TKT and Alzheimer disease: To study the different CNS populating myeloid cell populations in an AD-like environment, we crossed APPPS1+/− CD11b-HSVTK+/− mice to CX3CR1-GFP+/− mice to generate CX3CR1-GFP+/−APPPS1+/−CD11b-HSVTK+/− mice (Frac-GFP;APP+;TK+).