Engagement of TREM2 by a novel monoclonal antibody induces activation of microglia and improves cognitive function in Alzheimer's disease models.

Genetic variants and mutations in triggering receptor expressed in myeloid cells (TREM2) are associated with premature and late onset Alzheimer’s disease (AD). We developed a panel of monoclonal antibodies, the selected lead of which was avidly shown to bind the extracellular domain of human and murine TREM2. By engaging membrane-bound TREM2, the selected antibody was shown to promote their cellular proliferation, uptake of oligomeric beta amyloid/apoptotic neurons, and activation in a Syk and Akt dependent manner. The antibody was shown to avidly bind soluble TREM2 in the CSF from AD patients and blunted the proinflammatory program driven by its intracerebral injection. Upon in vivo treatment, the antibody was shown to improve cognitive function in experimental amyloidopathy models and to facilitate plaque-associated microglial coverage and activation. Thus, we describe a novel monoclonal antibody targeting membrane bound and soluble TREM2, that improves cognitive function by inducing microglial activation and attenuating chronic neuroinflammation.