DSS-induced colitis results in accumulation of granulocytes/monocytes that is significantly inhibited by treatment with anti-α₁ mAb. Immunohistochemical staining of colonic cross sections from WT mice receiving either regular water (a and e) or mice that were treated for 7 days with DSS in the absence (b, d, f, and h) or presence (c and g) of anti-α₁ mAb. Dual immunofluorescent staining of colon tissue was performed with Alexa 488–conjugated anti-α₁ mAb and either PE-conjugated anti-CD3 mAb (a–d) or anti-CD11b mAb (e–h). PE-conjugated mAb’s were specific for granulocytes/monocytes (anti-CD11b) and T lymphocytes (anti-CD3). No staining was seen with Alexa 488– and PE-conjugated isotype control mAb’s (not shown). In a–c and e–g, magnification is ×100 and bar represents 100 μm. In d and h, magnification is ×400 and bar represents 25 μm.