In this study, we addressed the role of a congenital deficiency of the adaptive immune system on β-amyloid-related pathology in vivo and generated B and T cell-ablated APP transgenic mice by crossbreeding the PSAPP mice, en established mouse model of Alzheimer’s disease [36], with the recombination activating gene-2 knockout (Rag2 ko) mice lacking functional B and T lymphocytes [37]. Here, APP is linked to early-onset autosomal dominant Alzheimer disease.