In situ detection of apolipoprotein E epsilon 4 in archival human brain.

A monoclonal antibody specific to apolipoprotein E 4 (apoE4) was applied immunohistochemically to archival human brain tissue. The examined 30 cases comprised four epsilon/epsilon4, 10 epsilon3/epsilon4, one epsilon2/epsilon4, 10 epsilon3/epsilon3 and five epsilon2/epsilon3 genotypes. The anti apoE4 antibody visualized senile plaques, neurofibrillary tangles and reactive astrocytes, as well as serum in the blood vessels and vascular smooth muscle cells in the cases of epsilon4. Moreover, the staining intensity was stronger in the cases carrying the epsilon4 homozygosity than in those cases of epsilon4 heterozygosity. Specific immunoreactivity was not obtained in those cases not carrying the epsilon4 allele. This method will allow in situ detection of apoE epsilon4 and contribute to studies of the effect of epsilon4 on Alzheimer's disease.