Multiple EBV-transformed B cell lines were established from five patients with a clinical diagnosis of Alzheimer's disease (AD) and six age-matched controls. The supernatants were screened for antibody activity against SDS-treated isolated neurofibrillary tangles (NFT). Reactive supernatants were identified from both the AD and control group. The frequencies of anti-NFT antibody-secreting lines were 6.3 and 1.6% for the AD and the control groups, respectively. A proportion of these supernatants also stained NFT in situ and neurons and/or glia in sections of the frontal and the temporal cortexes of autopsied AD and normal brains, as well as cells from three cell lines (HeLa, fibroblast, and neuroblastoma). Several patterns of staining were revealed by these supernatants, indicating different reactive antigens. One supernatant stained NFT and astrocytes in sections from AD brains. It did not stain sections from two normal brains. This cell line is the result of the immortalization of a circulating B cell making antibody specific for an antigen in AD. The present approach may provide new insights in the pathogenesis of AD.