CXCL12 intensity score in mesothelial cells.

The visceral pleural mesothelium from infected (inf.) and naive C57BL/6 and BALB/c mice was stained for CXCL12 (polyclonal antibody, 1∶500, eBioscience; and biotinylated monoclonal 1∶200, clone K15C). Four animals were studied for each condition (6 groups: naive BALB/c, naive C57BL/6, infected BALB/c, infected C57BL/6, infected and C04 or AMD3100-treated BALB/c and C57BL/6). 8 to 17 whole sections of pulmonary lobes were analyzed by light microscopy and discriminated according to the intensity of CXCL12 staining in 3 categories: no detectable staining (Neg.), intermediate (Int.) or high intensity (High). The level of CXCL12 was arbitrarily scored as 0 (no detectable staining), 5 (intermediate staining), and 10 (high staining). A mean score (weighted mean) per section of pulmonary lobe was calculated according to the coefficient defined previously.