Genetic deletion of the α₁ subunit of the murine α₁β₁ integrin protects mice against DSS-induced colitis. Colitis was induced in either BALB/c WT or α₁-deficient BALB/c mice as described in Figure 1 legend. Disease severity was measured daily and is noted in terms of (a) body weight, (b) fecal blood, (c) diarrhea, and (d) disease activity index (combined index of a + b + c). α₁^–/– mice exhibited similar protection to that observed in mice treated with the function-blocking anti-α₁ mAb (compare with Figure 1). *P < 0.05, α₁^–/– vs. WT. Data represent mean ± SEM.