Figure 5.

Immunosuppressive effects of adenosine contribute to S. aureus survival in blood. (A) Survival of adsA S. aureus Newman in mouse blood in the presence of increasing concentrations of adenosine (left) or guanosine (right) as indicated. Extracellular adenosine concentration was quantified by RP-HPLC immediately before enumerating bacterial CFUs, as described in Fig. S3. Data are representative of two independent analyses conducted in duplicate (left) and are representative of five independent analyses (right); error bars represent the SEM. (B) Growth of wild-type and adsA S. aureus Newman in laboratory growth media with 0–500 µM adenosine (Ado) for 15 and 45 min. Data are means of two independent analyses conducted in triplicate. Error bars represent the SEM. (C) Survival of wild-type, adsA, or adsA:padsA S. aureus Newman in human plasma. Data are averaged of two independent analyses conducted in triplicate; error bars indicate SEM. (D) The adsA gene is required for staphylococcal escape from neutrophil killing. Mouse blood was inoculated with S. aureus Newman expressing GFP, comparing the wild type (WT) and its isogenic adsA variant. At the indicated time points, samples were treated with 10 µg/ml⁻¹ lysostaphin, followed by isolation of neutrophils by FACS using anti-GR1 staining and phagocytosis and survival of staphylococci measured as mean GFP fluorescence. Data are representative of two independent analyses conducted in triplicate; error bars indicate SEM.