To clone and express the truncated Habb mrp gene of human Streptococcus suis type 2 (S.suis 2) and detect its activity. A pair of primers based on S.suis 2 mrp gene were schemed out. The turncated mrp (tmrp)gene of S.suis 2 strain Habb isolated from diseased person in Haian, Jiangsu province was cloned and analyzed. The prokaryotic expression plasmid pGEX4T-2-tmrp was constructed.The expression of recombinant protein with glutathione S-transferase (GST) was induced in E.coli TG1. The fusion protein (tMRP-GST) was purified by affinity chromatography, and the GST was cut from tMRP-GST with thrombin protease to gain the truncated MRP (tMRP) antigen. The activity of recombinant protein was analyzed by Western blot. Sequence analysis showed that the length of the truncated mrp was 957 bp. The prokaryotic expressed production was a fusion protein, whose molecular weight was about 61 kD, and the molecular weight of the purified tMRP protein was about 35 kD. Western blot analysis showed that tMRP-GST and tMRP were de