CALCA and susceptibility to pneumonia measurement: This effect of APC was observed at 24 hours after inoculation of S. pneumoniae, while at the 48-hour time point neutrophil numbers in lungs and KC levels in lung homogenates and BALF were similar in both mouse strains, suggesting that during fulminant pneumonia the inhibitory effect of APC on neutrophil recruitment is overruled by the strong proinflammatory stimulus provided by high bacterial loads.