Immunotherapy of Alzheimer's disease (AD): From murine models to anti-amyloid beta (Aβ) human monoclonal antibodies

The deposition of amyloid beta (Aβ) protein is a key pathological feature in Alzheimer's disease (AD). In murine models of AD, both active and passive immunization against Aβ induce a marked reduction in amyloid brain burden and an improvement in cognitive functions. Preliminary results of a prematurely terminated clinical trial where AD patients were actively vaccinated with aggregated Aβ bear resemblance to those documented in murine models. Passive immunization of AD patients with anti-Aβ antibodies, in particular human antibodies, is a strategy that provides a more cautious management and control of any undesired side effects. Sera of all healthy adults contain anti-Aβ IgG autoimmune antibodies. Hence antigen-committed human B-cells are easily immortalized by Epstein-Barr virus (EBV) into anti-Aβ secreting cell lines. Two anti-Aβ human monoclonal antibodies which we recently prepared bind to the N-terminus of Aβ peptide and were shown to stain amyloid plaques in non-fixed brain sections from an AD patient. It is anticipated that specifically selected anti-Aβ human monoclonal antibodies could reduce and inhibit deposits of amyloid in brain while avoiding the cognitive decline that characterizes AD. In the future, this type of antibody may prove to be a promising immune therapy for the disease.