Comodulation of CD26 with CD45RA in CBTCs. CD26, CD45RA, and CD45RO surface expression was determined by immunofluorescence as described in “Materials and methods.” PBTCs (A) and CBTCs (B) were analyzed for CD26, CD45RA, and CD45RO expression prior to and following incubation for the time periods indicated at 37°C with anti-CD26 mAb. Data are represented by histograms in which cells were stained with stated mAbs (thick lines) or isotype-matched mAbs (thin lines). The data are representative of 10 different donors.