Effect of immunostimulatory CpG-oligonucleotides in chronic lymphocytic leukemia B cells

Bacterial DNA and phosphothioate oligonucleotides containing a CpG motif (CpG-ODN) can activate cells of the immune system such as monocytes, dendritic cells and B cells. Protective immune responses against pathogens and tumor cells were observed in murine models when mice were treated with CpG-ODN. Recent results have demonstrated strong activation of human immune cells as well. Apart from stimulating cells of the immune system, CpG ODN have many direct effects on B-CLL cells such as upregulation of costimulatory molecules, cell cycle entry and upregulation of potential target antigens for antibody therapy. Therefore, CpG-ODN appear to be attractive compounds to be included into new therapeutic strategies like tumor cell vaccination and adoptive T cell transfer or therapy with monoclonal antibodies. In this review, the effects of CpG-ODN on B-CLL cells are summarized and potential therapeutic applications of CpG-ODN in chronic lymphocytic leukemia are discussed.