Figure 5.

Epithelial and stromal proteolytic activity associated with infiltrating cells. Serial sections of a region of inflammatory infiltrate from the colon of a CD4⁺ T-cell-transplanted SCID mouse (proximal segment, mouse 4). A and B: In situ zymograms, casein substrate, of area of infiltrate shown boxed in C. A: No inhibitors, showing substrate degradation associated with the epithelium (arrow) and the infiltrate (arrowheads). B: With cocktail of inhibitors blocking both serine proteases and MMPs, relative lack of substrate degradation. C–F: Indirect immunohistology showing distribution of CD3⁺ T cells (C), CD11b myeloid cells (D), F4/80⁺ myeloid cells (E), activated macrophages, mAb 158.2 (F). Original magnifications, ×128 (A and B); ×64 (C–F).