Microwave antigen retrieval of beta-amyloid precursor protein immunoreactivity.

Formalin fixation reduces beta-amyloid precursor protein (beta APP) immunoreactivity which restricts its study in archival tissue. Formic acid pretreatment has previously been used in an attempt to overcome this problem, but makes the sections very friable. In the present study, a microwave antigen retrieval method has been compared with formic acid pretreatment for retrieving beta APP immunoreactivity in formalin-fixed, paraffin-embedded human brain tissue. Microwave treatment resulted in superior retrieval of beta APP antigenicity in dystrophic neurites in Alzheimer's disease and in injured axons after head injury, using antibodies to three different epitopes. Unlike formic acid, microwave treatment causes minimal adverse effects on the strength and slide adhesion of the sections.