Site of chemical modifications in CpG containing phosphorothioate oligodeoxynucleotide modulates its immunostimulatory activity

Phosphorothioate oligodeoxynucleotides containing CpG motifs have immunosti mulatory activity. Appropriate substitution of deoxynucleosides in the flan king region of CpG-containing phosphorothioate oligodeoxynucleotides with 2 '-O-methylribonucleosides results in significant decreases or increases in their immunostimulatory activities. The results provide insights in how to chemically modify phosphorothioate oligodeoxynucleotides containing CpG mot ifs to suppress or enhance their immunostimulatory activity for different t herapeutic uses. (C) 1999 Elsevier Science Ltd. All rights reserved.