Figure 4.

Human serum samples facilitate neutrophil-mediated killing of Staphylococcus aureus in vitro. A, Representative human serum samples demonstrating that serum samples are capable of facilitating neutrophil-mediated S. aureus killing (dotted lines represent serum and bacteria alone, demonstrating lack of direct serum toxicity; serum samples plus cells are required for killing). B, Human serum samples vary widely with regard to facilitation of neutrophil-mediated killing of S. aureus in vitro. C, No significant correlation exists between the ability of serum samples to facilitate S. aureus killing in vitro and serum activity after adoptive transfer and in vivo protection (colors indicate specific subjects as shown in B. Abbreviations: CFUs, colony-forming units; PMNs, polymorphonuclear leukocytes.