TREM2 and Alzheimer disease: We used CRISPR/Cas9‐modified N9 microglial cell lines as well as bone marrow‐derived macrophages (BMDM) and primary microglia cells from wild‐type (wt) or Trem2 knockout (ko) mice and investigated the potential of these cells for antibody‐dependent phagocytosis of pre‐formed Aβ fibrils or engulfment of antibody covered amyloid plaques from brain cryosections obtained from a mouse model for AD pathology.