Fig 5. Decreased macrophage recruitment to pulmonary BALT in β₂m^-/- mice.

β₂m^-/- mice or C57BL/6 controls were footpad-infected with O. tsutsugamushi. 16 or 17 days p.i., mice were sacrificed. A, Consecutive lung sections, stained for IBA1 or iNOS (top, middle) and cryosections, stained for IBA1 (green) and DAPI (blue) (bottom). Arrowheads indicate IBA1+ or iNOS+ cells in BALT regions (immunohistochemistry) or IBA1+ cells at peribronchial lining (immune fluorescence). Scale bars, parenchyma: 100 μm; BALT: 200 μm. Images show representative regions. Graphs show percentages of stain⁺ areas per total tissue area from 4 representative regions of each mouse (n = 3). β₂m^-/- were compared to C57BL/6 controls by two-way ANOVA with Bonferroni’s posttest. ns: not significant; *** p<0.001 B, Immunofluorescence of bronchiolar lining, stained with antibody against the O. tsutsugamushi 56 kD antigen (red) and DAPI (blue) overlayed with DIC. Images were captured with an Olympus confocal microscope. Bottom panel shows region of higher magnification. Arrowhead indicates a bacterium at the luminal side inside an epithelial cell. Scale bars: 100 μm (overview); 20 μm (detail). parench.: parenchyma.