Kinetics of the activation of immune markers in vivo in response to A. pleuropneumoniae infection. The concentrations of haptoglobin in plasma (A) and of IFN-γ in plasma (B) and BALF (C) were measured at 7 days before infection (-7) as well as at 4 and 21 days after infection. The box represents the 50% between 25% and 75% quartiles. The line inside the box indicates the median. The top and bottom lines denote the 5 and 95 percentile, whereas the black crosses denote minimum and maximum values. The numbers on the top of the boxes indicate the number of samples examined. ND – not determined; * p < 0.05; ** p < 0.01; *** p < 0.001.