The primary goal of this study is to evaluate the effect of PF-04360365 on the clearance of ABETA from the CSF (cerebrospinal fluid) in patients with mild Alzheimer's disease and healthy volunteers. Additionally, the study will assess the pharmacokinetics of PF-04360365, pharmacokinetic and pharmacodynamic relationships in plasma and CSF and the safety and tolerability of single doses of PF-04360365 administered to patients with Alzheimer's disease and healthy volunteers.

Inclusion Criteria:

• Males or females of non-childbearing potential (age 50 and over for Alzheimer's disease patients; 21-45 for healthy volunteers)
• For patients with Alzheimer's Disease: Diagnosis of probable Alzheimer's disease, consistent with criteria from both National Institute of Neurological and Communicable Disease and Stroke and Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) and Diagnostic and Statistical Manual of Mental Disorders (DSM IV)
• Mini-mental status exam score greater than or equal to 20
• Rosen-Modified Hachinski Ischemia Score of < or = 4
• On stable dose of background cholinesterase inhibitor or memantine at least 3 months prior to enrollment

Exclusion Criteria:

• Diagnosis or history of other demential or neurodegenerative disorders
• Diagnosis or history of clinically significant cerebrovascular disease
• Specific findings on magnetic resonance imaging (MRI); cortical infarct, micro hemorrhage, multiple white matter lacunes, extensive white matter abnormalities
• History of autoimmune disorders
• History of allergic or anaphylactic reactions