Histopathology of pulmonary lesions 4 weeks after <i>M. bovis</i> BCG infection.

<p>Wild-type mouse lung (A, E) shows small granulomas containing multinucleated giant cells, memTNF^Δ1–9,K11E KI mouse lung (B, F) shows larger granulomas compared with wild-type, also presenting multinucleated giant cells, and memTNF^Δ1–12 KI (C, G) and TNFR1/TNFR2−/− (D, H) mouse lungs exhibit large lesions containing numerous lymphocytes, neutrophils and monocytes, but lacking multinucleated giant cells. Regions of necrosis are observed in TNFR1/TNFR2−/− lungs. Figure is representative of two experiments (<i>n</i> = 6 per group). Magnification A–D 100× and E–H 400×.