Interleukin 1 production by a human acute monocytic leukemia cell line

Abstract

Human interleukin 1 (IL-1) was produced under serum-free conditions, by stimulating a human monocytic leukemia cell line (THP-1) with silica or lipopolysaccharide (LPS). The IL-1 from THP-1 cells has a molecular weight of 12,000–20,000, consistent with the low-molecular-weight form of IL-1 from human peripheral blood monocytes. Further characterization by isoelectro-focusing showed one major peak of activity at p I 7 for the THP-1 cell-derived IL-1. In contrast, the low-molecular-weight form of IL-1 from human monocytes has two major species, p I 5 and p I 7. This cloned THP-1 cell line produces levels of IL-1 activity comparable to those obtainable from peripheral blood monocytes. Thus THP-1 cells can serve as a valuable source of relatively homogenous human IL-1 for further purification and molecular characterization of its role in regulating immune functions.