Antibodies raised against N'-terminal Pseudomonas aeruginosa flagellin prevent mortality in lethal murine models of infection.

The goal of this study was to investigate if antibodies raised against N'-terminal Pseudomonas aeruginosa (Pa) flagellin could afford protection in two lethal mouse models of Pa infection. To that end, rabbit polyclonal antibodies were generated against the N'-terminal domains (amino acids 1-156) of recombinant Pa01 or Salmonella muenchen flagellins, termed anti-N'-fla-b and anti-N'-fla-Sm, respectively. In vitro, anti-N'-fla-b but not anti-N'-fla-Sm IgG specifically recognized recombinant and Pa endogenous flagellin type b proteins, total bacterial lysates of Pa type b, and inhibited Pa01 invasion into A549 cells. In vivo, administration of anti-N'-fla-b afforded a remarkable improvement in survival in lethal peritonitis (90% vs. 12% in control; p<0.001) and burn infection (83% vs. 8-17% in control groups; p<0.005) Pa models. These findings would suggest that the N'-terminal domain of Pa flagellin harbors critically important bioactive domains and that an antibody-targeted, neutralization approach directed at this region could provide a novel therapeutic strategy to combat Pa infection.