Fig. 4.

Loss of αv from myeloid cells (but not lymphocytes) causes colitis. (a and b) Representative histology of colon (a), weight (b), and colitis score (b) of mice after bone marrow transplantation between 3-month-old αv-tie2 (KO) and control (WT) mice. Colitis was assessed a further 3 months after bone marrow transplantation. Note that transplantation of αv-deficient bone marrow (KO → WT) leads to colitis, whereas transplantation of control bone marrow is sufficient to reverse ongoing disease (WT → KO). (c and d) Representative histology of colon (c) and colitis score (d) from indicated αv-conditional knockout mice at 40–50 weeks of age. Deletion of αv from T cells (αv-lck) or from B cells (αv-CD19) does not lead to colitis, whereas deletion of αv from myeloid cells (αv-LysM) does. (e) Detail of colon (Upper) and mesentery (Lower) from 70 week-old αv-LysM mouse. Note ulceration in colon (*) and inflammation in mesentery. (f) Serum cytokine levels in 20-week-old αv-LysM mice. All graphs are mean ± SEM (n ≥ 4 mice per group). *, P < 0.05.