Figure 3

NSG-A2-BLT mice develop lung lesions in response to BCG infection. Mice were infected as indicated in Figure 1, and sacrificed for histopathological examination. Lungs were inflated in 10% formalin, and embedded in paraffin for making thin sections. A. H&E stains on NSG-A2, NSG-A2-BLT, and C57BL/6 mice (100× and 20×, scale bars = 100 μm and 500 μm, respectively). Blue arrows indicate BCG lesions. B. Serial lung sections from NSG-A2-BLT mice infected with BCG were stained for H&E, Acid Fast bacilli, and immunohistochemistry for human CD68, human CD4, and human CD8. Immunostaining was visualized by colorimetric detection. Red arrows indicate BCG bacilli (200×, scale bars = 50 μm). C. Serial lung sections from NSG-A2-BLT and C57BL/6 mice infected with BCG were stained with human-specific antibodies against CD4, CD8, and CD68 followed by secondary antibody labeled with Alexa 555, and examined by fluorescence microscopy (200×, scale bar = 50 μm). Images are representative of tissues from four animals.