CD8A and Alzheimer disease: To confirm that GrK+CD103–CD8+ Trm cells directly induce neuronal dysfunction in AD, we used wide-field high-resolution microscopy for the live imaging of primary hippocampal neurons isolated from 3xTg-AD mice co-cultured with CD103– or CD103+ CD8+ Trm cells obtained from the livers of 3xTg-AD mice, an abundant source of CD8+ Trm cells36 (Fig. 4a).