The invention relates to oligonucleotides including at least one backbone modification and a pyrimidine-purine dinucleotide. The invention also relates to pharmaceutical compositions and methods of use thereof.本發明係關於包括至少一個主鏈修飾及嘧啶-嘌呤二核苷酸之寡核苷酸。本發明亦係關於醫藥組合物及其使用方法。