CHARACTERISTICS OF EPSTEIN-BARR-VIRUS TRANSFORMED B-CELL LINES FROM PATIENTS WITH ALZHEIMERS-DISEASE AND AGE-MATCHED CONTROLS

The characteristics of B cell lines isolated from patients with Alzhei mer's disease (AD) and age-matched controls were investigated after ha ving been transformed by Epstein-Barr virus (EBV). After isolation of mononuclear blood cells and in vivo or in vitro EBV infection, 35 and 21 lymphoblastoid cell lines (LCLs) were generated from 19 patients wi th AD (mean age 79.4 years) and 21 age-matched controls (mean age 80.0 years), respectively. B lymphocytes from AD patients were immortalise d more easily than those from controls; the percentage of in vitro EBV infected LCLs (B95-LCLs) obtained in the AD group was significantly h igher (76.2% versus 33.3% in the control group) and the mean time requ ired for establishment was significantly lower (20.2 and 21.9 days ver sus 26.7 and 60.9 days in the control group). The EBV receptor and sur face immunoglobulin (Ig) analyses showed no difference between the two groups. The expression of Epstein-Barr early antigens (EA) and viral capsid antigens (VCAs) revealed a tendency to higher viral replication in LCLs from AD patients; however, VCA expression remained limited to a small number of cells and did not affect overall cell growth. Final ly, qualitative and quantitative differences were observed in the patt ern of Ig production. Whereas spontaneously established LCLs from AD p atients were generally monoclonal (80% of LCLs versus 33% in the contr ol group), B95-LCLs were all polyclonal and secreted more IgM and IgA than those from controls; the mean IgM level was significantly higher in B95-LCLs from the AD group. These results suggest that B cells deri ved from AD patients seemed to be less differentiated than cells from age-matched controls.