Lymphokine mediated production of an epidermal cell proliferation factor by cultured murine bone marrow cells

The effect of cultured bone marrow cell supernatant (BMS) was studied on the proliferative response of cells of the transformed murine epidermal cell line Pam 212. Elevated DNA synthesis was found in Pam 212 cells cultured with BMS from bone marrow cells grown in spleen cell conditioned medium with concanavalin A (ConA). Pam cell proliferative activity was related to the histamine content in the culture supernatant. Neither spleen cell conditioned medium with IL1, IL2, or IL3 activity, nor ConA alone, showed any effect on Pam cell growth. A soluble mediator from the cultured bone marrow cells with mast cell characteristics was thought to be responsible for the stimulation of Pam cell growth, and Con A appeared to be a prerequisite for generation of this factor by the bone marrow cells.