BETA-AMYLOID(25-35) INDUCES THE PRODUCTION OF INTERLEUKIN-8 FROM HUMAN MONOCYTES

In an effort to unravel some of the cellular actions of beta-amyloid p rotein (A beta), we investigated its effects on interleukin-8 (IL-8) p roduction from human monocytes. Supernatants harvested from cultured m onocytes stimulated with the neurotoxic fragment 25-35 of beta-amyloid [A beta(25-35)] contained significant amounts of IL-8. Northern blot analysis demonstrated that A beta(25-35) also induced IL-8 mRNA accumu lation. The effect of AP(25-35) on IL-8 mRNA accumulation and secretio n was not mimicked by a scrambled A beta(25-35) peptide, and was not a ffected by polymyxin B sulphate, which, on the other hand, almost comp letely abolished the effect of lipopolysaccharide. Our results uncover a new biological action of beta-amyloid: that of stimulating the prod uction of a chemokine from monocytes.