Effect of IK antisense oligonucleotides on HLA-DR and CD34 antigen expression by cord blood CD34⁺ cells. Isolated CD34⁺ cells were cultured in IMDM containing 5% FCS and a combination of 3 cytokines, IL-1, IL-3, and SCF, in the presence of IK antisense or control oligonucleotides. After 7 days of culture, cells were collected and stained either with antihuman FITC-conjugated anti-HLA-DR MoAb or PE-conjugated anti-CD34⁺ MoAb (━) or with negative control antibodies (─). (A and E) Freshly isolated CD34⁺ cells (day 0) CD34⁺ cells cultured for 7 days either in the absence of oligonucleotide (B and F ) or in the presence of control (20 μmol/L) (C and G) or antisense (20 μmol/L) (D and H) oligonucleotides.