Prokaryotic expression of Staphylococcus aureus ClfA and assay for its antisera bioactivity.

Gene of clumping factor A(ClfA) from Staphylococcus aureus(S.aureus)Shandong isolate ZFB1 amplified by polymerase chain reaction(PCR) was cloned into pGEX-6p-1 getting the recombinant pGEX/ClfA,and the ClfA was fused and coexpressed with GST.In order to get the antisera of ClfA,mice were immunized with the expressed protein,meanwhile,the bioactivity of antisera was detected by adherence inhibition assay.The SDS-PAGE and Western-blot analysis indicated that the fusion protein was 67 000 in molecular weight and had immunological activity.The antisera of expressed protein can inhibit adherence activity of S.aureus to cell surface by adherence inhibition assay.As protective antigen,ClfA protein can contribute to protect animals from the invasion,planting and infection.The study provides a theoretical base for the prevention of bovine S.aureus mastitis.