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The preparation and therapeutic roles of scFv-Fc antibody against Staphylococcus aureus infection to control bovine mastitis

Wang, Man, Wang, Tingting, Guan, Yu, Wang, Fengqing, Zhu, Jianguo
Applied microbiology and biotechnology 2019 v.103 no.4 pp. 1703-1712
Escherichia coli, Staphylococcus aureus, Western blotting, antibodies, antigens, bacterial growth, bacteriophages, bovine mastitis, cattle, culture media, dairy industry, dose response, horseradish, immunoglobulin G, neutrophils, phagocytosis, therapeutics, vaccines
Staphylococcus aureus–induced bovine mastitis causes significant losses to the dairy industry and available vaccines do not confer adequate protection. As a more attractive alternative, we propose the use of antibody (Ab) therapy. In our previous study, we constructed a bovine single-chain variable fragment (scFv) Ab phage display and successfully obtained scFvs that bound to S. aureus antigens with high affinity. Here, we describe a novel Ab against S. aureus (scFv-Fc Ab). To construct the scFv-Fc Ab, the scFv Ab was genetically fused to the Fc fragment of a bovine IgG1 Ab. Western blot analysis showed that the bovine scFvs-Fc Abs were successfully expressed with horseradish peroxidase–conjugated goat-anti-bovine IgG (Fc) Ab in Escherichia coli cells. The purified bovine scFvs-Fc Abs had good binding activity to S. aureus and effectively inhibited the bacterial growth in culture medium and bovine scFvs-Fc Abs enhanced phagocytosis of S. aureus by neutrophils isolated from peripheral blood in a dose-dependent manner. In the experiment of bovine scFvs-Fc Abs for the treatment of S. aureus–induced bovine mastitis, the total effective percentage reached 82% (9/11). These novel bovine scFvs-Fc Abs may be useful as therapeutic candidates for the prevention and treatment of S. aureus–induced bovine mastitis.