Pooled human immunoglobulins reduce adhesion of Pseudomonas aeruginosa in a parallel plate flow chamber

The influence of pooled polyclonal immunoglob- ulin (IgG) interactions with both bacteria and model sub- strates in altering Pseudomonas aeruginosa surface adhesion is reported. Opsonization of this pathogen by polyclonal hu- man IgG and preadsorption of IgG to glass surfaces both effectively reduce initial deposition rates and surface growth of P. aeruginosa IFO3455 from dilute nutrient broth in a par- allel plate flow chamber. Polyclonal IgG depleted of P. ae- ruginosa-specific antibodies reduces the initial deposition rate or surface growth to levels intermediate between ex- posed and nonexposed IgG conditions. Bacterial surface properties are changed in the presence of opsonizing IgG. Plateau contact angle analysis via sessile drop technique shows a drop in P. aeruginosa surface hydrophobicity after IgG exposure consistent with a more hydrophilic IgG sur- face coat. Zeta potential values for opsonized versus nonop- sonized bacteria exhibit little change. X-ray photoelectron spectroscopy measurements provide surface compositional evidence for IgG attachment to bacterial surfaces. Surface elemental ratios attributed to IgG protein signals versus those attributed primarily to bacterial polysaccharide sur- face or lipid membrane change with IgG opsonization. Di- rect evidence for antibody-modified P. aeruginosa surface properties correlates both with reduction of bacterial adhe- sion to glass surfaces under flow in nutrient medium re- ported and previous reports of IgG efficacy against P. aeru- ginosa motility in vitro and infection in vivo. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 51, 224-232, 2000.