DCs convey strong protection against antibody-mediated TRALI. (A) Representative flow cytometric dot plot analysis of splenocytes showing in vivo depletion of CD11chigh+ DCs (from 0.81% to 0.10% of total spleen cells) compared with isotype staining. (B) Representative macroscopic images of lungs from an in vivo DC-depleted mouse 90 minutes after injection of either a mouse immunoglobulin G2a (IgG2a) isotype control antibody (left) or 34-1-2s + AF6-88.8.8.3 (right). (C) Lung W/D weight ratios of WT C57BL/6 mice or CD11c-DTR mice that first underwent in vivo depletions of DC by the indicated injections (+) or not (−) of DT and were then injected with the TRALI-inducing antibody cocktail 34-1-2s + AF6-88.5.5.3 or indicated control antibodies. (D) Lung histology from naive WT C57BL/6 mice (subpanel A1-A2) and CD11c-DTR mice (subpanels B-E) receiving the indicated antibody injections. Subpanels A1-E1 and A2-E2 represent lung tissue images taken at original magnification ×20 and ×40, respectively. Representative images of each indicated group are shown. A zoom of indicated square in subpanel E2 (lung section from mice depleted of DCs and injected with 34-1-2s + AF6-88.5.5.3) is depicted and shows alveolar PMN infiltration. Scale bars represent 100 µM in subpanels A1-E1 and 50 µM in subpanels A2-E2. (E) Quasistatic lung compliance in DC-depleted CD11c-DTR mice that were injected (+) or not (−) with the indicated antibodies. All mice were analyzed 90 minutes after the second injection. For the statistical analyses, only significant comparisons of interest are shown. Panel C was analyzed with a 1-way ANOVA with a Tukey’s post hoc test, panel E was analyzed by a 1-tailed unpaired t test. Each dot represents 1 mouse, and error bars represent SD. ***P < .001, ****P < .0001.
