Immunophenotyping of Human T Cells in DRAGA Mice

Blood (50 µL) from tail vein was collected using heparin-coated capillary tubes, spun down, and erythrocytes were lysed with ACK buffer for 5 min in ice followed by a washed with 1% BSA in PBS. Splenocytes were isolated as previously described (19 (link)). Cells were blocked with anti-mouse Fc block (BD Biosciences) and surface stained with antibodies against human CD3 (#HIT3a), CD4 (#SK3), CD8 (#RPA-T8), CD69 (#L78), CD62L (#DREG-56), and CCR7/CD197 (#150503) from BD Biosciences as described (18 (link)–20 (link)). To evaluate the frequency of human CD4⁺FOXP3⁺ regulatory T cells in spleens of DRAGA mice, cells were first surface stained with human CD3, CD4 antibodies, and then intracellularly stained with a antibody against human FOXP3 (#236A/E7, Thermo Fisher Scientific) following the manufacturer’s instructions. Cells were analyzed in the gated mononuclear FSC/SSC as described previously (19 (link)).