Figure 7.

CD8⁺ T cells infiltrate rejecting allogeneic tracheal grafts and Ab-mediated CD8⁺ T cell depletion reduces airway obliteration and fibrosis at Week 4 after allogeneic heterotopic tracheal transplant. Day 14 tracheal allografts were snap-frozen in liquid nitrogen and immunostained for CD8 (A) or isotype control Ab (B). Examples of extensive CD8⁺ infiltration of the subepithelia, lamina propria, and tracheal adventitia are marked by arrows. Scale bar in lower right corner = 50 μm. Anti-CD8 Ab (clone 2.43, rat IgG2b) was administered by tail vein injection at a dose of 1 mg per mouse at transplant and every 7 d thereafter, for a total of 4 doses. Mice were killed at Day 28 and H&E staining performed on tracheal grafts. A representative tracheal graft (n = 5 per group) from CD8⁺-depleted mice (C) and saline control (D) are shown.