OBJECTIVE:　To　prepare　the　polyclonal　antibody　of　the　extracellular　domain　(405T-573Q)　of　rat　Toll-like　receptor　2　(TLR2)　and　identify　its　activity.METHODS:　Firstly,　the　extracellular　domain　(507　bp)　of　rat　TLR2　was　amplified　from　rat　hepatocytes　by　reverse　transcription　PCR,　and　the　recombinant　plasmid　pET28a-TLR2ex　was　constructed.　Secondly,　the　fusion　protein　TLR2ex-6×His　was　expressed　in　E.coli　BL21(DE3)　and　purified　by　affinity　chromatography.　And　then,　the　polyclonal　antibody　was　prepared　by　immunizing　the　BALB/c　mice　with　the　purified　fusion　protein.　Finally,　the　titer　and　specificity　of　the　polyclonal　antibody　were　analyzed　by　ELISA　and　Western　blotting,　respectively.RESULTS:　The　recombinant　plasmid　pET28a-TLR2ex　was　successfully　constructed,　and　the　TLR2ex-6×His　fusion　protein　was　successfully　expressed　and　purified.　Western　blotting　demonstrated　that　the　antibody　from　the　TLR2ex-6×His-immunized　BALB/c　mice　specifically　and　selectively　bound　with　rat　TLR2.　ELISA　also　indicated　that　the　titer　of　polyclonal　antibody　reached　1:76　800.CONCLUSION:　The　polyclonal　antibody　against　the　extracellular　domain　(405T-573Q)　of　rat　TLR2　has　been　successfully　prepared.