Enhancement of O2− generation and tumoricidal activity of murine macrophages by a monosaccharide precursor of Escherichia coli lipid A

Abstract

The effects of a monosaccharide precursor of Escherichia coli lipid A (lipid X) on murine macrophages were studied. Lipid X is a diacylglucosamine 1‐phosphate bearing β‐hydroxymyristoyl groups at positions 2 and 3. Lipid X, as well as lipopolysaccharide and lipid A, enhanced O₂ ⁻ generation in mouse peritoneal macro‐phages and a macrophage‐like cell line, J774.1, and further induced the tumor‐cytotoxic activity of peritoneal macrophages. Elimination of a 1‐phosphate or 3‐O‐β‐hydroxymyristoyl group from lipid X completely abolished these effects, suggesting that both 1‐phosphate and 3‐O‐β‐hydroxymyristoyl groups are essential for the elevated O₂ ⁻ generation and induction of turmoricidal activity due to lipid X.