S100A9 and infection: In nu/nu mice, there was no difference in serum concentration of MRP8 (naïve: 135.4 ± 72.5 ng/ml, Pb-infected: 151.3 ± 72.3 ng/ml) and MRP14 (naïve: 2.1 ± 0.4 μg/ml, Pb-infected: 2.1 ± 0.7 μg/ml) between naïve mice and Pb-infected mice (Fig 2A), while serum concentration of MRP8 and MRP14 was significantly higher after Pb-infection in WT mice (naïve: 30.9 ± 15.4 ng/ml, Pb-infected: 315.2 ± 93.5 ng/ml for MRP8; naïve: 0.06 ± 0.04 μg/ml, Pb-infected: 3.8 ± 0.6 μg/ml for MRP14).