NOS2 and infection: iNOS mRNA was hardly expressed in uninfected wild-type Hoxb8 neutrophils (μ = Ct 39.4, SD = Ct 1.7, 7 experiments), but was 100- to 1000-fold induced upon infection or LPS-stimulation at the time points 24–96 h (U = 0, n1 = n2 = 7, P = 0.0006 at 24 and 48 h p.i., Additional file 1: Figure S1g).