G-CSF blockade promotes the acceptance of lung allografts exposed to extended cold ischemia. (A) BM cells isolated from Ext CI Balb/c → B6 lung transplantations treated with control Ig or anti–G-CSF Ab 36 hours after engraftment and 2.5 × 10⁴ cells per plate were methylcellulose assayed for CFU-G, CFU-GM and CFU-GEMM numbers (n = 4; left). Neutrophil numbers in peripheral blood, lung tissue, and BAL from control Ig or anti–G-CSF Ab–treated Ext CI Balb/c → B6 transplantations 24 hours after engraftment (n = 4; right). (B) Analysis of PaO₂ (n = 5; left), exclusion of EBD (center); and histology (n = 5; right) after engraftment. (C) Percent abundance of intragraft IL-12⁺ I-A^d+ cells on POD 1 (n = 3; left), percent abundance of intragraft IFN-γ⁺CD4⁺ and IFN-γ⁺CD8⁺ T cells on POD 7 (n ≥ 4; center) and representative histology (n ≥ 4; right) on POD 7 from control Ig–treated, G-CSF Ab–treated, or Ly6G Ab–treated Ext CI Balb/c → B6 transplantations that received costimulatory blockade. (D) Ext CI Balb/c → B6 transplantations that received costimulatory blockade and IL-12–neutralizing Abs (n = 4) and assessed on POD 7 for the percentage abundance of intragraft IFN-γ⁺ CD4⁺ and IFN-γ⁺ CD8⁺ T cells (n = 4; left) and representative histology (n = 4; right) (E) Rejection scoring of lung grafts on POD 7 from costimulatory blockade-treated Ext CI Balb/c → B6 recipients that received control Ig, G-CSF, Ly6G, or IL-12 Abs. (F) Percent abundance of intragraft IFN-γ⁺CD4⁺ and IFN-γ⁺CD8⁺ T cells (n ≥ 3; left) and representative histology (n ≥ 3; right) on POD 7 from costimulatory blockade-treated Min CI Balb/c → B6 transplantations that received an IV injection of either 5 × 10⁵ Balb/c BMDCs (DC) or 5 × 10⁵ Balb/c BMDCs activated by coculture with BAL neutrophils from Ext CI B6 → B6 transplantations (DC: Neutrophil). (G) Percent abundance of intragraft IL-12⁺I-A^d+ cells on POD 1 (n = 3; left), percent abundance of intragraft IFN-γ⁺CD4⁺ and IFN-γ⁺CD8⁺ T cells (n = 4; center) on POD 7 and histology on POD 7 (n = 4; right) from costimulatory blockade–treated Min CI Balb/c → B6 transplantations that received mouse recombinant G-CSF (10 μg) immediately after reperfusion. (H) Rejection scoring on POD 7 for costimulatory blockade–treated Min CI Balb/c → B6 transplantations that received DCs, DC:Neutrophil, or G-CSF. Data for panels A, B, E, and H represent the means ± SEM. *P < .05; **P < .01.