BACKGROUND: The induction of production and production inhibition of alpha1-antichymotrypsin (ACT), IL-1 alpha, IL-1 alpha receptor and macrophage inflammatory protein-1 (MIP-1) receptor in A beta1-42 (A beta)-stimulated U373MG cell, the human astrocytoma cell line, have never been reported. METHODS: U373MG cells (1 x 10(6) cells in RPMI-1640 media) were incubated for overnight after administration of a single dose of 20 micro M of A beta or 0.5 ng/ml of TNF alpha or both. Actinomycin D (2.5 micro M) or cycloheximide (2.5 micro M) was also added to the cell suspension. Messenger RNA expression of ACT, IL-1 alpha, IL-1 alpha receptor and MIP-1 receptor was measured by RT-PCR. Western blot was done and nitrocellulose paper was stained with anti-ACT and anti-GFAP antibody. NF kappa B activation after treatment of A beta in U373MG cells was detected by electrophoretic mobility-shift assay. RESULTS: A beta and TNF alpha both increased production of ACT in a dose-dependent manner. TNF alpha enhanced A beta-induced mRNA had increases of ACT, IL-1 alpha, IL-1 alpha receptor and MIP-1 alpha receptor. Activated NF kappa B was demonstrated in the A beta, TNF alpha-stimulated U373MG cells. Actinomycin suppresses mRNA level of ACT and IL-1 alpha receptor but cycloheximide inhibits the expression of ACT, IL-1 alpha and MIP-1 alpha receptor. CONCLUSIONS: TNF alpha increases synthesis of ACT, IL-1 alpha, IL-1 alpha receptor and MIP-1 alpha receptor in A beta-stimulated astrocyte, which, as a result, may contribute to the neuroinflammation of Alzheimer's disease.