The sequence of LukS-PV was amplified from PVL-positive Staphylococcus aureus isolates by PCR, and recombinant LukS-PV was generated as described previously.16 (link) Recombinant LukS-PV was purified using a His-Bind Purification Kit (Millipore, USA) and quantified using a BCA Kit (Beyotime, China).