Triggering receptor expressed on myeloid cells 2 (TREM2) plays a crucial role in regulating microglial functions and removal of amyloid plaques in Alzheimer's disease (AD). However, therapeutics based on this knowledge have not been developed due to the low antibody brain penetration and weak TREM2 activation. In this study, we engineered a TREM2 bispecific antibody to potently activate TREM2 and enter the brain. To boost TREM2 activation, we increased the valency of bivalent anti-TREM2 Ab2 IgG ...