FIG. 5.

Effect of exogenous TNF-α on the granulomatous response in the lungs. Mice were infected with M. tuberculosis and treated intranasally with recombinant murine TNF-α, and the lungs were examined at 4 weeks postinfection. (A to C) Untreated mice. (D to F) TNF-α-treated mice. Note extensive lymphocyte infiltration in arrows (A) and Ly (C). In response to TNF-α treatment (E), large macrophages are present in the alveolar spaces (arrowheads). Hematoxylin and eosin stain. (A and D) Magnification, ×4. (B, C, E, and F) Magnification, ×40.