SPP1 and infection: At 72 h after infection, pulmonary OPN levels were still elevated, which together with the higher bacterial load might have contributed to the increased neutrophil numbers in lungs of WT mice; in addition, although early neutrophil recruitment is essential for resistance to B. pseudomallei infection [12], neutrophils can act as a “double-edged sword” and damage the architecture of lung tissue [40], [41], a mechanism that likely contributed to the enhanced lung injury in WT mice.