FIG. 4.

HDC^−/− mice exhibited a protective granulomatous response with a predominance of lymphocytic infiltrate upon M. tuberculosis infection. H&E-stained lung tissue from C57BL/6 (A and C) and HDC^−/− (B and D) mice was analyzed at 28 or 112 days after M. tuberculosis H37Rv infection, respectively. Formalin-fixed, paraffin-embedded lung tissue sections from mouse groups were also stained with the Ziehl-Neelsen acid-fast stain to detect mycobacteria (E and F). Arrows point to acid-fast bacilli. Sections shown are representative of the lungs of at least five animals per group. Original magnifications, ×50 (A to D) and ×640 (E and F).