CD8A and type 1 diabetes mellitus: When adding the unsorted CD4+ T cells from vehicle-, 1,25(OH)2D3-, or TX527-treated cultures to CFSE-labeled autologous PBMC responder cells in a standard suppression assay, a higher suppression of both CD4+ and CD8+ T cell populations was seen than with vehicle-treated cells, with similar effects in immune cells from control subjects or patients with type 1 diabetes (Fig. 5A).