FIG 3.

Supporting evidence for MGAS2221 clearance by neutrophils in the lung. (A and B) Images of anti-F4/80 and anti-myeloperoxidase (MPO) immunohistochemistry staining of lung sections showing a few F4/80-positive macrophages (A) and numerous MPO-positive neutrophils (B) at the bronchial termini at 24 h after intratracheal MGAS2221 inoculation for the pulmonary infection samples in Fig. 1. The immunostaining had no hematoxylin counterstain. (C and D) Images of cytospin slides of BALF from experiments whose results appear in Fig. 2. (C) Numerous free GAS bacteria and the inability of resident macrophages (Φ) to phagocytose GAS in RB6-8C5-treated mice; (D) no free bacteria and GAS association with a small portion of neutrophils (PMN) in control mice.