Effect of oligodeoxynucleotides to β mRNA on the proliferation of Ba/F3-EpoR cells. Cells were cultured serum-free in the presence of 20 mmol/L antisense (•), sense (▪), nonsense (□) or positive control (○) oligonucleotides in the presence of Epo (A) or mIL-3 (B), and thymidine incorporation was measured on day 5. The results show that antisense oligonucleotides significantly reduces the growth of the cells compared with either sense or nonsense oligonucleotides.