Recognition of normal nonhematopoietic cells by LB-ADIR-1F–specific CTLs. Recognition of LB-ADIR-1F–expressing HLA-A2–positive MSCs (A,C) and BECs (B,D) by CTL RDR2 was studied in 3 separate 4-hour ⁵¹Cr release assays and in 3 separate IFN-γ secretion assays. Lysis of untreated target cells (□) and target cells exogeneously pulsed with saturating concentrations of synthetic peptide (▪) was compared with lysis of patient EBV-LCLs (▵) (A,B). IFN-γ secretion by CTL RDR2 was measured after 24 hours of cocultivating CTL RDR2 at a 3:1 responder-stimulator ratio with untreated cells, peptide-pulsed cells, and patient EBV-LCLs (C,D). Data are shown as mean values ± SD.