Inhibition or blockade of p80 function attenuates allograft dysfunction. In (A–D), wild-type C57BL/6J (C) or C57BL/6J IL-12 p40−/− (p40−/− C) donor tracheas underwent transplantation into wild-type BALB/cJ (B) or BALB/cJ IL-12 (Rβ1−/− B) mice. Additional cohorts of wild-type BALB/cJ recipients received IgG or anti–IL-12 p40 neutralizing antibody (α-p40 Ab, 1.0 mg administered intraperitoneally) every 4 d beginning 1 d before transplantation. At 14 or 28 d post-transplantation, grafts underwent H&E staining (A), quantification of the percentage of denuded BM (B), immune cell accumulation (C), and hydroxyproline (D) as described in Figure 1. Values represent means ± SEM (n = 4 or 5). *p < 0.05 compared with C → B.