RBBP7 and Alzheimer disease: To elucidate the relationship between Rbbp7 and tau pathology, we first co-transfected an immortalized mouse hippocampal cell line (HT-22) with a plasmid expressing the familial AD mutant tau (TauP301L), as well as a human Rbbp7 (hRbbp7) plasmid, to assess cytotoxicity measured via MTT assay.