Characterization of antibody-mediated inhibition of Pseudomonas aeruginosa adhesion to epithelial cells

Abstract

An enzyme-linked immunosorbent assay system was developed and used to study adhesion of Pseudomonas aeruginosa to human epithelial cells and the abilities of specific antibodies to inhibit this process. Human buccal epithelial cells coated onto microtiter plates were incubated with P. aeruginosa suspensions, and adherent bacteria were detected by using anti-P. aeruginosa serum and a horseradish peroxidase-conjugated secondary antiserum. Adhesion, quantitated as an increase in A405, varied linearly with increasing numbers of bacterial CFU added per well in the range of 10(5) to 10(8) CFU per well. Adhesion of P. aeruginosa increased following trypsinization of buccal epithelial cells. Preincubation of bacteria with monoclonal antibodies directed against P. aeruginosa outer membrane protein H2 inhibited adhesion with all eight of the isolates tested. Preincubation of P. aeruginosa with sera from infected cystic fibrosis patients also resulted in inhibition of adhesion in the enzyme-linked immunosorbent assay system. This inhibitory activity was shown to be due to two factors: P. aeruginosa-specific immunoglobulin G and a non-immunoglobulin G serum component. These data support the hypothesis that bacterial components other than pili are involved in adhesion and suggest that anti-P. aeruginosa antibodies may be of use in preventing adhesion and subsequent colonization with P. aeruginosa.