Thus, lower AD risk may be associated with the ability of ApoE to dimerize and thereby promote apoER2 dimerization and signaling.<h4>Methods</h4>We examined calcium fluxes via the NMDA receptor in neurons derived from the NTera2 cell line in response to conditioned medium from human astrocytes differing in <i>APOE</i> genotype, recombinant ApoE proteins, reelin, amyloid β-peptide (Aβ) preparations differing in their aggregation states, and secreted amyloid precursor protein (sAPP). This evidence concerns the gene APOE and Alzheimer disease.