title: Demonstration of human immunoglobulin G Fc-binding activity in oral bacteria.
abstract: Nonimmune binding of immunoglobulins via the Fc fragment may reduce opsonization and phagocytosis of bacteria and is thus considered a virulence factor. The aim of this study was to investigate a wide range of oral bacterial strains for the presence of human immunoglobulin G (IgG) Fc-binding activity. A total of 132 strains representing 40 different gram-positive and gram negative bacterial species were tested for IgG Fc-binding activity by using a fast and simple dot blot procedure with horseradish peroxidase-conjugated Fc fragments from human IgG. Neither the human nor animal biotype of Porphyromonas gingivalis possessed IgG Fc-binding activity. The strongest positive reaction of gram-negative species with the IgG Fc fragments were obtained with strains of Prevotella intermedia and Fusobacterium nucleatum. Among the gram-positive bacteria tested, Peptostreptococcus micros, Lactobacillus spp., and several species of streptococci possessed IgG Fc-binding activity. In the present investigation, the ability of several oral bacterial species to bind IgG Fc fragments was demonstrated. This factor represents a potential virulence determinant as it may help pathogenic oral bacteria escape host defense mechanisms.
mesh_terms: D001666:Binding Sites, Antibody; D006090:Gram-Negative Bacteria / Q000276:immunology* / Q000472:pathogenicity; D006094:Gram-Positive Bacteria / Q000276:immunology* / Q000472:pathogenicity; D006801:Humans; D009055:Mouth / Q000276:immunology / Q000382:microbiology*; D010510:Periodontal Diseases / Q000276:immunology / Q000382:microbiology; D017452:Receptors, IgG / Q000032:analysis*; D014774:Virulence / Q000276:immunology
chemical_list: D017452:Receptors, IgG