Rat pheochromocytoma PC12 cells are killed by amyloid beta protein (ABP), a component of plaques and other amyloid deposits in Alzheimer's disease. To investigate the possibility of protection from ABP toxicity by induced heat shock proteins (hsps), PC12 cells were heat treated for 60 min at 42 degrees C. The stress response of the PC12 cells was examined at the protein level using hsp72-specific monoclonal antibodies. Hsp72 immunoreactivity was highly induced following heat treatment. The toxic effect of the beta 25-35 ABP peptide fragment, the major cytotoxic sequence within ABP, was reduced in heat pretreated PC12 cultures. These data indicate a protective role of hsps in neuronal cells exposed to ABP.