found in supernatants of AKR T-cell lymphoma lines cultured in serum-free medium. This factor was designated leukemia-derived growth factor (LDGF). Active supernatants stimulated the growth of the AKR murine T-cell lymphoma line SL 12, its cloned derivatives, and all other murine T-cell lymphoma lines tested. Growth factor activity in conditioned medium was found to be different from interleukin 2 (IL-2) and several other known growth factors. LDGF was able to stimulate growth of the human leukemia T-cells MOLT4f, and the LDGF from MOLT4f cells stimulated the mouse cells. Because mouse T-cell lymphoma lines produced and respond to this factor, it may support the continued proliferation of these cells and could be responsible for their malignant in vivo properties.