Plasma

The purpose of this study is to see how safe LY4560736 is and to see how much and how quickly LY4560736 gets into the bloodstream. For healthy participants, the study also looks at how much LY4560736 gets into the brain. This part of the study lasts up to 13 weeks which includes staying in the Clinical Research Unit (CRU) for at least 4 days. This group will include Japanese participants, and the Sponsor may choose to enroll Chinese participants. For participants with Alzheimer's Disease, the study will also look at levels of a specific Alzheimer's-related protein in the brain and will last up to 13 weeks which includes staying in the CRU twice, each lasts about 1 to 2 days. Japanese participants, and potentially Chinese participants, may also be enrolled in this group.

This study will evaluate the clinical performance of two investigational diagnostic kits developed by ALPCO: the Syphilis-T CLIA Kit and the Syphilis-NT CLIA Kit. These kits are designed to detect antibodies to Treponema pallidum and non-treponemal lipoidal antigens, respectively, in human serum and plasma using the automated KleeYa platform. The study will collect and analyze blood samples from individuals suspected of having syphilis, those at high risk, HIV-positive patients, pregnant individuals, and healthy controls. The aim is to determine the kits' Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) compared to established reference assays.