CD274 and Alzheimer disease: Therefore, testing any immune checkpoint antibody in models of AD should be based first on the ability of the antibody to activate systemic immunity, and subsequently to improve cognitive performance, and only then be tested for its ability to reduce disease pathology26,30; measuring only plaque accumulation cannot serve as a primary read out, as the effect of anti-PD1/PDL-1 antibodies on the plaque load is secondary.