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

The influence of pooled polyclonal immunoglobulin (IgG) interactions with b oth bacteria and model substrates in altering Pseudomonas aeruginosa surfac e adhesion is reported. Opsonization of this pathogen by polyclonal human I gG and preadsorption of IgG to glass surfaces both effectively reduce initi al deposition rates and surface growth of P. aeruginosa IFO3455 from dilute nutrient broth in a parallel plate flow chamber. Polyclonal IgG depleted o f P. aeruginosa-specific antibodies reduces the initial deposition rate or surface growth to levels intermediate between exposed and nonexposed IgG co nditions. Bacterial surface properties are changed in the presence of opson izing IgG. Plateau contact angle analysis via sessile drop technique shows a drop in P. aeruginosa surface hydrophobicity after IgG exposure consisten t with a more hydrophilic IgG surface coat. Zeta potential values for opson ized versus nonopsonized bacteria exhibit little change. X-ray photoelectro n spectroscopy measurements provide surface compositional evidence for IgG attachment to bacterial surfaces. Surface elemental ratios attributed to Ig G protein signals versus those attributed primarily to bacterial polysaccha ride surface or Lipid membrane change with IgG opsonization. Direct evidenc e for antibody-modified P. aeruginosa surface properties correlates both wi th reduction of bacterial adhesion to glass surfaces under flow in nutrient medium reported and previous reports of IgG efficacy against P. aeuginosa motility in vitro and infection in vivo. (C) 2000 John Wiley & Sons, Inc. I Biomed Mater Res, 52, 224-232 2000.