The adaptive immune system restrains Alzheimer's disease pathogenesis by modulating microglial function

Area of Science:

• Immunology
• Neuroscience
• Alzheimer's Disease Research

Background:

• The innate immune system's role in Alzheimer's disease (AD) pathogenesis is established, but the adaptive immune system's involvement remains unclear.
• Despite this, T and B cell-targeting vaccination strategies are being explored for AD treatment.
• This study investigates the influence of adaptive immunity on AD pathogenesis.

Purpose of the Study:

• To determine the role of adaptive immunity in Alzheimer's disease (AD) pathogenesis.
• To investigate how the absence of T, B, and NK cells affects AD pathology in a mouse model.
• To explore the potential of adaptive immune cells in mitigating AD progression.

Main Methods:

• Generation of an immune-deficient AD mouse model (Rag-5xfAD) lacking T, B, and NK cells.
• Analysis of β-amyloid (Aβ) pathology, gene expression, and neuroinflammation markers.
• Bone marrow transplantation studies to assess the impact of adaptive immune cell reconstitution.

Main Results:

• Rag-5xfAD mice showed a twofold increase in Aβ pathology and exacerbated neuroinflammation.
• Gene expression revealed altered immune pathways, including reduced Ig-mediated processes.
• Restoring adaptive immunity via bone marrow transplantation significantly reduced AD pathology.

Conclusions:

• Adaptive immune cells, particularly T and B cells, play a critical role in restraining AD pathology.
• The absence of adaptive immunity leads to increased Aβ burden and neuroinflammation.
• Restoring adaptive immunity can reverse AD pathology, suggesting therapeutic potential.