Fig. 4. CD11b⁺ neutrophils accumulate in the lung of infected animals with severe disease.

a Fluorescent immunohistochemistry in the lung of AGM and RM showing infiltration of MPO⁺ neutrophils and MPO⁺ CD11b⁺ neutrophils. MPO and CD11b staining. White: DAPI (nuclei); green: CD11b; red: MPO. The number of MPO positive cells (red, arrows) increases in proportion to the severity of pulmonary disease from rare in the control (HK11), to mild in FR04, moderate in GH99 and severe in NC34. Dual positive MPO⁺ CD11b⁺ positive cells (arrowheads) are present in the most severely affected animals (NC34). b Mean and number of MPO⁺ cells, each dot is one count the standard deviation represents variability in the number of positive cells/area and c and MPO⁺ CD11b⁺ per mm² in lung necropsy.