Figure 5.

Neutrophil depletion during transgenic expression of interferon (IFN)-α partially decreases protection from pneumococcal infection. Female C57BL/6 mice were infected with 10⁷ plaque-forming units AdIFN-α and 48 hours later with 10⁴ colony-forming unit (cfu) of S. pneumoniae. In addition, 4 hours before Strep. infection, 50 µg of α-Ly6G depleting antibody or immunoglobulin G control was administered i.n.. (a) Average percent body weight change was monitored as an indicator of illness. (b) Lung and spleen bacterial load was measured using a CFU assay at 72-hour post-Strep infection. (c) Lung homogenates were measured for concentration of total of reactive oxygen species (ROS)/reactive nitrogen species (RNS) at 72-hour post-Strep infection. Results are from one experiment, n = 10–12/group. Data are expressed as mean ± SEM. *P < 0.05; ***P < 0.005.