The cell surface molecule expression by bone marrow mononuclear phagocytes (MP) after Actinobacillus pleuropneumoniae (APP) infection. The gating of MP subpopulations was performed as described in Figure 2. Representative dot-plots of CD172α (A), CD14, CD163 or MHCII versus CD172α (C) and CD14 versus CD163 (E) expression by MP are shown. The absolute counts of MP expressing CD172α (B), CD14, CD163 or MHCII versus CD172α (D) and CD14 versus CD163 (F) per mL of bone marrow were calculated (data are mean ± SEM). In the case of absolute counts of CD14 versus CD163 MP (F) the known counts of CD172α^hi/lo CD14^+/− and CD172α^hi/lo CD163^+/− (see Fig. 2F and Sect. 2), were used for calculations. Significant differences (p < 0.05) between noninfected (0 h after infection) and APP-infected piglets are marked with “a”. Significant differences (p < 0.05) between adjoining intervals are marked with “b”. (A color version of this figure is available online at www.vetres.org.)