Objective To study the interaction between ?_1-antichymotrypsin (ACT) and amyloid peptide A?_~1-42 in vitro, and the effects of their complex on expression of transcription factors PPAR? and NF?B in human neuroblastoma (Kelly) cells. Methods A?_~1-42 and ACT were mixed at a 10∶1 molar ratio at room temperature, the complex formed in 2 hours and 24 hours were expressed as A?_~1-42 /ACT (2 hours), A?_~1-42 /ACT (24 hours), respectively. The complexes were studied by using agrose electrophoresis, and their effects on PPAR? and NF?B expressions were assessed by electrophoresis mobility shift assay (EMSA). Results At conditions used, ACT interacted with A?_~1-42 in vitro, the complexes formed and functioned differently according to their interaction period. Compared with unstimulated control cells, A?_~1-42 /ACT (2 hours) strongly increased PPAR? and NF?B expressions by Kelly cells by 158% (P