Fig. 2: Knock-down or neutralization of CD47 protects HBECs from viral–bacterial co-infection.

For CD47 knock-down, HBECs were transfected with scrambled shRNA (sc-shRNA) or shRNA targeting CD47 (CD47 shRNA) using a lentiviral delivery system. For CD47 neutralization, HBECs were treated with either IgG1 (MOPC-21) or α-hCD47 (B6H12.2) antibodies. a Gene expression of CD47 was analyzed using qRT-PCR (normalized by GAPDH mRNA) (sc-shRNA, n = 4; CD47 shRNA, n = 4). b Protein expression of CD47 was analyzed using immunoblotting (sc-shRNA, n = 5; CD47 shRNA, n = 5). c Paracellular FITC-dextran permeability was measured in Mock (n = 16), Virus only (IAV, n = 16), Bacteria only (S. aureus, n = 16), sc-shRNA + Super-infection (n = 12), CD47 shRNA + Super-infection (n = 6), IgG1 + Super-infection (n = 6), and α-hCD47 antibodies (Ab) + Super-infection (n = 8). d Trans-epithelial resistance was measured in Mock (n = 15), IAV (n = 14), S. aureus (n = 13), sc-shRNA + Super-infection (n = 13), CD47 shRNA + Super-infection (n = 6), IgG1 + Super-infection (n = 6), and α-hCD47 Ab + Super-infection (n = 8). e Microscopic images of HBECs at 5 dpi. The percentage of the damaged area is presented as bar graphs (Mock, n = 3; Virus only, n = 3; Bacteria only, n = 3; Super-infection, n = 4; IgG1 + Super-infection, n = 4; α-hCD47 Ab + Super-infection, n = 4). Data are presented as mean values ± SEM. Significance was determined by unpaired two-tailed Student’s t test or one-way ANOVA with Tukey’s multiple comparisons test. N.D. not determined. Source data are provided as a Source Data file.