Natural Human Interferon‐γ Derived from Lipopolysaccharide‐stimulated Human Myelomonocytic HBL‐38 Cells

A human myelomonocytic cell line, HBL‐38 cells, propagated in vivo, spontaneously produced interferon (IFN)‐γ and IFN‐α. Whereas hemmagglutinating virus of Japan (HVJ) enhanced the production of IFN‐α, bacterial lipopolysaccharide (LPS) markedly enhanced the production of IFN‐γ. LPS could be replaced with lipid A. Furthermore, the enahancement of production of IFN‐γ by LPS was completely abolished by polymixin B. IFN‐γ derived from LPS‐stimulated HBL‐38 cells was purified to homogeneity and characterized. The apparent molecular weight, subspecies composition, amino acid sequence and glycosylated sites were in agreement with those of the product of normal human peripheral blood lymphocytes (PBL). These results indicate that the myelomonocytic HBL‐38 cells, not a T‐cell line, can also produce IFN‐γ identical to the product of normal human PBL.