Effects of Cytokines from Virus-Induced Human Lymphoblasts on the Growth and Viability of the Promyelocytic Leukemia Cell Line HL-60

Cells of the human B-cell lymphoblastic leukemia line, BALL-1, were stimulated with Sendai virus. It is shown that the crude culture supernatants contain not only interferon-α (IFN-α) and tumor necrosis factor-α (TNF-α) but also other cytokines, here collectively termed 'X' cytokines. The latter did not affect the cytostatic or differentiation-inducing effect of IFN-α but synergistically increased the cytotoxicity of TNF-α.