Abstract: Specific primers for bovine IL-2 (BoIL-2) cDNA were designed and synthesized according to the previously published sequence in GenBank. The total cell RNA, isolated from ConA-stimulated peripheral blood lymphocyte of bovine, was used as template to generate complementary DNA by reverse transcription. The DNA fragments were amplified by polymerase chain reaction (PCR) and digestion, and cloned into the pMD18-T vector. The fragment was confirmed bovine interleukin-2 by DNA sequencing. The sequence analysis showed that it was similar to the sequence of bovine IL-2 publised in GenBank, the homology was 98.7% in nucleotide acid. Then the prokaryotic expression plasmid pET30a/rBoIL-2 was constructed and transformed into BL21 cell. The recombinant rBoIL-2 was expressed efficiently in forms of inclusion body. SDS-PAGE and Western blotting analysis showed that the recombinant fusion protein had a molecular weight 23.49 ku. The inclusion body was purified by QIAGEN Ni-NTA resin. The protein was purified and used to immunize rabbit, and polyconal antibody was prepared. The preparation of its polyclonal antibody will provide solid basis for the biological activity study and application of BoIL-2.

Key words: interleukin-2; expression; polyclonal antibody