Graduation Year


Document Type




Degree Granting Department

Pharmacology and Therapeutics

Major Professor

David Morgan Ph.D.


Immunization, Transgenic mice, Inflammation, Alzheimers disease


Alzheimers disease (AD) is defined as a progressive neurodegenerative disorder that gradually destroys a persons memory and ability to learn. There are three pathological hallmarks of the disease which are necessary for diagnosis of AD, these are; extracellular amyloid plaques composed of [beta]-amyloid (A[beta]) protein, intracellular neurofibrillary tangles and neuronal loss. Amyloid plaques exist as both compact deposits which stain with Congo red and more numerous diffuse deposits. Active immunization against A[beta] 1-42 or passive immunization with monoclonal anti-A[beta] antibodies reduces amyloid deposition and improves cognition in APP transgenic mice.Over several studies of active immunization in APP+PS1 transgenic mice we showed a strong correlation between reduction of compact amyloid deposits and the degree of microglial activation suggesting a potential role of microglia in the removal of A[beta].

Injection of anti-A[beta] antibodies into the frontal cortex and hippocampus of aged APP transgenic mice revealed an early phase of A[beta] removal which was removal of only diffuse amyloid deposits with no associated activation of microglia. A later phase was the removal of compact amyloid deposits. This was associated with significant activation of microglia. Prevention of this microglial activation by anti-A[beta] F(ab)2 fragments or its inhibition by dexamethasone also precluded the removal of compact amyloid deposits but did not affect the removal of the diffuse deposits. Systemic injection of anti-A[beta] antibodies weekly over a period of 1, 2, 3 and 5 months transiently activated microglia associated with the removal of compact amyloid deposits and elevated plasma A[beta], suggesting a peripheral mechanism contributes to removal of brain A[beta].