TRALI induced by anti-CD36 led to upregulation of C5b-9 in the lungs and could be inhibited by administration of anti-C7. (A) Immunohistochemical detection of C5b-9 (MAC) in mice lung tissue from untreated wild-type mice (naïve) compared with LPS pretreated and received afterward mAb GZ1 (0.4 mg/kg) or isotype control, and pretreated with anti-C7 before GZ1 (n = 5 in each group). Lung tissue sections were stained with rabbit anti-C5b-9 (top panel) or normal rabbit IgG (normal IgG control, bottom panel), and images were taken at ×80 original magnification. Representative images from each indicated group are shown. Scale bars, 25 μm. (B) C5b-9 concentration in BALF of the indicated mouse groups were measured by enzyme-linked immunosorbent assay. In the prophylactic approach, anti-C7 (dose: 1 mg/200 μL in PBS; n = 5), or anti-C7 F(ab′)2 (dose: 1 mg/200 μL in PBS; n = 5) was administered before TRALI induction with mAb GZ1 (0.4 mg/kg). In the therapeutic approach, TRALI was first induced with mAb GZ1 (0.4 mg/kg), then mice were treated with anti-C7 (dose: 1 mg/200 μL in PBS; n = 10), or anti-C7 F(ab′)2 (dose: 1 mg/200 μL in PBS; n = 10) after TRALI. PBS was treated as a control. Rectal temperatures (C) and lung W/D weight ratios (D) were measured as described earlier. Statistical analysis was performed with 1-way analysis of variance with Bonferroni correction for multiple comparisons (B-D). Each dot represents 1 mouse and error bars represent the standard deviations. ∗∗∗∗P < .0001; ∗∗P < .01; ∗P < .05. ns, nonsignificant.
