Anti-CD18 antibody neutralizes Am80-enhanced neutrophil bactericidal activities. (A) Effects of anti-CD18 antibody on neutralization of AINs, GINs, and PBNs phagocytic and bactericidal activities against E coli (**GINs versus AINs without Abs, P < .037 at least; *AINs versus AINs+Abs, P < .036 at least; GINs versus GINs+Abs, P < .006 at least; PBNs versus PBNs+Abs, P < .007 at least). Abs indicates antibodies. (B) In situ bacterial killing imaged by confocal microscopy. White arrow indicates surviving (green) or dead bacteria (red), whereas black arrow indicates example of neutrophil nucleus stained in red simultaneously by PI fluorescent dye. (C) Quantification of both extracellular bacteria after infection and in situ killed bacteria in panel B (**GINs versus AINs or PBNs, P < .006 at least; *AINs+IgG versus AINs+Abs, P < .008; PBNs+IgG versus PBNs+Abs, P < .03). (D-E) Effects of anti-CD18 antibody on neutralization of AINs, GINs, and PBNs phagocytic and bactericidal activities against S aureus (**GINs versus AINs or PBNs, P < .03 at least; *AINs+IgG versus AINs+Abs, P < .007 at least; PBNs+IgG versus PBNs+Abs, P < .02 at least).