Staining for CD26 expression on COS-7 cells transfected with CD26 deletion mutants by novel anti-CD26 mAbs. cDNA of deleted CD26 was cotransfected with GFP-expressing plasmid to COS-7 cells. After 24 h, the transfected cells were stained with Alexa Fluor 647-labeled anti-CD26 mAbs (YS110, clone 18 or clone 19) or isotype control, and analyzed by flow cytometry. Following gating for GFP positive cells among all acquired cells, the percentage of CD26 positive cells was analyzed. Data shown are repeated twice with similar results.