Abstract: According to IL-15 gene sequence of Mus musculus available in GenBank database, specific primers were designed and synthesized. Using reverse transcription-polymerase chain reaction (RT-PCR) method, mature IL-15 sequence was amplified from the spleen cells of Kunming (KM) mice stimulated for 72 h by Toxoplasma gondii RH strain, then cloned into pMD18-T vector and transformed into the competent Escherichia coli JM109 for obtaining the positive clone and sequenced. Sequencing analysis revealed that the length of mature IL-15 of KM mice was 345 bp, encoding 114 amino acids. The results of sequence alignment and genetic evolution analysis showed that the KM mice mature IL-15 sequence was the closest to Norvegicus rattus, and the homologies of nucleotide and amino acid sequence were 94.2% and 95.5% respectively. Sequence similarity between the KM mice mature IL-15 sequence and that of Cavia porcellus, human, primates, Oryctolagus cuniculus, dog, cat, Bos taurus, Sus scrofa etc., and the nucleotide homology ranged between 71.2% to 78.8%, and the amino acid homology was 69.5% to 74.7%. The successful cloning of KM mouse IL-15 gene provided foundation for further studies of its functions and immune stimulating effects.

Key words: KM mice; IL-15; cloning; evolution analysis