Antibodies that bind to fimbriae block adhesion of Streptococcus sanguis to saliva-coated hydroxyapatite

Abstract

Antibodies raised against a fimbriated, adhesive strain of Streptococcus sanguis (FW213) were found to block the adhesion of this organism to saliva-coated hydroxyapatite. Antibodies were made specific for adhesion antigens by adsorption with isogenic, nonadhesive mutants (for rabbit polyclonal adsorbed antibody) or selection based on nonreactivity with two nonadhesive mutants (for monoclonal antibody). Rabbit antibody raised against isogenic, nonfimbriated nonadhesive mutants served as a control for antibodies present, but not related to fimbriation. Adsorbed antibody and monoclonal antibody were shown to be specific for fimbriae (antigen 1), since both antibodies could be seen by immune electron microscopy to bind 3.6-nm fimbriae, reacted only with the fimbriated parent and not the mutants in a whole bacterial cell enzyme-linked immunosorbent assay, and could immunoprecipitate fimbriae from fimbrial extracts of FW213. Antibodies isolated from preimmune and mutant sera did not react with fimbriae in any of the above assays. Only adsorbed antibody and monoclonal antibody were capable of blocking the adhesion of FW213 to saliva-coated hydroxyapatite. Adsorbed antibody, purified to immunoglobulin G (IgG), was an effective inhibitor of adhesion without causing interfering cellular aggregation. Monoclonal IgG, papain-cleaved to Fab fragments to prohibit cell-to-cell cross-linking, was also a potent inhibitor of S. sanguis FW213 adhesion. Both IgG from mutant sera and Fab fragments from normal mouse IgG could not be shown to block adhesion. These data further support the hypothesis that S. sanguis fimbriae are involved in adhesion.

Effect of material characteristics and/or surface topography on biofilm development

“…Streptococcal and actinomyces strain, the early colonizers, bind specific salivary molecules (Fachon-Kalweit et al 1985;Fives-Taylor & Thompson 1985;Mergenhagen et al 1987). Streptococci (especially Streptococcus sanguis), the principal early colonizers, bind to acidic proline-rich proteins and to other receptors in the pellicle like a-amylase and sialic acid (Hsu et al 1994;Scannapieco et al 1995).…”

Identification of dipeptide repeats and a cell wall sorting signal in the fimbriae‐associated adhesin, Fap1, of Streptococcus parasanguis

“…Surface fimbriae were removed from S. parasanguis FW213 or VT321 by pulse blending in 3 M potassium iodide as described previously (Fachon-Kalweit et al, 1985). The resulting preparation was used as partially purified fimbriae.…”

“…Adhesion of S. parasanguis to saliva-coated hydroxyapatite (SHA) beads was performed as described previously (Fachon-Kalweit et al, 1985;Wu et al, 1998). [ 3 H]-thymidine-labelled bacteria bound to SHA were determined by liquid scintillation counting.…”

“…Non-fimbriated isogenic mutants of FW213 do not adhere to SHA (Fives-Taylor and Thompson, 1985). A fimbriae-specific antiserum of FW213 inhibits the adherence, suggesting that the corresponding antigens are involved in adhesion (Fachon-Kalweit et al, 1985). Two adhesins have been isolated from FW213.…”

Cell surface mutants of Streptococcus sanguis with altered adherence properties

“…Individual molecules or "adhesins" involved in the various adhesion processes have not been identified. Evidence suggests that surface proteins (16,24,33,35), and proteinaceous structures such as fimbriae (6,8,9,12) and fibrils (14,29) may contribute to surface hydrophobicity and to adherence. However, surface labelling of S. sanguis cells reveals that at least 30 proteins are exposed at the cell surface (1,16).…”